Related Topics 4.2 Troubleshooting Medical Equipment
Contents
1. always they may have a separate supply pressure flow indicators not on zero a warming of the device On pneumatic hydraulic or vacuum powered units do you hear or see leaks First check for the obvious Is it plugged in both ends of the power cord Is the outlet live Is the power cord good try another one Is there a second power switch on the unit Is the fuse good less than one ohm Is the breaker open push the reset Are the batteries of the proper type installed correctly and charged On some devices there is a voltage compensation switch Check that to be sure it is in the correct setting 110 or 220 V Also some devices have a 50 60 Hertz switch that needs to be in the correct setting see the separate section on frequency adjustments After checking the obvious recheck the device If it still won t power up or it powers up but won t operate correctly you will need to remove the covers Now that the cover is off be very careful In most modern equipment there is more than one power supply in an instrument There are often 5 12 or 15 volt power supplies for the logic circuits 60 to 120 volts for motors and certain displays plus high voltage power supplies up to 150 000 KV You will need to check each of them to see if they are producing the expected voltages Never work alone on a device with the cover off and the power on Double check that you are wearing no jewelry Latex or rubber gloves offer some pr2. switches and controls to be sure that they are correctly positioned and working Before moving any switch or cable take a digital photo of the control panel That way you will be able to go back to the device s original settings Medical Instruments in the Developing World Malkin Assuming that there are no signs of mechanical damage to the device do a self test or calibration on the device This may also give you the error log on the device which must be reviewed and problems noted Look at the manual if you can find it the device history if it exists and the service manual if you can find it to be sure that you have covered what needs to be done to operate the device properly and to determine if the problem has occurred in the past If it is a repeat problem try to determine how it was repaired before If you can get the service manual review it briefly to see if there is a system test or additional self tests that might help Listen to the User Interview the user In most cases the user is not the person who gave you the equipment So ask questions until you find the user of the device You want to talk directly to the user of the device Many problems arise from misunderstanding between the user and the person who gave you the equipment Carefully listen to the user s complaint about device Find out what they see as the problem as What has changed with the outputs or process Is it still within normal r
3. Related Topics 4 2 Troubleshooting Medical Equipment Troubleshooting medical equipment requires patience persistence and a willingness to ask a lot of questions The most common error in troubleshooting is to rush down the wrong path perhaps because of a misunderstanding or misdirection from the staff A willingness to sit back and tack a fresh look at the problem is essential A structured approach helps avoid the most common errors This section presents one possible structured approach to troubleshooting Before You Start Consider safety first Know the hazards that are associated with the device be it electrical mechanical chemical gas or bacterial As a minimum refamiliarize yourself with the equipment s principles of operation and clinical use as described in this book If you are unsure about a hazard consult someone else before beginning User error accounts for a large fraction of the broken equipment in the developing world according to a recent report by Engineering World Health Make sure you know how the device should work before you begin If you can find the manual read it Here are seven steps that you should follow once you are convinced that you are ready to proceed No matter what the problem begin by assessing the piece of equipment It is absolutely essential that you not skip the assessment steps Hours of your time can be spent repairing a problem which never existed in the first place EWH reports that mos
4. anges or not Has the speed of the process changed Has the use of consumables increased It is common for a user or an operator to not know all the functions of a device To avoid looking foolish they will give bad answers to questions outside of their knowledge Also it is common for a user to not tell you a piece of information which is critical to diagnosing the problem The opposite is also true Sometimes the user says they know exactly what the problem is when in fact they are merely guessing You must act as a detective listening to everything but rejecting and accepting facts as you piece together a hypothesis concerning the problem with the equipment Suspect User Error Always suspect user error If you have followed the first steps then you have not as yet opened the device Verify again that the device is in fact malfunctioning Nearly half of the time the device is operating correctly the person is simply using it incorrectly Follow the recommended testing described here If the device is operating as you expect then the problem is user error But what type Attempt to determine if the problem is language incorrect programming or settings or a misunderstanding of what the equipment is capable of doing If the problem is a misunderstanding of the equipment s abilities perhaps you can suggest an alternative If the problem is programming or settings see if you can permanently program or fix the devices function Consi
5. der taping over switches or labeling the correct setting If the problem requires a sequence of steps to resolve or it is a langrage problem Consider creating a cheat sheet that can be attached to the machine This is a simple explanation of the device s operation or the specific operation that is causing the problem Write short direct sentences that describe how to accomplish the task These should be accompanied by drawings wherever possible A digital camera and the internet caf can be used to create a sequence of how to photos Often the photos tell the story better than the words The cheat sheet must be written in the local language Be sure to try out the sheet with the nurse or doctor before attaching it to the device Have them attempt the operation using the sheet and without your intervention If you have to say anything while they attempt the operation then the cheat sheet Related Topics needs revision You cannot rely on the fact that this particular nurse or doctor will always be at the hospital to train the rest of the staff Nurses leave and doctors are often too busy to return to a piece of equipment Suspect Power Supply You may feel that you are ready to open the device There is one more area to test before opening the device the power supply Does the device power up at all The signs that a device is powered up include indicator lamps the screen is lit hearing a fan or motor running though not
6. otection from high voltages Place your probe leads with care to avoid shorting out two lines Proceed slowly Once the cover is off carefully look for dust buildup over fans or vent holes fluid spills loose hardware or worse floating hardware cleaning and correcting as you proceed Make sure all the chassis components are secure Look for signs of heat smoke or burned components Look at any fluids carefully In very old equipment if they are oil based it may be an indication that a capacitor or transformer is leaking or failed Generally if this has happened there will also be signs of heat damage around the failed component Next move on to the circuit boards Are they properly seated Is there dust or spills on them Are there signs of heat buildup Are the components secure on the boards Correct problems as you find them You might look over the solder connections on the boards to be sure that there are no cold joints from previous repairs You might also want to clean the connectors with a pencil eraser the white kind is best Take note of any prior repairs They are clues to current problems Medical Instruments in the Developing World Malkin Power Supply or User Error Somewhere Else If you have ruled out user error and power supply and the problem is not one of the common errors listed in this manual then there are only two other categories of error that are worth your time investigating input and output errors Inp
7. t of the problems you will encounter are related to user error Another quarter are related to power supply issues You should always consider these two possibilities before all else Of the remaining problems the most likely to be solved are those related to the presence or absence of the proper inputs and outputs In other words the problem is related to some other piece of equipment which itself has either a user error or power supply problem Look at the device If at all possible remove the equipment from the patient floor to a quiet clean bench where you can work without interruption Look at the device and all the information that may be around it Are there any notes from the users Is there a description of the problem or is it just labeled broken Is there a name of the person who found the problem Is there an error log on the device Is there evidence of a drop spill smoke heat or other damage If there is evidence of a spill it must be considered hazardous and cleaned by someone trained to handle hazardous spills Spills even non hazardous ones are usually conductive and can cause shorts in the device circuitry Some solutions are very thick and can act as glue that will overload motors on a pump Always follow the Universal Precaution Procedures against infectious agents Next look at any connectors power cords input or output cables to be sure that they are in the correct positions and secure Check the positions of all
8. te display possible Be as creative as possible before abandoning the device due to display errors
9. ut errors can cause an otherwise operating device to appear to have failed Find out where the input comes from Is it a cable electrode probe tissue sample liquid sample What if anything has changed on the input If the device tests blood or tissue samples are they properly prepared Are the samples being presented correctly If the device works on your bench but not on the patient there still may be a device problem but more likely it is an input problem As dumb as it may seem is the patient alive Has the patient s condition changed Is there more movement shaking shivering thrashing around in the bed Did an electrode or other sensor fall off Are the lead wires and cable good The output of a device is its final product In many cases it is a delivered energy a graph or a display In some cases it may be more than one If the device appears to be working but the display is faulty try to do everything you can to devise an alternative display Working equipment in the developing world is too precious to abandon due to display errors In older equipment you can sometimes find a voltage which is proportional to the desired output If this is the case consider displaying this voltage on a multimeter and giving the user a table to convert from volts to the desired units Perhaps a display from another device perhaps even an unrelated device can be used Perhaps the user can live with less resolution or precision making a substitu
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