Micro Decision Service Guide
Contents
1. REVERSE RESET SWITCH PI IF IT STILL DOES NOT Lir REPLACE SWITCH 2 VERIFY SWITCH SETTINGS TERMINAL ANO COMPUTEF DOES TERMINAL PASS SELF TEST POWER ON COMPUTER CHECK ARE REPLACE POWER VOLTAGES wee SUPPLY CORRECT PO VOLTAGES SUPPLY IS SIGN ON MESSAGE DISPLAYED RECONFIGURE CABLE TERMINAL AND OR S hg R YES REPLACE MOTHERBOARD A vel 7 0 Part I Section 6 Troubleshooting Procedures 09 23 83 Table 6 1 Continued Troubleshooting Flowchart REPLACE PASS ROM AND RAM NO MOTHERBOARD INSERT SYSTEM DISKETTE PRESS RETURN DOES CHECK DRIVE ARE REPLACE SYSTEM VOLTAGES AND VOLTAGES POWER SUPPLY 800T DATA CABLES AND CABLES AND OR 6000 DATA CABLES INSERT DIAGNOSTIC REPLACE DISK AND RUN MEMORY DISK TEST DRIVE PASS MEMORY TEST REPLACE MOTHERBOARD VERIFY ALL DRIVE CONNECTIONS AND DATA CABLE BEFORE REPLACING DRIVE RUN DISK TEST REPLACE NO FAILING DRIVE YES DH H tun Part I Section 6 Troubleshooting Procedures 09 23 83 Table 6 1 Continued Troubleshooting Flowchart RUN PAINTER PORT TEST PASS PRINTER PORT TEST REPLACE CABLE RESET SWITCH SETTINGS YES YES REPLACE MOTHERBOARD RETURN WORK ING UNIT TO CUSTOMER wt rd Part I Section 6 Troubleshooting Procedures 02. 26 27 28 29 30 31 32 DB 9 10 11 12 13 14 15 16 DB 33 34 35 36 37 38 39 49 DB 17 18 19 20 21 22 23 24 Track Data In order for the Micro Decision to correctly access the diskette the following data MUST be on sectors 1 and 2 of track f Data for track sector 1 of single sided diskettes 900D 099A 0918 2993 FEQ FE 1 FEQ2 FE 3 FE 5 FE 8 FE B FE E FE F FEL FE11 FELZ FELS FE16 FE17 FE1C FELF FE22 FE26 FE2A FE2E FE32 FE36 FE3A FE3D FE89 FE82 FE84 FE86 FE88 FE89 FE8B FE8C FE8D FE8E FEJ FE92 FE93 3E CH 32 FDFF CD FDFF 21 FFFE 21 0917 31 FF0 CD 9993 C3 909018 D 9A 4E 6F 74 29 61 28 53 59 53 54 45 4D 29 44 69 73 6B 65 74 74 65 2E D 9A 99 2999 9900 9099 9909 9928 94 r SE 97F CH g CR LF BTERR MESG r EQU DH EQU AH EQU 18H EQU 3 ORG FE H LD A 0C9H LD FDFFH A CALL FDFFH LD HL 2 ADD HL SP LD E HL INC HL LD D HL LD HL EMSG RADD ADD HL DE EX DE HL LD SP FF H OUT fF6H A CALL MESG JP BTERR JMP TO ROM DB CR LF Not a SYSTEM Diskette DB CH LE 9 DS QFEB0H 0 FE94 FE96 FE98 FE99 Data 29D POZA 18 GIE FE FE 2 FE 3 FE S FE B FE B FE E FE F FEL FEI FE12 FE15 FE16 FE17 FE1C FEIF FE22 FE26 FE2A FE2E FE32 FE36 FE3A FE3D FE8 FE81 FE82 FE84 FE86 FE88 FE89 FE8B FE8C FE8D FESE FE90 9929 90992 El D
3. 6 External disk drives C and D are now daisy chained from drive B since the parallel connector is located where the drive expansion connector was on the Rev 1 1 board External drives are also configured differently for the Rev 2 0 board The Micro Decision uses two different Rev 2 0 board layouts One board is manufactured by Kohjinsha Inc It can be identified by the Kohjinsha label located to the right of the board near the power plugs PJ1 PJ3 on the component side The jumper for the diagnostics is labeled JP4 and is at location A 5 6 The 40 pin I O connector is at location F 1 thru K 1 Refer to Figure 5 2 for a diagram of this board The second board can be identified by the ASSEMBLED IN KOREA label located to the right of the board near the power supply Also the power connectors PJ1 are located differently location A B 8 The jumper for the diagnostics is labeled E5 and is at location A 6 7 The 40 pin I O connector is at location A 6 7 thru D 6 7 Figure 5 3 illustrates the layout of this board The two boards are functionally identical Port addresses which apply to both layouts are listed in Table 5 3 Table 5 3 Micro Decision Revision 2 0 Port Addresses PORT FUNCTION 8253 BAUD RATE GENERATOR CENTRONICS DATA PORT CENTRONICS STATUS PORT read bit 3 ACK 1 write bit 7 strobe 0 read bit 4 busy 1 All other ports remain the same as Rev l l see Table 5 1 Part I Section 5 Motherboard Revision
4. Assembled Rev 2 0 Board STROBE neg DBO DB1 DB2 DB3 DB4 DB5 DB6 DB7 Acknowledge neg Ready Busy Odd pins 1 23 33 twisted pair ground all other pins n c D The SETUP program on the CP M diskette must be used to set the CP M LST device to acknowledge the parallel port instead of the second serial port Special Notes If the terminal used with the Micro Decision will not operate at 9600 baud you must run SETUP using the CP M distribution disk ette to create a system diskette first When you do this don t be surprised when garbage appears on the screen each time you press the reset button This is a garbled version of the message that normally tells you to insert the CP M diskette and press Return It is sent out at 9600 baud so the installed terminal misinterprets it After you press Return however the new baud rate takes over and everything proceeds normally from there 5 3 2 Serial Ports The serial connectors on the Micro Decision motherboard conform to RS 232 standards and use DB 25 8 connectors Figure 5 4 shows the layout of the connector and Table 5 9 identifies the signal associated with each of the pins Top 13 12 11 10 9 8 7 6 5 4 3 2 1 Left 25 24 23 22 21 20 19 18 17 16 15 14 Figure 5 4 Serial Port Pin Arrangement Rear View 5 8 AS Za wet C Part I Section 5 Motherboard Revisions 09 23 83 Table 5 9 RS 232 Signal Desc
5. B and the other is connected to the motherboard see Section 5 3 6 Disk Drive Connector The header plug must be installed in the rear of the chassis where the knockout plug is located directly above the parallel port The cable supplied with the external drive is an identical mating cable Part I Section 5 Motherboard Revisions 09 23 83 Figure 5 11 Drive Expansion Once the new cable is installed the termination block should be removed from drive B Drive D should be terminated if it is to be the last drive on the chain Drive C is to be selected as the second drive DS2 and drive D as the third drive DS3 Drive C is not terminated unless it is the last drive on the chain then the terminator block is not removed Drive A is to be left unchanged The CP M distribution diskette must be booted to make a new CP M working diskette with the change in the number of drives installed on the system 5 3 6 Disk Drive Connector The disk drives are connected to the motherboard through two 34 pin edge connectors labeled JDO for drive A and JDl for drives B through D Drives C and D are daisy chained from drive B see Drive Expansion Section 5 3 5 The pinouts for the connectors are listed in Table 5 14 Part I Section 5 Motherboard Revisions 09 23 83 Table 5 14 Disk Drive Connectors Pin Connections INDEX INDEX DS0 DSO MOTOR DSL DIRECTION DS2 STEP MOTOR WRITE DATA DIRECTION WRITE G
6. Gm SS MICRO DECISION SERVICE GUIDE Rev 20 Koghyinsha iu a mes Copyright 1983 by Morrow Designs Incorporated 600 McCormick Street San Leandro California 94577 All rights reserved y V THE SERVICE PROCEDURES DESCRIBED IN THIS DOCUMENT ARE TO BE PERFORMED ONLY BY AUTHORIZED MORROW DESIGNS DEALERSHIPS ONLY QUALIFIED SERVICE PERSONNEL SHALL PERFORM THE REPAIRS QUALIFICATION MAY BE OBTAINED BY SATISFACTORY COMPLETION OF A MORROW DESIGNS SERVICE SEMINAR OR EQUIVALENT TRAINING AND EXPERIENCE IN PERSONAL COMPUTER SERVICE No part of this publication may be reproduced transmitted stored in a retrieval system or translated into any language or computer language in any form or by any means eletronic mechanical magnetic optical chemical manual or otherwise without the prior written permission of Morrow Designs Inc No representations or warranties express or implied are made with respect to the contents hereof including but not limited to the implied warranty of merchantability or fitness for a particular purpose Further Morrow Designs reserves the right to revise this publication and to make changes from time to time in the contents hereof without obligation to notify any person of such revision Diagnostics II is a product of SuperSoft Incorporated The documentation contained herein for this product is reproduced with the permission of SuperSoft PART I TECHNICIAN S REFERENCE COMPONENT ID AND DISASSE
7. RD RTS 14 3B 3 3A DSR RTS 13 4B 4 4A DSR CTS 12 5B 5 5A DTR CTS 11 6B 6 6A DTR CD 10 7B 3 o o i 7 7A 12V CTS 9 8B i o o 8 8A 12V Figure 5 7 Jumper Settings Pin 2 to Pin 2 Pin 3 to Pin 3 Factory Settings for JPB The printer modem port would be configured for a modem if you want to use the Micro Decision as a host computer contacting remote computers or data bases 22 2eecavas Ye nuvutLO0Oara Kevis1ons 09 23 83 The signal present on each jumper pin in JPB is shown in Table 5 11 along with the factory setting for the feeding of the signals to the RS 232 connector The reason the pin numbers appear as 1 1A is that the board may be silkscreened in either of these two ways Table 5 11 JPB Pinouts Terminal Setup RxD to UART RD to terminal DSR to terminal DSR to UART DTR from terminal DTR from UART TTL false lt 3V TTL false TTL false Receiver Clock to modem RS 232 Receiver input TTL output of RS 232 rcvr N C Baud Clock output Baud Clock input to UART TC External Clock RS 232 level clock out DET alternate handshake CTS to UART CD from terminal CTS to terminal CTS to UART RTS from terminal RTS from UART TxD from UART TD from terminal This signal configuration is accomplished through circuit board wiring and the factory jumper settings as shown in Figure 5 8 Part I Section 5 Motherboard Revisions 09 23 83 TD 26 1B 0 1
8. RESET 5 Jan 7 71000 9 1010 11 1020 13 1030 15 AB3 17 AB2 19 ABl 21 ABO 23 DE 25 DB6 27 DBS 29 DB4 31 DB3 33 DB 2 35 DB1 37 DBO 39 45v 38 45v 40 12v 36 12v 34 unlabeled pins are grounded The 40 pin 1 0 connector is at location F 1 through K 1 or locations A 6 7 through D 6 7 depending on the board lay out Either board may be supplied with a 2X20 header block or solder holes only BAUD RATE GENERATOR The baud rates for the Micro Decision are software selectable through the SETUP prograr The baud rate generator is an Inte 8253 counter timer chip which is accessed through ports OP0 0F3h Channel 0 is used for Floppy Drive Timing and should not be written to Channel 1 is serial port 1 baud Channel 2 is serial port 2 baud The seven most popular baud rates 110 300 600 1200 2400 4800 and 9600 can be chosen through the SETUP program for both serial ports The SETUP program also enables you to choose between software handshaking XON XOFF or hardware handshaking DTR pin 20 on the second serial port fe DISK DRIVE CONNECTOR The disk drives are connected to the motherboard through two 34 pin edge connectors labeled JDO for drive A and JD1 for drives B through Dp Drives C and D are daisy chained from drive B The pin outs for the connectors are listed below JDO 8 10 16 18 20 22 24 26 28 30 32 INDEX DSO MOTOR DIRECTION STEP WRITE DATA
9. block at that location and turn on the computer If the power on memory test passes the following should appear on the screen l PORT 1 N 2 PORT 2 gt BARBER POLE TEST PATTERN 3 CENTRONICS PORT 4 LOOP BACK ON PORT 2 5 RAM TEST 6 FDC R W 7 FDC SEEKTEST B VFO TEST 9 BOOT Enter Description of Test NOTE To end a test press any key and wait for the Diagnostics Menu to reappear n l Port 1 test This test transmits a barber pole character pattern to the CRT 2 Port 2 test This test transmits a barber pole character pattern to the device connected to serial port 2 3 Centronics port test This test transmits a barber pole character pattern to a printer via the Centronics parallel port 4 Loop back on port 2 test This test verifies proper operation of the 8251 USART on port 2 A wrap plug with pins 2 and 3 jumpered and pins 5 and 20 jumpered must be used This test will immediately show pass or fail 5 Ram Test This test runs a continuous ram test The test will show any address which is found to be bad the value expected and the value read from the bad address rane a 9euLLun 2 MmOCnerooard Revisions 09 23 83 6 FDC Floppy Disk Controller Read Write test This test performs a worst case read write test on the inner most track of a diskette reporting errors to the screen A freshly formatted diskette should be used 7 FDC Seektest This test will perform a bu
10. inside of the back panel remove it by removing the four screws that secure t to the back panel Rest the unit on its side If disassembling a Revision A or Revision B chassis remove the four screws on the bottom that bold the motherboard to the chassis see Figure 2 5 or 2 6 If working with a Revision C chassis remove the two screws on the bottom and the two screws on the rear panel which secure the motherboard see Figure 2 3 and Figure 2 7 Support the board with your hand do NOT push hard against it when you remove the last Screw to keep it from falling Put the unit back on its bottom Slide the motherboard toward the front of the chassis until the peripheral cable connectors are on the inside of their cutouts Then gently lift the board out by its rear end sliding it away from the front of the chassis as you go 5 3 Revision 2 0 Features The Micro Decision Rev 2 0 board differs with the Rev 1 0 board in several aspects l 2 3 4 5 The addition of a Centronics compatible parallel port Software selectable baud rate generator Intel 8253 40 pin I O connector for future enhancements Internal ROM diagnostics for testing the function of the board Improved floppy disk data separator Part I Section 5 Motherboard Revisions 09 23 83 The new Rev 2 0 board will not effectively run CP M with a Morrow revision lower than 2 1 The Rev 1 0 board will not run CP M with a Morrow revision greater than Rev 1
11. you must first remove the power supply see Section 4 and then unscrew the support bracket Part I Section 3 Disk Drive Configuration and Removal 09 23 83 de Toggle the L bracket connected to the drive as shown in Figure 3 4C Figure 3 4C MD II Revision B and C Chassis Drive Removal 4 Carefully pull the drive toward the rear of the unit E et C Part I Section 4 Power Supply Removal 09 23 83 4 POWER SUPPLY REMOVAL The location of screws used to remove the power supply is iden tical for all chassis revisions Figure 4 1 shows the Revision B chassis but can also be used as reference for Revision A and Revision C power supply removal Procedures for power supply removal which are dependent on the type of chassis being serviced are documented below 4 1 Revision A Chassis 1 If removing the power supply from an MD II remove the B drive as described in Section 3 1 2 Disconnect the power supply harness from the mother board and the cable that powers the LED in the Reset switch 35 With the unit upside down remove the four screws on either side of the power supply s ventilation grill see Figure 4 1 The power supply will drop lightly onto the bench 4 When installing the new power supply route its wires as far away from drive B as possible Make sure you do not pinch any wires between the power supply and the chassis 4 2 Revision B and C Chassis li With the unit upsid
12. 1A RD e ME EE E a RTS 24 3B Ge 0 3 3A DSR RTS 23 4B o 4 AA DSR CTS 22 5B o PER 5 5A DTR CTS 21 6B o e 6 6A DTR CD 20 7B 9 e 7 7A lt 3V CTS 19 8B La 29 4 8 8A 3v DET 18 9B o o 9 9A lt 3V 17 10B o o 10 10A 16 11B o o 11 11A p N RxCB 15 12B o 12A U2CLK 14 13B o 13 13A Figure 5 8 Factory Jumper Settings for JPB JPB Settings for Modems As was mentioned above for JPA the jumper setting for JPB depend on the type of modem cable you have For cables that crisscross pins 2 and 3 arrange the jumpers as shown in Figure 5 9 5 13 salt i oeccion gt Motherboard Revisions 09 23 83 TD 25 28 o o 2 21 RD RTS 24 3B o 3 3A DSR RTS 23 4B L o 4 4A DSR CTS 22 5B 5 5A DTR CTS 21 6B sz 6 6A DTR CD 20 7B 9 o 7 7A lt 3V CTS 19 88 o 0 8 ga lt 3V DET 18 9B o o 9 9A 3V 17 10B o o 10 10A 16 11B o o 11 11A RxCB 15 12B o 12 12A U2CLK 14 13B o 13 13A Figure 5 9 JPB Jumper Settings Crisscross Modem Cable When using a modem cable that connects pin 2 to pin 2 and 3 to 3 use of the jumper setup is the same as above except for positions l 1A 2 2A 25 2B and 26 1B See the difference below TD 26 1B l 1A RD TD 25 2B 2 2A RD Figure 5 10 Alternate JPB Jumper Settings Sample RS 232 cable configurations are provided in Table 5 12 following Part I Section 5 Mot
13. 20 44 FE32 69 73 6B 65 FE36 74 74 65 2E FE3A D 9A 99 DB CR LF FE3D DS OFE88H 9
14. 3 83 83 83 83 83 SUBJECT Micro Decision 1 3 PROM Software Micro Decision Power Supply Upgrade Micro Decision Software Remake OBSOLETE OBSOLETE MDT20 Terminal Terminal PROMS MDT50 Terminal Terminal Service Micro Decision Printer Port Info MDT20 Terminal Terminal Service MDT20 Terminal Terminal Mod Micro Decision Terminal Configuration Cancelled MP100 MP200 MP300 Printer Service Micro Decision Rev 2 0 Board Release DJDMA Board S 100 Bus Standards Cancelled Quest Software Software Support 09 23 83 ISSUED BY T T Fruehan Fruehan Fruehan Fruehan Patel Fruehan Patel Fruehan Fruehan Dean Fruehan Tilbury Fruehan cane A ki os veuScOmer service Bulletin Index 17 18 19 20 21 22 23 24 Jun 83 Jul 83 Aug 83 Aug 83 Sep 83 Sep 83 Micro Decision Software Upgrade Cancelled Micro Decision PROM Software Upgrade Cancelled MDT 20 Terminal Terminal Service Micro Decision Printer Patch Decision One Software Upgrade Decision One Micronix 09 23 83 T Fruehe Rowe Dean Hamel Bingt Bingk IVIUKKUW 600 McCormick Street O San Leandro O California D 94577 Morrow Micro Decision Board Revision 2 0 Technical Information Supplement MICRO DECISION Technical Support Services D USK PARALLEL PORT The Micro Decision s parallel port is a Centronics co
15. 9 23 83 6 3 Measuring Power Supply Voltages If you reach the point in the troubleshooting flowchart that tells you to check power supply voltages here is what you do 1 With the power cord unplugged remove the cover as described in Section 2 Then reconnect the power cord and turn the power switch ON 2 Connect the ground lead probably black from the volt meter to an exposed metal part of the chassis prefer ably a drive Use an alligator clip for best results 3 Locate connector PJ3 on the motherboard next to the power supply Make sure your meter is set up to measure volts on the other meter probe into pin 1 the red cable lead You should measure 5 volts 4 At pin 4 the blue lead the 12 volts that powers the disk drive motors should be present 5 To check the and 12 volts to Rev 2 0 motherboard cir cuitry use the 40 pin I O connector on the board 5v Pins 38 and 40 12v Pin 36 12v Pin 34 Voltage 5v and 12v to the Rev 1 1 boards can be checked from the disk drives 12 volts can be checked from the 1488 serial buffer at location A 1 6 If any or all of the voltages are missing or if they vary from the specified voltage by more than 10 the power supply should be replaced Refer to Section 4 Power Supply Removal for instructions However this may not fix the problem see Tips below 7 Recheck the voltages even if the problem is cleared up this is to be sure that nothing is puttin
16. ATE STEP TRACK 0 WRITE DATA WRITE PROTECT WRITE GATE READ DATA TRACK 0 SIDE SELECT WRITE PROTECT READ DATA SIDE SELECT E All odd numbered pins on JDO and JDl are grounded 5 20 Part I Section 6 Troubleshooting Procedures 09 23 83 6 TROUBLESHOOTING PROCEDURES 6 1 Tools Required You will need the Phillips screwdriver the Diagnostic II diskette and a digital voltmeter The meter Kiethley model 132 or equivalent is needed when the power supply is suspect and is also useful for checking the continuity of cables Another helpful device is a floppy diskette head cleaning kit 6 2 Troubleshooting Flowchart Use the troubleshooting flowchart see Table 6 1 for isolating a defective assembly within the Micro Decision as well as for determining whether the trouble lies outside the computer in cables or peripherals for example Follow the procedure as described in the figure If you find that the problem lies somewhere in the Micro Decision you will be instructed to run the diskette diagnostic programs You will need the Diagnostics II diskette and a terminal known to be working properly amar a ecveeivu us roubiesnooting Procedures 09 23 83 POWER ON MORROW TERMINAL TURN OFF TERMINAL PLUG IN CORD IS BRIGHTNESS TURNED TURN UP BRIGHTNESS CURSOR VISIBLE REPLACE TERMINAL PUT TERMINAL IN LOCAL RUN TYPE ESC Y TERMINAL SELF TEST
17. M256 l LED Panel l LED Panel l Multi I O l Reset Harness l Reset Harness l DJDMA l Connector 4P l Connector 4P 1 HDDMA 1 Connector LED 1 Connector Fl 2 Cable 34 S 4 Rubber Ft l Front Panel 6 Stand offs l Connector LED l Connector F1 2 Cable 34 S 4 Rubber Ft l Front Panel 6 Stand offs 2 Sw Pwr Supply l DEC Buss 14 s l Reset switch l Complete set of manuals for each bd Notes Service Guide for Micro Decision 225 00 Set of Manuals for Micro Decision 54 00 Set of Manuals for Decision 1 60 00 Above prices are NOT discountable All parts carry Morrow s factory warranty of 30 days from date of purchase Remedy is limited to repair or replacement of the defective part at the option of Morrow Parts supplied are reconditioned and are not to be resold as new In any case Morrow will not be liable for consequential damages arising from the use of its products Prices supersede those published June 1 1983 in Dealer Information Bulletin 5 Prices are subject to chang without notice To order kits please contact Customer Service A maximum of one 1 service kit may be purchased for each 10 systems H WO C Part I Section 8 Customer Service Bulletin index 8 CUSTOMER SERVICE BULLETIN INDEX BULL 1 10 11 12 12 A 13 14 15 16 DATE Nov Nov Dec Feb Mar Mar Mar Apr Apr May May May Jun 82 82 82 83 83 83 83 8
18. MBLY PREFACE The Micro Decision Service Guide is organized in two distinct parts Part I serves as a technician s reference guide the modular assembly of the Micro Decision is discussed in detail and the disassembly procedures for each module is provided Troubleshooting and parts replacement is also covered in Part I Part 11 Diagnostics II User s Manual follows the Customer Service Bulletin Index This part of the Micro Decision Service Guide details the testing of each major Micro Decision component The Morrow Designs Micro Decision computer system is designed for serviceability A reduced part count and modular assembly approach contribute to reliability and ease of service The Central Processing Unit memory circuits communications port and all support electronics reside on a single printed circuit board motherboard One power supply assembly provides all DC operating voltages to the motherboard and the internal disk drives The motherboard power supply and disk drives are typically replaced as complete units Thus repairs can usually be performed with a minimum of troubleshooting for you and downtime for the owner No special tools are required beyond normal hand tools A digital voltmeter is needed for power supply troubleshooting and cable continuity tests User selectable options are limited to baud rates hardware software printer handshaking and terminal modem selection for the RS 232 connectors These are desc
19. N REV 1 1 PJ3 UART CI EH SW1 IJ DE P32 CO ECH SW2 fs CS 43 Ea Es s 8251 CO CC UART ca CC CC EZ RAM LOCATION CZ EH 9 i Figure 5 1 Micro Decision Rev 1 1 Motherboard rart l section 5 Motherboard Revisions 09 23 83 Table 5 1 Micro Decision Rev 1 1 Port Addresses FUNCTION MOTOR CHECK PORT ROM ENABLE DISABLE out enable in disable VFO COUNT SET PORT MOTOR amp SHIFT CONTROL UPD 765 STATUS UPD 765 DATA lst SERIAL PORT DATA lst SERIAL PORT STATUS 2nd SERIAL PORT DATA 2nd SERIAL PORT STATUS Table 5 2 Rev 1 1 Bit Map RAM Location LOCATION 0 1 2 3 4 5 6 7 W D ti Sot Part I Section 5 Motherboard Revisions 09 23 83 5 2 Motherboard Removal CAUTION ls 2 When handling motherboards you should take care to avoid damage to them through electrostatic discharge Ideally you should wear a grounded wriststrap but we doubt you will so at least moisten carpets with a spray bottle and discharge yourself by touching the Micro Decision chassis frequently as you work Handle the board by the edges and avoid touching IC leads or solder connections Remove both disk drives as described above Disconnect all cables from the motherboard You will not be able to disconnect the ribbon cables leading to the disk drives as they are glued to the motherboard and are replaced along with the board If the unit has a cord pan rectangular box attached to the
20. ST OF TABLES Micro Decision Rev 1 1 Port Addresses eee e Rev 1 1 Bit Map RAM Location o ooooooonoooonsoponsn Micro Decision Revision 2 0 Port Addresses ee Rev 2 0 Kohjinsha Bit Map RAM Location oce Rev 2 0 Korean Assembled Bit Map RAM Location Parallel Port Addresses Abu au es Parallel Port Signals Kohjinsha Rev 2 0 Board Parallel Port Signals Korean Assembled Rev 2 0 Board RS 232 Signal Descriptlons esee o o eoo eo JPA Pinouts Terminal Setup cec eee eoe ees D l JPB Pinouts Terminal Setup ua D Sample RS 232 Cable ConfiguratioNS ooooooooooooooo 5 15 40 Pin I O Connector Pin Connections 5 16 Disk Drive Connectors Pin ConnectionsS 5 20 rid e e rer T 1 O W ons CNL i to wm pH N Troubleshooting Elowchart ee enee eee ooo s 6 2 Replacement Parts LiSt o ooomoosnrrononprrrrsrnonaross J Dealer Service EE 7 2 tp get mor Part I Section 1 Tools Required for Disassembly 1 TOOLS REQUIRED FOR DISASSEMBLY You will need a Phillips screwdriver magnetic Keep any magnetized tools contain valuable files To help insure against callbacks you wriststrap that is connected to the whenever you handle the mother board preferably size away from disket should wear a Micro Decision 09 23 83 2 and tes that grounding chassis Part I Section 2 Cover Removal 09 23 83 2 CO
21. T RTS from terminal RTS from UART TxD from UART TD from terminal z Q to ei OY i GO Ut OO YA amp E t 00 This signal configuration is accomplished through circuit board wiring and the factory jumper settings as shown in Figure 5 5 When setting up JPA for use with a modem on the terminal port the jumper modifications depend on whether the modem cable has pin 2 at one end tied to pin 3 at the other and vice versa This crisscrossing is frequently but not always found in modem cables If you re not sure which type you have use an ohmmeter or continuity tester to find out B sec P uer um TD 15 2B Ee ME 2 2A RD RTS 14 3B Doan 3 3A DSR RTS 13 a o e 4 4a DSR CTS 12 5B i o o i 5 5A DTR de ate ba uu CD 10 7B o o i 7 7A 12V CTS 9 8B 8 8A 12V Figure 5 5 Factory Jumper Settings for JPA mo car rart i pection 5 Motherboard Revisions 09 23 83 JPA Settings for Modems For cables that crisscross pins 2 and 3 arrange the jumpers as shown below x sum lo o 1 1A RD a Benl o S e RTS 14 3B 3 3A DSR RTS 13 4B 4 4A DSR CTS 12 5B 5 5A DIR CTS 11 6B 6 6A DTR CD 10 B i o o i 7 7 12v CTS 9 88 o o i 8 8A 12V earn orar ronca ross raso Figure 5 6 JPA Settings for Modems For cables that connect pin 2 to pin 2 and pin 3 to pin 3 set the jumpers as shown in Figure 5 7 following TD 16 1B 1 1A RD TD 15 2B 2 2A
22. VER REMOVAL Before removing the cover turn off the Micro Decision and unplug the equipment from the ac power source Failure to do so pre sents a serious hazard to the equipment and to service personnel Next disconnect all cables from the rear of the unit At this printing Morrow has installed three versions of Decision chassis For clarification sion A original model Revision B chassis style Micro we refer to them as Revi and Revision C newest The simplest way to distinguish the three chassis revisions is to view the unit from the rear Revision A has a cord pan installed and the AC power cord is hardwired see Figure 2 1 TT Figure 2 1 Revision A Chassis The Revision B chassis does not have a cord pan and the power cord plugs into the back of the unit Figure 2 2 Revision B Chassis Part I Section 2 Cover Removal 09 23 83 The third chassis style Revision C is similar to the Revision B chassis but can be identified by the knockout provided on the rear panel for a fan The fan is installed in MD XI units only Another distinguishing characteristic is the location of the drive expansion knockout It is located in the upper right portion of the Revision C rear panel rather than at the base The Revision C chassis also has two screws provided for removal of the Micro Decision motherboard FAN KNOCKOUT ORIVE MOTHERBOARO EXPANSION REMOVAL KNOCKOUT a Figure 2 3 Revision C Chass
23. W 32 DW 2 DB PE1H DS 193 9 for track sector 1 of double sided diskettes 99 99 pp 3E C9 32 FDFF CD FDFF 21 FFFE 39 5E 23 56 21 9917 19 EB 31 FFA D3 F6 CD 993 C3 0018 D JA 4E 6F 74 20 61 29 53 59 53 54 45 4D 20 44 69 73 6B 65 74 74 65 2E D HA PP 29 9909 999 9999 928 4 F 1 2C2 PPBF e EQU DH EQU AH EQU 18H EQU 3 ORG FE H NOP NOP NOP LD A PC9H LD fFEFFH A CALL FDFFH LD HL 2 ADD HL SP LD E HL INC HL LD D HL LD HL EMSG RADD ADD HL DE EX DE HL LD SP FFPPH OUT PF6H A CALL MESG JP BTERR 7JMP TO ROM DB CR LF Not a SYSTEM Diskette DB CR LF f DS OFE8 H S FE92 ES DB E H FE93 gg DB f FE94 29039 DW 48 FE96 9092 DW 2 FE98 89 DB 89H FE99 DS 193 9 Data for track f sector 2 of single and double sided diskettes 99D CR EQU DH 099A LF EQU 9AH 918 BTERR EQU 18H 9993 MESG EQU 3 L ORG FE H FE 9 NOP FEg1 99 NOP FE2 99 NOP FEP3 3E C9 ID A C9H FE 5 32 FDFF LD FDFFH A FEg8 CD FDFF CALL FDFFH FE B 21 FFFE RADD ID HL 2 FEJE 39 ADD HL SP FE F SE ID E HL FE19 23 INC HL FELL 56 LD D HL FE12 21 90917 LD HL EMSG RADD FE15 19 ADD HL DE FE16 EB EX DE HL FE17 31 FF00 LD SP FF H FELA D3 F6 OUT OF6H A FE1C CD 9993 CALL MESG FE1F C3 9918 JP BIERR JMP TO ROM FE22 D JA 4E 6F EMS DB CR LF Not a SYSTEM Diskette FE26 74 20 61 26 FE2A 53 59 53 54 FE2E 45 4D
24. WRITE GATE TRACK 0 WRITE PROTECT READ DATA SIDE SELECT JD1 INDEX DS0 DS1 DS2 MOTOR DIRECTION STEP WRITE DATA WRITE GATE TRACK O WRITE PROTECT READ DATA SIDE SELECT All odd numbered pins on JDO and JD1 are grounded Micro Decision Diskette Format Specifications Introduction This document provides details of the Micro Decision s native diskette format Micro Decision diskettes use a soft sectored double density IBM like format Both single and double sided versions of this format are supported This format is compatible with both Western Digital 179X and NEC 765 type controllers Format Characteristics All Micro Decision diskettes have 49 cylinders Single sided diskettes have one track per cylinder i e 49 tracks while double sided diskettes have two tracks per cylinder i e 89 tracks Each track has five 1k byte sectors This gives a total formatted capacity of either 2 k bytes single sided or 40k bytes double sided Two tracks 19k bytes are allocated for the bootable image of the CP M operating system And either 4k bytes single sided or 6k bytes double sided are allocated for the diskette directory This gives a total usable capacity of 186k bytes single sided or 384k bytes double sided with up to 136 files single density or 192 files double density NY Track Format _ All tracks are formated the same way only the cylinder number and head number for dou
25. ble sided diskettes are different from one track to another Number of es Decimal Value Hex of Bytes Decimal Value Hex 89 E 12 9 3 C2 1 FC Index Address Mark 5g 4E 12 3 1 I D Address Mark i 8 27 Cylinder 1 9 1 Side 1 1 5 Sector Repeat 1 3 Sector Size Code 5 Times 2 C R C V 22 4E 12 3 Al 1 FB Data Address Mark 1924 Default Data 2 85 258 4E Continue to end of track Missing clock between bits 4 amp 5 Missing clock between bits 3 amp 4 No physical skew is used that is the sectors are written in order on each track On the Micro Decision double sided diskettes are handled as 88 track diskettes with the even numbered tracks on side and the odd numbered tracks on side 1 The relationship between track cylinder and side is Track 2 x Cylinder side or conversly Cylinder Side Integer Track 2 Least Significant Bit Track nos CP M Parameters The parameters for the DISKDEF macro are Single Sided Double Sided FSC 1 1 LSC 49 4 SKF BLS 2048 2648 DKS 95 195 DIR 128 192 CKS 128 192 OFS 2 2 These parameters produce a DPB with the folowing values Single Sided Double Sided SPT DW 49 DW 4f BSH DB 4 DB 4 BIM DB 15 DB 15 EXM DB 1 DB 1 DSM DW 94 DW 194 DRM DW 127 DW 191 ALA DB 192 DB 224 AL1 DB Y DB CKS DW 32 DW 48 OFF DW 2 DW 2 A hand coded translation table must be provided ad shown below XLT DB 1 2 3 4 5 6 7 8 DB 25
26. bove drive A in the left half of the unit as you face the front Drive removal depends on the configuration of the drives and the type of chassis in which these drives are installed NOTE When removing MD II or MD III drives from a Revision 1 1 motherboard it is very important that you mark disk drives as A or B since they must go back in the same positions from which they came The best method is to place a piece of masking tape on the B drive with a note next to power supply 3 1 MD I and MD II Revision A Chassis l Turn the unit upside down and remove the three screws that anchor the drive you wish to remove Figure 3 1 points out the positions of the screws for both drives 2 While holding the loosened drive in place turn the unit right side up Disconnect the drive cable and carefully pull it backwards out of the chassis rart I Section 3 Disk Drive Configuration and Removal 09 23 83 W Figure 3 1 MD I MD II Drive Removal Revision A Chassis 3 2 MD III Revision A Chassis i Follow the instructions provided for MD I and MD II drive removal Section 3 1 2 Remove the strap which holds the two drives together Remember to mark one or both of the drives drive B must be reinstalled on top of drive A 3 3 MD I and MD III Revision B and C Chassis l Disconnect the flat ribbon cable s from the connector s on the drive s Then disconnect the cable s to the motherboard For MD III confi
27. e down remove the four screws on the either side of the power supply s ventilation grill see Figure 4 1 The power supply will drop lightly onto the bench 2 If removing the power supply from an MD II remove the B drive as described in Section 3 4 3 Disconnect the power supply harness from the mother board and the cable that powers the LED in the Reset switch 4 When installing the new power supply route its wires as far away from drive B as possible Make sure you do not pinch any wires between the power supply and the chassis zart a section 4 Power Supply Removal Figure 4 1 Power Supply Removal e 09 23 83 HEP oe Part I Section 5 Motherboard Revisions 09 23 83 5 MOTHERBOARD REVISIONS Morrow supports two Micro Decision Motherboard revisions Rev 1 1 ne and Rev 2 0 The Rev 1 1 boards were phased out May 27 1983 and are generally found in Revision A chassis Refer to Figure 5 1 for a layout of this board Rev 2 0 boards expand the Micro Decision capabilities There are two versions of this board one board is manufactured by Kohjinsha in Japan see Figure 5 2 and the other is assembled in Korea see Figure 5 3 These boards are generally mounted in Revision B and Revision C chassis 5 1 Revision 1 1 Details Figure 5 1 illustrates the layout of this motherboard Table 5 1 lists the port addresses and Table 5 2 provides a bit map for RAM chip replacement Ned MICRO DECISIO
28. f Screws Revision A Chassis enee aaen 2 3 Location of Screws Revision B ChasSiS oooooooooo 274 Location of Screws Revision C Chassis ceo 2 5 MD I MD II Drive Removal Revision A Chassis 3 2 MD I MD III Drive Removal Revision B and C Chassis 3 3 MD I MD III Drive Removal Revision B and C Chassis 3 3 Separating MD III Drives Revision B and C Chassis 3 4 MD II Revision B and C Chassis Drive Removal 3 5 MD II Revision B and C Chassis Drive Removal 3 5 MD II Revision B and C Chassis Drive Removal 3 6 Power Supply Removal oooooooononorormosnonno rnnoo 4 2 Micro Decision Rev 1 1 Motherboard ee eee ooo 5 1 Rev 2 0 Motherb ard Kohjinsha ee ee ee esos 5 5 Rev 2 0 Motherboard Korean Assembled oo ooooooovor 5 6 Serial Port Pin Arrangement Rear View ee D B Factory Jumper Settings for JPA eee seo eO 5710 7 JPA Settings for Modems 5 ue aso 22 et Jumper Settings Pin 2 to Pin 2 Pin 3 to Pin 3 5 11 Factory Jumper Settings for JPB eee eoo oes 5 13 JPB Jumper Settings Crisscross Modem Cable 5 14 Alternate JPB Jumper SettingGS o ooooooooooroooooonoo 9 14 Drive ExbanstOB ca opes EAE E A Y RW ee xa v Dc CG ad TN gr 3 d d dg cg Vd Wh kd un on UU Y un LD ES Y UN Y bod bh eS OOO NI ON t d GJ NJ HO be ve ce 0 0 eg wa oe ee 99 40 so eg mn uu un yog no E LI
29. g too much of a load on the power supply 6 4 Tips on Troubleshooting Power Supply Problems A voltage that is lower than it should be could be caused by leakage or shorts outside of the power supply itself Assuming that you have already substituted the power supply try disconnecting the disk drives one at a time and rechecking the voltages as you go If you get down to just the power supply and motherboard being connected and the voltage is still low then replace the motherboard Part I Section 7 Replacement Parts 7 REPLACEMENT PARTS vel W 020 SA455 020 F5200 125 MHLED 028 LED3105 080 MFP 500 PCBM Rev 1 1 or Rev 2 0 060 34122C 102 SPM 125 MHDC 500 SWPSM 125 MHRESET 096 06X14PST 096 3X6M PP 09 23 83 Table 7 1 Replacement Parts List PART NO DESCRIPTION SA455 SA200 A INSERT BRKT B LED HARNESS 1 LED 3 PC B FRONT PANEL ASSM PCB REPRO ROM A CABLE 34S 12 B STAND OFF C DC POWER CABLES POWER SUPPLY RESET HARNESS SCREW 632 TYP F SCREW 3X6MM PAN PHIL The Dealer Service Kit follows in Table 7 2 Part I Section 7 Replacement Parts 09 23 83 Table 7 2 Dealer Service Kit Effective Date October 1 1983 950 0005 00 950 0006 00 E A IT MAN 650 00 900 00 950 0007 00 Decision l 2 870 00 INCLUDES l Disk Drive 1S 2 Disk Drive 2S l HDDCA l Micro PCB l Micro PCB l MPZ80 l Micro SPS l Micro SPS 1 D
30. gurations we recommend that you mark the cables for drive B to identify them when reinstalling the drive 2 Remove the two bottom screws from the brackets on the left see Figure 3 2A Part I Section 3 Disk Drive Configuration and Removal 09 23 83 i Figure 3 2A MD I MD III Drive Removal Revision B and C Chassis bracket on the 3 Remove the screw at the base of the L right side as viewed from the front of the unit see Figure 3 2B Figure 3 2B MD I MD III Drive Removal Revision B and C Chassis 4 Slide the drive s toward the rear and out saru Aeeutiun 3 USK Drive Configuration and Removal 09 23 83 5 To separate and remove individual drives MD III remove the two bottom screws from the straps on the right side of the drives 1 mim he LU bu Figure 3 3 Separating MD III Drives Revision B and C Chassis 3 4 MD II Revision B and C Chassis l Remove the cable connectors from the drive you wish to remove 2 Remove the screw at the base of the bracket holding the two rives see Figure 3 4A V Part I Section 3 Disk Drive Configuration and Removal 09 23 83 i ne Ma l AT O O E Eon WE Ns Figure 3 4A MD II Revision B and C Chassis Drive Removal a If removing the A drive remove the two screws on the support bracket see Figure 3 4B VK Figure 3 4B MD II Revision B and C Chassis Drive Removal b If removing the B drive
31. herboard Revisions 09 23 83 Table 5 12 Sample RS 232 Cable Configurations LEGEND for Table 5 9 1 MORROW MP 200 4 SMITH CORONA EPSON IDS PRISM 2 OKIDATA C ITOH DIABLO 3 TI 810 QUME QUME NEC Xon Xoff COMREX DAISY WRITER Sample 1 Sample 2 MORROW PRINTER MORROW PRINTER Sample 3 Sample 4 MORROW PRINTER MORROW PRINTER 1 lt gt 2 a Y H cr Sample 5 MORROW PRINTER 5 15 Part I Section 5 Motherboard Revisions 09 23 83 5 3 3 40 Pin I O Connector The 40 pin I O connector connects the Micro Decision with the outside world The pin connections for the buss are listed in Table 5 13 unlabeled pins are grounded Table 5 13 40 Pin 1 0 Connector Pin Connections BRD Buffered IO Read BWR Buffered IO Write RESET Z80 Reset Line Output 4AM 4 MHz 280 Clock 1000 Decoded IO Space at Location 1010 Decoded IO Space at Location 1020 Decoded IO Space at Location 1030 Decoded IO Space at Location AB3 Address Line 3 AB2 Address Line 2 ABl Address Line 1 ABO Address Line 0 DB7 Data Bus 7 DB6 Data Bus DB5 Data Bus DB4 Data Bus DB3 Data Bus DB2 Data Bus DBL Data Bus DBO Data Bus 5v 5v 12v 12v Part I Section 5 Motherboard Revisions 09 23 83 5 3 4 ROM Diagnostics The Micro Decision Rev 2 0 board has diagnostic routines built into the 4K ROM To access the diagnostics locate the jumper labeled JP4 or ES Install a jumper
32. is 2 1 Revision A Chassis 1 Remove the four screws on the bottom that hold the cover to the chassis see Figure 2 4 2 Now remove the two screws at the upper corners of the unit s back that hold the cover to the back panel 3 Carefully remove the cover by sliding it off towards the front P ten Part I Section 2 Cover Removal 09 23 83 MOTHERBOARD SCREW LOCATIONS Figure 2 5 Location of Screws Revision A Chassis Part I Section 2 Cover Removal 09 23 83 2 2 Revision B and C Chassis i Remove the four screws closest to the edge two on either side NOTE A magnetized screwdriver is not required when working on Revision B and C chassis 2 Tip the unit and rest it on the rear panel 3 Slide the cover up and off MOTHERBOARD SCREW LOCATIONS Figure 2 6 Location of Screws Revision B Chassis Part I Section 2 Cover Removal te oe ye Figure at MOTHERBOARD SCREW LOCATIONS 2 7 Location of Screws Revision C Chassis 09 23 83 vi P Ir iC Part I Section 3 Disk Drive Configuration and Removal 09 23 83 3 DISK DRIVE CONFIGURATION AND REMOVAL There are three drive configurations for the Micro Decision MD I One 3 4 high single sided 5 1 4 inch floppy drive mounted at the left as you face the unit MD II Two 3 4 high single sided 5 1 4 inch floppy drives mounted side by side MD III Two 1 2 high double sided floppy drives stacked drive B mounted a
33. mpatible port employing a 34 pin edge connector for connection to a printer The data is transferred through a 74LS374 tri state buffer to the connector The addresses for the ports are F4 Data port FS Status port Read bit 3 1 ACK bit 4 l Busy Write bit 7 Strobe The signals for the 34 pin edge connector are Odd pins 1 23 33 twisted pair ground 2 STROBE neg 4 DBO 6 DBI B DB2 10 DB3 12 DB4 14 DB5 16 DBE 18 DB 20 Acknowledge neg 22 Ready Busy All other pins n c The SETUP program on the CP M diskette must be used to set the CP M LST device to acknowledge the parallel port instead of the second serial port MICRO DECISION REVISION 1 0 PORT ADDRESSES PORT OFS OF6 OF7 Ore OFA OFB OFC OFD OFE OFF FUNCTION MOTOR CHECK PORT ROM ENABLE DISABLE outeenable inedisable VFO COUNT SET PORT MOTOR amp SHIFT CONTROL UPD 765 STATUS UPD 765 DATA ist SERIAL PORT DATA ist SERIAL PORT STATUS 2nd SERIAL PORT DATA fle 2nd SERIAL PORT STATUS MICRO DECISION REVISION 2 0 PORT ADDRESSES OFO ori OF2 OF3 DEA OEB 8253 BAUD RATE GENERATOR CENTRONICS DATA PORT CENTRONICS STATUS PORT read bit 3 ACK 1 write bit 7 stobez 0 read bit 4 busyel All other ports remain the same mdporttf e n wT lass Jt 40 PIN I O CONNECTOR The 40 pin 1 0 connector connects the Micro Decision with the outside world The pin connections for the buss are BRD 1 BWR 3
34. n eau pu au cesso 5 3 Revision 2 0 FeatureS cevscscvcccecvecessscseccece 5 3 1 Parallel POrt c oe wes as e o 5 3 2 Serial POLE i4 we ez Sx eos e sa DSB 5 3 3 40 Pin I O Connector 2220 2222229 9 16 5 3 42 ROM DiagnosticB osse ase sra sa rra 5 3 5 Drive ExpanslOheesese ww OSLO 5 3 6 Disk Drive Connector eco eo mm ww e 9 19 1 MWWHE eee BANDE rar db a e de i TROUBLESHOOTING PROCEDURES oooooooooornnoanonooonnoososo 6 5 1 Tools Required aora aaron cosa D 6 2 Troubleshooting Flowchart ee eee eoe eee ss 6 6 3 Measuring Power Supply Voltages eee eee S 6 6 4 Tips on Troubleshooting Power Supply Problems 6 REPLACEMENT PARTS e eeeeeeeeeeteeeebeeeeeeeeeeeeeesgeeeege 7 CUSTOMER SERVICE BULLETIN INDEX oooocoomoooooonoorooo B SOA YU a WN Fi oe eg 6 NN hd PO NN es 99 og vt rid de d ds LA MAM kd OD be DP se ee ep US C9 UJ G9 CO Lei Od P H KA ka vi 0 sl OU YN k QD oe oe se oe a c oe 0 LI st g 013 E46 0114011 LD Ut LI LN RE 01 LA 1 LA UN TU 9 LIST OF FIGURES emm Mu aum AD umb e LO vm O dr ap AM O MP em vm emt AUD emt em UD as O e ef Om a eem e X Revision A ChasslS 4244 2 Ale 648 REENEN OSs EN AN el Revision B Ch ssiB e wA SU RAN EEN ee ee st Revision C ChassiS 2 44 24 5 49 Ree 2 92 Cover Removal Revision A Chassis nenne au s 2 3 Location o
35. ribed in the Micro Decision User s Guide Refer to the User s Guide for an introduction to the system and operating instructions The intent of this manual is to guide you through module replacements To this end disassembly procedures troubleshooting flowcbarts and SuperSoft s Diagnostics 11 documentation are included If you attempt to perform repairs at a component level you do so at your own risk and with the knowledge that doing so voids any remaining factory warranty on the unit E TABLE O F CONTENTS C gr cue em UP AMD GU UEM UND GUUR gr om CV PU MO US TUA AER EP m cm ee ey Qum dem Ge re pt m e em vg TOOLS REQUIRED FOR DISASSEMBLY 42590 er v oS Pa Ui pan i HP COVER REMOVALwv 4 255 9 s Ud e ee eva e v an ve 2 1 Revision A ChassiS4 xoxo vr EE BOS 2 2 Revision B and C ChassiS ccce eee eee n DOS EN kA DISK DRIVE CONFIGURATION AND REMOVAL cccccvvcccecvecsece 3 1 MD I and MD II Revision A Chassis eneen 3 2 MD III Revision A Chassis eee eee enne 3 3 MD I and MD III Revision B and C Chassis 3 4 MD 11 Revision B and C Chassis ce eee een t te rire e POWER SUPPLY REMOVAL i4 4 ANNA ewe vw eres 4 1 Revision A ChassiS 4 wv W es e we 4 2 Revision B and C Chassis c c eese sect MOTHERBOARD REVISIONS ooooooooooronovorronsansrsnsro 5 1 Revision 1 1 Details esses oeie tesisa 5 2 Motherboard Removal een ei
36. riptions Frame Ground Receive Data Input Transmit Data Output Request to Send Input Clear To Send Output Data Set Ready Output Signal Ground Carrier Detect Output 12V Output 12V Output Alternate Handshake Line 45V Output Receiver Clock Output Data Terminal Ready Input Transmitter Clock Input These signals are available on the printer modem connector only On the circuit board in front of each serial connector is a set of jumper headers labelled JPA and JPB JPA has eight pairs of jumpers for defining tbe terminal port JPB has 13 pairs that define the printer modem port Slip on connectors are used to make the RS 232 pin assignments By changing the positions of some connectors the ports can be configured for use with modems The jumpers select whether the serial connector is set up to talk to DCE or DTE equipment JPA Factory Settings The terminal port can be configured for DCE The signal present on each jumper pin in JPA is shown in Table 5 10 along with the factory setting for the feeding of the signals to the RS 232 connector The reason the pin numbers appear as l 1A is that the board may be silkscreened in either of these two ways 5 9 Part I Section 5 Motherboard Revisions 09 23 83 Table 5 10 JPA Pinouts Terminal Setup RxD to UART RD to terminal USR to terminal DSR to UART DTR from terminal DTR from UART 12V 12V CTS to UART CD from terminal CTS to terminal CTS to UAR
37. s 09 23 83 PJ2 PJ1 o ei E z 9 o o ui o o E Q RAM LOCATION Figure 5 2 Rev 2 0 Motherboard Kohjinsha aa Table 5 4 Rev 2 0 Kohjinsha Bit Map RAM Location RAM LOCATION A Ut BP W iH oO Part I Section 5 Motherboard Revisions 09 23 83 CO t HEES e Ic tesy UN CO pe 785 sl CO OCT Prom CO E 0 CJ L1 Figure 5 3 Rev 2 0 Motherboard Korean Assembled Table 5 5 Rev 2 0 Korean Assembled Bit Map RAM Location RAM LOCATION 0 1 2 3 4 5 6 7 Part I Section 5 Motherboard Revisions 09 23 83 5 3 1 Parallel Port The Micro Decision s unidirectional parallel port is a Centronics compatible port employing a 34 pin edge connector for connection to a printer The data is transferred through a 74LS374 tri State buffer to the connector The addresses for the ports are listed in Table 5 6 Table 5 6 Parallel Port Addresses Data port Status port Read bit 3 1 ACK bit 4 lsBusy Write bit 7 Strobe The signals for the 34 pin edge connector are listed in Table 5 7 Rev 2 0 Kohjinsha and Table 5 8 Korean assembled Rev 2 0 board Table 5 7 Parallel Port Signals Kohjinsha Rev 2 0 Board STROBE neg DBO DB1 DB2 DB3 DB4 DB5 DB6 DB7 Acknowledge neg Ready Busy Even pins 2 24 34 twisted pair ground all other pins n c rart i Section 5 Motherboard Revisions 09 23 83 Table 5 8 Parallel Port Signals Korean
38. tterfly seektest outermost track to innermost track working inward to center and then back out again on a selected disk drive 8 VFO Variable Frequency Oscillator test This test is used for verifying the proper operation of the PLL data separators A frequency counter and a known good Shugart SA200 disk drive is required to perform this test The SA200 disk drive must be installed as drive A Connect the lead of the frequency counter to the test point labeled VCOTP at location E I on the Kohjinsha board or the test point location labeled TPl on the Korean assembled board Insert a formatted diskette in drive A close the door and select the VFO Test from the menu Open the disk drive door and read the frequency The frequency should read 480Khz 30Khz on the Kohjinsha board or 500 Khz 30Khz on the Korean assembled board Ignore intermittent fluctuations in frequency of greater than 10 Khz 9 Boot Selecting item 9 will cause the system to boot a diskette in drive A Remember to remove jumper block after completing diagnostics 5 3 5 Drive Expansion External disk drives C and D are daisy chained from drive B When external drives are added to an MD II or MD III the current 34 pin ribbon data cable must be removed and a new ribbon cable must be installed in its place see Figure 5 11 This new cable consists of two edge connectors and one 2 X 16 header plug One of the edge connectors is connected to drive
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