The Accutach Tachometer Calibrator/Tester Rev. 2
Contents
1. you just blow a fuse in your car If you are unlucky you may burn your car garage and house down It s a good idea to put a rag or some other electrical insulator under the alligator clip Also needless to say don t do electrical work around gasoline fumes Double check the power connections before turning on the ignition key You can now go to the section entitled Using the Digital Signal Generator Program Warning The CSC unit dissipates 9W at 12V so it gets quite warm if used for a long period of time with a 12V supply This is normal but you should exercise care when handling a hot CSC unit to avoid discomfort or injury It is a good idea to disconnect the CSC unit from power when it is powered at 12V and is not being used Connecting the CSC to a direct coupled tachometer In the car A direct coupled tachometer can also be tested and the calibration checked while it is still in the car Some may even be calibrated while still in the car The first step is to turn the car s ignition key off and disconnect the tachometer wire from the coil or electronic ignition unit DO NOT try to run the calibrator tester without disconnecting the tachometer wire from the coil or you could destroy the CSC unit With a negative ground car clip the red lead with a red clip to the car s positive power source ground on on positive ground car and clip the black lead with a black clip to a the negative power source ground on a nega2. 12V the more the needle is deflected and the less time the waveform is at 12V the less the needle is deflected ee e a eee el Low RFM Lite Needle Deflection High RPM Lot of Needle Deflection To calibrate the meter you want to drive the tachometer with a very accurate known signal at the correct frequency for the RPM reading that you want on the meter Once you are driving the tachometer with the accurate frequency you can adjust the needle deflection to the proper place by turning the calibration pot R5 The tachometer can only be calibrated at one RPM After that all you can do is check to see how close you are at other RPMs Page 24 The Accutach Tachometer Calibrator Tester User s Manual It is possible to recalibrate the 7 000RPM Alpine 4 cylinder tachometers to work in V8 Tigers using this method The most common failure modes I have seen are failure of the main timing capacitor C2 Failure of this cap has caused tachometers to be erratic temperature sensitive or just plain dead If you suspect your tachometer to have this problem locate the capacitor carefully unsolder the capacitor and replace it with a new one I have not been able to locate a supply of 0 25uF capacitors but available 0 22uF to 0 27uF capacitors work fine I have yet to come across a tachometer with a failed transistor but they are rumored to cause problems as well The other major failure mechanism I have seen is a broken meter spring The meter need
3. 21 Bench power supply Considerations c istvsiccsseccccsassccsssesseracsvasncaeenedvedecavecscdednbeneesbeeseatees 22 Tachometer background information Smiths cess esseceseeeseeeeseeceaeceeeeeeeeesneeesaeen 23 Tro bl shootin t eraan a TE E E de beneesd on ouane a AEA duet a a 25 How to get product SUPPOMl ccs sasessisagesdacsyeosaessuseadseseaeaasdsoven doa syadeove Soceectecweradeusdsee den spevaands 29 Disclaimer This calibrator tester was designed to work with inductively coupled electronic tachometers such as the Smiths type found in Jaguars Sunbeam Alpines Sunbeam Tigers and most other vintage British sports cars It was also designed to work with direct coupled tachometers as those found in 94 98 Ford Mustangs or 88 91 Honda Civics This calibrator tester was designed using techniques designed to minimize any chance of causing any damage to your tachometer and or PC However Accutach is not responsible for any damage that might occur through the use or misuse of this product Before you use this product please check the Accutach web site www accutach com to see if there is any last minute information you may need to safely use this product Feel free to contact us before using this product on any tachometer should you feel unsure Page 1 The Accutach Tachometer Calibrator Tester User s Manual The Accutach Tachometer Calibrator Tester is designed to simulate high current automotive ignition signals for the Smiths tachomete
4. Manual Using the Digital Signal Processor Personal Computer Software Double click on the generator exe icon in the folder you extracted it to You will see a window that looks like this Digital Signal Generator Freeware of http heliso tripod n SS Square Wave Sweep Lin Settings D A Output Add Exit You will only need to use five of the buttons Square Wave Sweep Lin Settings D A Output Add and Exit Click on the Settings button You will see a window that looks like this Type Sine wave X Sample Fre 11025Hz 44 Signal Len 100000 lt 1000000 Frel 1000 00000 Time Fre2 0 000000 185 Page 13 The Accutach Tachometer Calibrator Tester User s Manual Click on the down arrow next to the Type field and you will see a window like this Beat wave Sweep sine wave linear Sweep sine wave log Select Square Wave You will see a window that looks like this te E Sample Fre 11025Hz yy Signal Len 100000 lt 1000000 Frel 100 000000 Time Fr 0 000000 Enter 100 0000 in the Frel box and click on the Set button There is no reason to change any of the other default settings You will see a window that looks like this don t worry about the 0 1 in the Fre2 box Type Square wave Sample Fre 11025Hz yy a 100000 lt 1000000 Click on the Close button Page 14 The Accutach Tachometer Calibrator Tester User s Manu
5. as it is very easy to damage it or the bezels I have not been able to locate a source for the seals so I just try to be very careful and reuse what I can with what s left of the seals I always use a lint free cloth and glass cleaner to clean the glass while the tachometer is apart Page 23 The Accutach Tachometer Calibrator Tester User s Manual Once the meter face is exposed be very careful not to mar or get finger prints on the face or break the needle The next step is to remove the tachometer innards from the case There are four screws on the back of the case two of which are recessed in holes in the case and two of which are not The two in the recessed holes hold the innards of the tachometer together so don t take them out Put the tachometer case face down on the bench While pinching the U bracket stud with one finger and the power spade lug with another to hold up the tachometer innards remove both of the non recessed screws The tachometer innards are now being held in the case by your two fingers Pick up the case and cup your other hand under the face of the case Carefully let the stud and spade lug slide out of your fingers and catch the face of the tachometer by the edges in the cup of your hand You can then pull the case off of the tachometer innards and turn it over You are now ready to calibrate or debug the tachometer This is a good time to slide a shield under the needle to shield the face and repaint the ne
6. followed by the Close Button Click on the D A Output button and then click on the Circle button to start the signal generator running again IE Digital Signal Generator Freeware of http heliso tripod bcl KKA TA e e e x u If you unplug the CSC unit from the headphone jack you will hear a higher frequency 533Hz buzz Page 16 The Accutach Tachometer Calibrator Tester User s Manual Sweeping the Needle with a PC It is often a good idea to sweep the needle to see if there are any RPMs at which the tachometer behaves strangely To set up a sweep from one RPM to another click on the Settings button to bring up the settings window Sample Fre 11025Hz Click the Set button followed by the Close button The signal generator is now set to sweep the needle Click on the D A Output button to bring up this window Select sine wave to sweep speedometers and square wave to sweep tachometers Click on the Single button to sweep the needle once or click on the Circle button to sweep the needle repeatedly Page 17 The Accutach Tachometer Calibrator Tester User s Manual Using the Android FuncGen Signal Generator Software Tap on the FuncGen icon You will see a window that looks like this al 3 39 Pm uncGen Frequency AAO nny S e Prequency m d Settings ae Start Square Wave Sweep toggle Frequency You will only need to use five of the f
7. pulses caused by the car s ignition circuit into the inside of the tachometer The timing of those current pulses are used to drive the tachometer The Accutach Tachometer Calibrator Tester is designed to calibrate these type of tachometers While this calibrator tester will work with any inductively coupled electronic tachometer it was developed and tested with Smiths tachometers from the mid 1960 s These tachometers were used in Sunbeam Tigers and Alpines as well as in Shelby Cobras and many other British cars of the period Since this is the tachometer I ve had the most experience with this is the tachometer I will describe in detail The Smiths tachometer must be disassembled in order to calibrate or repair it Carefully rotate the chrome bezel until the tabs on the bezel line up with the slots on the case This can be a very difficult job if the seals have aged badly and stuck Whatever you do DON T pry up the tabs on the bezel or you ll ruin it We use a pair of plastic strap wrenches with rubber straps to rotate the tough bezels Don t tap the bezel edge as the meter is very fragile Once you get the chrome bezel off the tachometer the face glass and inside bezel must come out if they didn t come out with the chrome bezel Carefully pry the inner bezel from the case It is not necessary to separate the glass from either bezel if it is stuck to one of them Be careful prying on anything especially if the glass is still in place
8. the red cliplead to the tachometer s ignition connector Double check the power connections before turning on the power supplies You can now go to the section entitled Using the Digital Signal Generator Program Page 10 The Accutach Tachometer Calibrator Tester User s Manual Connecting the CSC to a direct coupled 88 91 Honda Civic CRX tachometer On the bench The Honda tachometer signal must be at least 5 7V in magnitude and it can easily handle 12V So you can use one 12V power supply to calibrate these tachometers Locate the tachometer power ground and signal terminals Connect the power supply positive lead to the red CSC unit power lead and the tachometer power terminal Connect the power supply negative lead to the black CSC unit power lead and the tachometer ground terminal Connect the CSC Unit tachometer lead opposing colors lead to the tachometer signal terminal We used red black and green extension clipleads for power ground and signal for convenience Connecting the CSC to a direct coupled 94 98 Ford Mustang tachometer On the bench The Mustang tachometer signal must be at least 5 4V in magnitude and it can easily handle 12V So you can use one 12V power supply to calibrate these tachometers Locate the tachometer power ground and signal terminals Connect the power supply positive lead to the red CSC unit power lead and the tachometer power terminal Connect the power supply negative lead to the black CSC
9. For your reference here are the schematics for the tachometer from the Series 3 E type Jaguar from 1971 to 1975 1971 1975 Series 3 E type Jaguar Tachometer Schematics 64uF 15V Mark Olson 2012 Battery Voltage Green BLU GRY BLK o Lo x o z 2 ra an 5 BRN 2 i 2 C GRN z 65 s O ORN 2 5 U1 YEL TI VIO MIC7 C gali RED ON a R1 D1 R3 gt 2 6 T 290 LL 4 7K BLU RED 5 7 WSs mS GRY WHT z BLK BRN o YEL i YEL a ORN Z RED MIC7 C RED BLK 7 H o lt a YEL 18 i TS RED 2 17 BLK 30 16 4 l 5 ia J Ground Besa Case op View Page 27 The Accutach Tachometer Calibrator Tester User s Manual How to get product support The Accutach Tachometer Calibrator Tester is a very robust design and should give you years of very good service If it breaks due to anything other than flagrant abuse I ll repair it or replace it at my option for five years after purchase You only need to pay the shipping and handling both ways Before you send it back write or give me a call to see if we can debug things first I can be reached for support in the following ways US Mail Mark Olson 5467 Glennan Ct San Jose CA 95129 Internet molson accutach com Day Phone 1 408 357 3541 Page 27
10. The Accutach Tachometer Calibrator Tester Rev 2 New and Improved to Work with Modern Computers User s Manual Revision 2 3 Copyright 2011 2012 Mark Olson www accutach com The Accutach Tachometer Calibrator Tester User s Manual Table of Contents Table of COM i sccocsieteases nesis peiteseab eee ctunees Megat nee deten aa a ieni Sa a tE E Snara 1 System REQUITEIIENIS sorena o R a EE Ea S AAS EE TEO E E EEEE S ERES 2 Identifying Hardware Revisions sssessesssesesesessseessressersseresseessseesseesstesseeesseeesseesseesseesset 2 Installation Guide snsc isinisisi ieiii nasri a ete atic re ae tee eure lees 3 Selecting a Power SUPPLY sissscsciasseccivavesenstevsasacaisesen iii a E E TEE EEEE E RE 5 Connecting the CSC unit to an inductively coupled tachometer In the car 00 5 Connecting the CSC to a direct coupled tachometer In the car eessseeeeeerereeeee 5 6 Connecting the CSC to an inductively coupled tachometer On the bench eee 8 Connecting the CSC to a direct coupled tachometer On the bench ceeeeeeeeeeeeee 10 Connecting the CSC to a Honda Mustang Tachometer amp Speedometer On the bench 12 Using the PC Digital Signal Processor Software ee eesceseeeseeeneecesecsseeeseeeeaeecaeenes 14 Using the Android FuncGen Software cceccesseesseceneceeeeeeeeeeseecaeceeeseeeeeaeecaeenes 18 Testing Debugging or Calibrating Tachometers amp Speedometer eeeeeeeeeeeeeeees
11. V to 12V power supply for the CSC unit Attach the CSC unit s black cliplead to the supply s ground connection If the tachometer is a negative ground unit attach the 12V tachometer power supply to the bayonet connector on the back of the case and attach the tachometer power supply ground to the case or a ground connection if the case is removed If the tachometer is a positive ground unit attach the tachometer power supply ground wire to the bayonet connector on the back of the case and attach the 12V tachometer power supply to the case or an internal ground connection if the case is removed Page 7 The Accutach Tachometer Calibrator Tester User s Manual Attach the red cliplead to the 5V or 12V power supply for the CSC unit Attach the CSC unit s black cliplead to the supply s ground connection If the tachometer is a negative ground unit attach the 12V tachometer power supply to the bayonet connector on the back of the case and attach the tachometer power supply ground to the case or a ground connection if the case is removed CSC Unit Positive Lead CSC Unit Ground Lead Power Supply Ground Lead Power Supply Positive Lead Screws attach tachometer to case If the tachometer is a positive ground unit attach the tachometer power supply ground wire to the bayonet connector on the back of the case and attach the 12V tachometer power supply to the case or an internal ground connection if the case is removed Power Sup
12. al You will see a window that looks like this E Digital Signal Generator Freeware of http heliso tripod Click on the Add button until the Waveform reaches its maximum size maximum audio volume Click on the D A Output button You will see a window that looks like this Unplug the CSC unit from the PC s headphone jack Click on the Circle button This will cause the PC to make a continuous 100Hz buzzing sound from the speakers clicking the Single button will cause the PC to make a 100Hz buzzing sound for 18 seconds only Make sure you maximize the volume before plugging the CSC unit s plug back into the PC s headphone jack At this point you can power up the tachometer and the CSC unit You will be driving the tachometer with a 100Hz signal Single Circle nl Click on the Close button to stop the signal To restart the signal click on the D A Output button and then the Circle button again Page 15 The Accutach Tachometer Calibrator Tester User s Manual You must stop the signal by clicking on the Close button prior to changing the frequency of the signal You will again see a screen that looks like this Digital Signal Generator Freeware of http heliso tripod 0 WII DIPI Dele eI Square wave Sample Fre 11025Hz 4 Signal Len 100000 lt 1000000 Frel 533 33333 D Enter 533 33333 in the Frel box then click the ue
13. cle speed signal such as that in 1994 1998 Ford Mustangs The Mustang speed signal generates 8000 pulses per mile Since there are 3600 seconds in an hour and 8000 pulses in a mile calibration frequencies can be calculated with this formula Freq 8000 3600 MPH 2 22222 MPH This table tells you the frequencies to enter into the Digital Signal Generator in order to simulate VSS signals at different speeds MPH Freg Hz MPH Freq Hz to 2 22222 9o 200 20 44 aaaaal 100 222 2222 30 66 66667 110 244 4444 40 88 88889 120 266 6667 50 a1aata 130 288 8889 60 133 3333 140 311 111 70 155 5556 150 333 333 80 177 7778 _160 355 555 To calibrate a speedometer select the frequency that corresponds to the speed you want and start the signal generator Power up the speedometer and the CSC unit The speedometer needle should move somewhere on the speedometer face At this point remove the speedometer s needle and replace it on the speedometer shaft so that it points to the correct speed for the frequency you chose You can drive the tachometer up to 180 degrees from the 0 MPH mark without problem If you try to drive it much more than 180 degrees the needle will not move If you drive it too close to 180 degrees the needle will go there but peg the speedometer to the bottom of the pin when you turn off the calibrator It can be difficult to get it to move back to 0 MPH so
14. d car or motorcycle battery makes a very good well regulated power supply Most tachometers use a 12V supply voltage although some may use a 6 volt supply Battery chargers are not well enough regulated unless they are connected to a charged car of motorcycle battery Direct coupled tachometers that are powered by 12V but expect a signal that is no larger than 0 5V will require both a 12V power supply for the tachometer and a 5V power supply for the CSC unit The CSC unit will not work if powered by less than 5 volts and may be damaged if powered by more than 12 volts It is a good idea to disconnect the CSC unit from power when it is powered at 12V and is not being used It generates nearly 10 Watts and it gets quite hot Connecting the CSC unit to a power supply There are three test leads coming out of the CSC unit There is a black lead with a black clip negative power a red lead with a red clip positive power and a lead with one color and a clip of the other color That lead is the directly coupled tachometer signal Connect the CSC unit red lead with the red clip to the positive terminal of the power supply and connect the CSC unit black lead with the black clip to the negative terminal of the power supply Be sure to check the tachometer to see if it is a positive or negative ground unit before connecting it to its power supply and connect it accordingly Do not connect the CSC unit black lead with a red clip o
15. e Now you will need to extract the program file from the compressed file If your computer does not have a rar file extractor you can download the program FreeRARExtractFrog from http download cnet com Free RAR Extract Frog 3000 2250_4 10804840 html Follow the instructions to install it Once you have the Digital Signal Generator rar file saved and have a rar file extractor extract the generator exe file from the generator rar file and save it in any folder you d like on your computer We recommend saving it to your desktop Once you have the generator exe file on your computer there is no further installation required The software will run when you double click on the generator exe file icon Connecting the CSC to the personal computer The Accutach Tachometer Calibrator Tester Rev 2 was designed to plug into a standard 3 5mm stereo headphone jack on a personal computer First make sure that your audio is not muted and the volume is set to maximum Then simply plug the 3 5mm stereo headphone CSC plug into the jack Page 3 The Accutach Tachometer Calibrator Tester User s Manual Android Installation Guide This section of the instructions will tell you how to install the Digital Signal Generator software on your Android device and how to connect the Tachometer Calibrator Tester CSC unit to your computer Installing the software on the Android device Open a browser and navigate to https play google com st
16. e CSC Current Switching Circuit Unit 0 1uF capacitor for electronic speedometer calibration The following items are NOT included with the Calibrator Tester Power supply Intel compatible personal computer or Android device Digital Signal Generator software The power supply and personal computer can be purchased on line or at a local electronic or computer retail store The Digital Signal Generator software can be downloaded from http heliso tripod com download generator dsg htm Should this link ever fail please check the Accutach web site www accutach com Identification of Hardware Revisions The first revision of the Accutach Smiths Tachometer Calibrator can be identified by its 9 pin D serial port connector Revision 1 is now obsolete The second revision of the Accutach Smiths Tachometer Calibrator can be identified by its 35mm stereo audio plug Page 2 The Accutach Tachometer Calibrator Tester User s Manual PC Installation Guide This section of the instructions will tell you how to install the Digital Signal Generator software on your personal computer and how to connect the Tachometer Calibrator Tester CSC unit to your computer Installing the software on the computer Open a browser and navigate to http heliso tripod com download generator dsg htm Click on the Press here to download link Save the file generator rar to a folder of your choosing A tar file is a compressed file similar to a zip fil
17. e the ignition for one half of the cylinders during each revolution of the crankshaft So an 8 cylinder engine fires 4 times per rev a 6 cylinder engine fires 3 times per rev a 5 cylinder engine fires 2 5 times per rev and a 4 cylinder engine fires 2 times per rev Since there are 60 seconds in one minute the tachometer signal frequency in Hz can be calculated using the following formula Freq RPM 60 the number if ignition events per revolution 4 cyl freq RPM 30 8 cyl freq RPM 15 5 cyl freq RPM 24 10 cyl freq RPM 12 6 cyl freq RPM 20 12 cyl freq RPM 10 This table tells you the frequencies to enter into the Digital Signal Generator in order to simulate ignition signals at different RPMs 1500 2000 2500 25 3000 30 3500 35 4000 40 4500 45 5000 50 5500 55 6000 6500 65 7000 70 7500 75 8000 80 8500 sooo soo 375 asof eoo 75o 900 9500 To calibrate a tachometer select the frequency that corresponds to the RPM you want for the engine the tachometer is for and start the signal generator Power up the tachometer and the CSC unit The tachometer needle should move somewhere on the tachometer face At this point turn the tachometer s calibration potentiometer until the needle points to the correct RPM for the frequency you chose Page 20 The Accutach Tachometer Calibrator Tester User s Manual Testing Debugging or Calibrating Speedometers Many electronic speedometers depend on an vehi
18. edle if you can find appropriate paint My artistic talents aren t very good so I never try that step myself Reassembly is the reverse of this process Electronically the Smiths tachometer is a relatively simple two Germanium transistor inductively coupled electronic tachometer The following diagram shows the schematic of the tachometer The two transistors together form a monostable multivibrator or one shot Normally the collector of QI is at 6V An ignition pulse couples through the transformer to trigger a one shot voltage pulse to 12V on the collector of Q1 for a set amount of time Every time an ignition pulse is detected through the transformer the collector of Q1 will pulse from 6V to 12V for a fixed amount of time While the collector of Q1 is at 12V the top of the meter is held at 6V by the Zener diode so current will flow through the meter causing the needle to deflect The width of the voltage pulse is determined by the combination of the 0 25uF capacitor C2 and the combination of resistors R3 R4 and pot R5 The one shot is triggered by every ignition pulse so the voltage waveform looks like a series of pulses when the engine is running Since the pulses are fixed in width and the frequency of the pulses is determined by the engine speed the ratio of the time the waveform is at 12V vs 6V goes up with increases in engine speed and down with decreases in engine speed The way the meter works the more time the waveform is at
19. er connections before turning on the power supplies You can now go to the section entitled Using the Digital Signal Generator Program Connecting the CSC to a direct coupled tachometer On the bench You will need to obtain some sort of power supply in order to test or calibrate tachometers on the bench Please refer to the section entitled Selecting a Power Supply for a discussion of suitable and non suitable bench power supplies When removing the tachometer from the dash and or the instrument cluster be careful not to lose any of the parts The same care should be taken if the tachometer needs to be disassembled for calibration Attach the red cliplead to the 5V or 12V power supply for the CSC unit depending on the input requirements of the tachometer Attach the CSC unit s black cliplead to the supply s ground connection If the tachometer is a negative ground unit attach the tachometer power supply to the tachometer s power connection and attach the power supply s ground to the tachometer s ground I do not know of any positive ground direct coupled tachometers but if you have one attach the power supply ground wire to the tachometer s power connector and attach the 12V power supply to the case or an internal ground connection if the case is removed 1971 1975 Series 3 E type Jaguar tachometers are all negative ground tachometers and should be connected as shown on the previous page Attach the black wire with
20. it is not advised to calibrate the speedometer above 180 degrees from the 0 MPH mark Page 21 The Accutach Tachometer Calibrator Tester User s Manual Bench power supply considerations On the bench you will need a good well regulated power supply to power the tachometer and the CSC unit The tachometer requires a well regulated 12V supply while the CSC unit requires a 5V to 12V supply I don t have power consumption specifications for the tachometers but they don t seem to require too much current to operate However it is very important that the 12V supply to the tachometer be a very clean steady 12V Ripple or noise on the power signal will confuse the tachometer completely A 12 battery charger can t be used for example because there is far too much ripple in the power supply and it can t respond well to sudden changes in current The CSC unit uses nearly 10 watts when it is not being driven by the computer It is a good idea to disconnect the CSC unit from power when it is powered at 12V and is not being used When the calibrator tester is driving the tachometer with a signal the CSC unit draws a maximum current of 1 4 Amp if powered by a 5V supply to 1 2 Amps if powered by a 12V supply Clearly the CSC unit will run considerably cooler when powered by a lower voltage supply A charged 12V car battery is a very well regulated power supply for bench testing tachometers An ideal bench setup is a small regulated 12V sup
21. ng period of time with a 12V supply This is normal but you should exercise care when handling a hot CSC unit to avoid discomfort It is a good idea to disconnect the CSC unit from power when it is powered at 12V and is not being used Page 6 The Accutach Tachometer Calibrator Tester User s Manual Connecting the CSC to an inductively coupled tachometer On the bench You will need to obtain some sort of power supply in order to test or calibrate tachometers on the bench Please refer to the section entitled Selecting a Power Supply for a discussion of suitable and non suitable bench power supplies When removing the tachometer from the dash be careful not to lose the knurled nut lockwasher and U shaped metal bracket that hold the ignition wire loop to the back of the tachometer Leave any plastic material holding the ignition wire in a loop on the wire Be sure to take the U bracket with the tachometer as they are required for calibration Do not lose the nut and lockwasher that holds the bracket First put one leg of the tachometer s U shaped bracket through the loop in the CSC unit s red cliplead wire as shown in the drawing we Loop Pg cise x A ai AI 0 CA Gi CHI S wee 7 RK P Pa U bracket Pa U bracket Correct Loop Connection Incorrect Loop Connection With the wire loop through the U shaped bracket attach it to the back of the tachometer Attach the red cliplead to the 5
22. ore apps details id com crescendosystems afg amp hl en Click on the Install link The FuncGen Signal Generator application will be installed on your Android device The software will run when you tap on the FuncGen icon https play google com store apps details id com crescendosystems afg amp hl en Connecting the CSC to the Android device The Accutach Tachometer Calibrator Tester Rev 2 was designed to plug into a standard 3 5mm stereo headphone jack First make sure that your audio is not muted and the volume is set to maximum Then simply plug the 3 5mm stereo headphone CSC plug into the jack If your Android device is a cellular phone you must buy a 2 5mm cell phone jack to 3 5mm stereo jack adapter Page 4 The Accutach Tachometer Calibrator Tester User s Manual Selecting a Power Supply Most of the time you will need a single well regulated power supply that can supply up to one amp of current in a square wave This is true for all inductively coupled tachometers and for direct coupled tachometers that expect a signal that will go from 0 volts to the voltage that powers the tachometer For example a 12 volt inductively coupled Smiths tachometer will need only a single 12V power supply This is true for both negative and positive ground tachometers Direct coupled tachometers that expect an input that goes from 0 volts to the power supply voltage for example 12V then you will only need a single power supply A charge
23. ply Positive Lead CSC Unit Ground Lead CSC Unit Positive Lead Power Supply round Lead Page 8 The Accutach Tachometer Calibrator Tester User s Manual Connecting the CSC to a direct connect Smiths tachometer eg Series 3 E type Jaguar Attach the red cliplead to the 12V positive power supply regulated or battery connection Attach the CSC black clip lead to the 12V power supply ground negative connection Attach the 12V tachometer power supply to the Tachometer power connector Green wire in the case of the S 3 E type Jag and attach the tachometer power supply ground to the case or a ground connection if the case is removed Attach the CSC unit s Signal red lead with a black clip or vice versa to the tachometer input connection White wire with Blue stripe in the case of the S 3 E type Jag You can do the same connections at the ballast resistor connector to check the calibration in the car using any chassis ground Note the hole for accessing the calibration pot If your tachometer has this hole you do not need to disassemble the tachometer to calibrate it Battery power for The CSC unit and the tachometer Black Wir RE A Note that temporarily added a ground lug to the PCB mounting screw to make it easier to ground the tachometer for debug and calibration Ground for the CSC unit and the tachometer Battery power for The CSC unit and the tachometer Page 9 The Accutach Tachomete
24. ply for powering the tachometer and a separate larger well regulated variable supply for powering the CSC unit The power supply in your computer should NOT be used as the calibrator tester could easily overload your supply or inject noise into the system that could cause your computer to have severe problems Page 22 The Accutach Tachometer Calibrator Tester User s Manual Tachometer background information This section is intended to give you some background information on tachometers to enable you to determine if the Accutach Tachometer Calibrator Tester can help you calibrate your tachometer help you do calibration and if you are real adventuresome help you repair broken tachometers I know of two types of electronic tachometers in cars inductively coupled and direct coupled Direct connect electronic tachometers have a direct electrical connection to the ignition circuit These tachometers use voltage signals in the ignition circuit to drive the tachometer Since there are so many types of direct coupled tachometers I can t describe them all Most of them need to be disassembled in order to calibrate them You need to look for an adjustment pot or variable resistor used to calibrate the tachometer You also need to ensure that a 12V signal on the input will not hurt the device The inductively coupled type of tachometer uses a one turn loop of the ignition wire as the primary side of a transformer that couples the current
25. r Calibrator Tester User s Manual If the Smiths tachometer needs to be taken out of its case for calibration or repair do not pry the metal tabs on the bezel or the bezel will never fit properly on the case again Twist the bezel in either direction until the slots in the case line up with the tabs on the bezel The bezel trim ring gasket and glass can then be pulled off the front of the case It can be very difficult to break the bezel free We use a pair of plastic handled rubber strap wrenches to get the bezel to rotate on the case To remove the tachometer from the case hold the power lug and U bracket stud between two fingers to hold the tachometer in the case as you remove the two tachometer mounting screws on the rear of the case Once the two screws are removed cup your other hand under the front of the tachometer to catch the face by its edges as it falls out of the case when you release your two fingers from the back Try not to let the weight of the tachometer fall on the needle For inductively coupled tachometers the wire loop is set up the same with the tachometer out of the case as it is in the case The power lug is connected the same way out of the case as it is in the case The case ground connection is made to the end of the large resistor that connects the two tachometer circuit boards together Use the end of the resistor that is connected to the trace that goes to the metal frame of the tachometer Double check the pow
26. r the red lead with a black clip to anything unless you are driving a directly coupled tachometer See the directly coupled tachometer sections below to see how to connect that lead Connecting the CSC unit to an inductively coupled tachometer In the car An inductively coupled tachometer such as the Smiths tachometer used in Sunbeam products can be tested and the calibration checked while it is still in the car The CSC receives its power from the ignition wire The first step is to turn the car s ignition key off and disconnect the ignition wire from the coil DO NOT try to run the calibrator tester without disconnecting the ignition wire from the coil or you could destroy the CSC unit With a negative ground car clip the red lead with the red clip to the ignition wire and clip the black lead with the black clip to a convenient ground With a positive ground car clip the black cliplead to the ignition wire and clip the red cliplead to a convenient ground Do not let the third clip the clip with one color and the lead with the other color touch anything or you can destroy the CSC unit We normally leave this lead clipped to the base of its own lead to keep it safe and out of the way Page 5 The Accutach Tachometer Calibrator Tester User s Manual Warning Make sure that the ignition wire and the red alligator clip do NOT touch ground during testing and calibration or whenever the ignition switch is on If they do you ll be lucky if
27. r used in many British cars of the 1960s and 1970s It is also designed to simulate the voltage driven tachometer signals in more modern cars such as Ford Mustangs and Honda Civics of the 1980s and 90s It is designed to aid in debugging repairing and calibrating tachometers It can also be used to calibrate some electronic speedometers as well System Requirements The Accutach Tachometer Calibrator Tester is a computer peripheral device It relies on either a Microsoft Windows base personal computer or an Android handheld device running a freeware program to operate The computer must be an Intel compatible Personal Computer running Windows XP or newer The Android Device must run Android 1 6 or newer tested with a Google Nexus 7 tablet Either device must have audio headphone output capability with a standard 3 5mm stereo headphone jack The PC software used in this system is freeware Digital Signal Generator software found at http heliso tripod com download generator dsg htm We have not been able to contact the author but we thank him her for making this software available for free The Android Software used in this system is freeware FuncGen SignalGenerator software from Crescendo Systems found here https play google com store apps details id com crescendosystems afg amp hl en Calibrator Components Your Accutach Tachometer Calibrator Tester consists of the following parts This User s Manual Download from www accutach com Th
28. s to be replaced in this case Replacement meters must be gotten from a parts tachometer As a matter of course the tachometer will have to be recalibrated if any of the parts are replaced All of the Smiths tachometers of this era use the same electronic and mechanical design regardless of number of cylinders positive or negative ground or the make of the car The power and ground wires are reversed between tachometers for positive or negative ground cars The only other thing that changes is the face used on the meters So don t throw away any vintage Smiths tachometers or tachometer parts They can be used to resurrect any other one Troubleshooting This section attempts to explain how to find problems with the Accutach Tachometer Calibrator Tester or your test setup If the tachometer is working in the car with the engine running and you can t get the calibrator to work with a tachometer in the car first double check the cliplead attachment to the ignition wire and the ground if it is an inductively coupled tachometer If you are testing a direct coupled tachometer ensure you have a good power ground and tachometer input connections Make sure they are connected correctly for positive or negative ground Reclip the leads to ensure good electrical connections Make sure the cable from the CSC unit to the personal computer is well seated If the tachometer worked in the car with the engine running and doesn t on the bench check
29. the power supplies and polarities for both the tachometer and the CSC unit Check to make sure you have the loop in the red cliplead through the U bracket correctly on the back of the tachometer if it is an inductively coupled tachometer Reclip the leads to ensure good electrical connections Make sure the cable from the CSC unit to the personal computer is well seated If the tachometer worked in the car with the engine running and it worked in the car with the calibrator tester and it doesn t work on the bench double check the power connections If you are using a 5V supply for the CSC unit try two loops through the U bracket if the tachometer is inductively coupled If the tachometer didn t work in the car and you want to ensure the calibrator tester is working correctly you will probably need to use an oscilloscope on the bench to see if the signal is being coupled through to the tachometer If it isn t There could be a problem with the power connections the loop on the U bracket or the COM port as above If there is no problem there it could be the input transformer or transistor Q1 Page 25 Ignition Wire The Accutach Tachometer Calibrator Tester User s Manual Smiths Tachometer 7 2v Transformer R6 820 R7 150 Transistors Mullard GET 113 Tech tip subst or Mot HEP253 or equiv OC83B eg NTE158 Page 26 Tach Signal The Accutach Tachometer Calibrator Tester User s Manual
30. tive ground car Some more modern tachometers may expect a 0 5V signal in which case you must power the CSC unit with a 5V well regulated bench power supply Clip the black lead with the red clip some units have a red lead with a black clip to the tachometer wire Warning Make sure that the tachometer wire and the alligator clip do NOT touch ground during testing and calibration It s a good idea to put a rag or some other electrical insulator under the alligator clip And needless to say don t do electrical work around gasoline fumes Warning The CSC unit generates a direct coupled tachometer signal that varies between 0 and the voltage that your power supply provides If your direct coupled tachometer needs a 0 5V input signal make sure you use a 5 volt power supply to power the CSC unit If you power the CSC unit with a 12V supply it will generate a 0 12V signal If your direct coupled tachometer requires a 0 12V input signal make sure you use a 12 volt power supply to power the CSC unit Some tachometers can handle either 0 5v or 0 12V signals It is your responsibility to ensure that the signal from the CSC unit to the input of your direct coupled tachometer will not damage it Double check the power connections before turning on the ignition key You can now go to the section entitled Using the Digital Signal Generator Program Warning The CSC unit dissipates 9W at 12V so it gets quite warm if used for a lo
31. unctions Square Wave Frequency Sweep Settings and Start If you don t want to sweep the tach you can simply set the frequency at which you want to drive the tach select Square wave and tap start If you want to sweep the tach you will need to tap the three dot settings icon and then tap the Modulation Parameters icon You will see a screen that looks like this He 3 41PM Linear Sweep in Start sep 1000 Sweep Time Starting Frequency Ending Frequency seconds Page 18 The Accutach Tachometer Calibrator Tester User s Manual To sweep the tach you will need to tap the Linear button to select it Then set the Time to 10 which tells the software to sweep from the minimum frequency to the maximum prequency every 10 seconds Set the minimum and maximum frequencies you want to sweep between FM Index PM Index Stop 1000 Sweep Time Starting Frequency Ending Frequency seconds Linear Sweep Page 17 Tap on the Back icon to go back to the main screen Tap OK if it notifies you that the parameters have been reset Tap Square Sweep and Start to start to sweep the tach needle Note that this sweep sweeps the needle up only not up and then back down again il 3 39 PM Frequency 440 ny S Prequency Settings eel Start Square Wave Sweep toggle Frequency Page 19 The Accutach Tachometer Calibrator Tester User s Manual Testing Debugging or Calibrating Tachometers Four stroke motors fir
32. unit power lead and the tachometer ground terminal Connect the CSC Unit tachometer lead opposing colors lead to the tachometer signal terminal We used red black and green extension clipleads for power ground and signal for convenience Must also be grounded for a V8 tachometer Leave disconnected for a V6 tachometer Signal 12V Power Ground Page 11 The Accutach Tachometer Calibrator Tester User s Manual Connecting the CSC to a 94 98 Ford Mustang Speedometer On the bench The 94 98 Ford Mustang speedometer can be driven by the tester calibrator as well It expects an 8000 pulse per mile AC signal Locate the speedometer power ground and signal terminals There are 2 power terminals for the Mustang Speedometer Connect the power supply positive lead to the red CSC unit power lead and the 2 speedometer power terminals Connect the power supply negative lead to the black CSC unit power lead and the speedometer ground terminal Connect the CSC Unit tachometer lead opposing colors lead to the speedometer signal terminal through a 0 1uF capacitor We used red black and green extension clipleads for power ground and signal for convenience Power Signal Ground 7 DAG LEADED FUEL ONLY gt o 1 4 It is a good idea to disconnect the CSC unit from power when it is powered at 12V and is not being used It generates nearly 10 Watts and it gets quite hot Page 12 The Accutach Tachometer Calibrator Tester User s
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