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'This machine isn't working.'; no tool kit should be without a set of diagnostic questions for instrument troubleshooting.

"This machine isn't working'

If you panic when you hear the words. "This machine isn't working,' you are not alone. Today's instruments are sophisticated and sensitive, capable of performing wondrous jobs and then going down at the worst possible time and for no apparent reason.

Our laboratory serves a 260-bed hospital and a 60-physician clinic. As the lab has become more automated, instrument malfunctions have multiplied. I often used to panic--until I decided that instrument problems were a challenge to my troubleshooting abilities, not an obstacle.

I now strive to think logically and assess a problem one step at a time. When that leads to a solution, job satisfaction also results. When I can't find a solution, I can still say I did my best.

This calm approach involves asking a series of questions designed to get to the bottom of the problem. Here's what I want to know when an instrument isn't working:

1. Is it plugged into the electrical outlet and switched on? Believe it or not, inoperative instruments frequently just lack power. Suspect an unplugged electrical line initially, especially if someone has been cleaning near the instrument.

2. If the instrument is plugged in, switched on, and still not running, is a fuse blown? This is quite easy to check because installed fuses are highly accessible and easy to replace. Keep a supply on hand for every instrument in the laboratory.

3. Is a lamp burned out? If it is the readout source, the instrument may not function without it. To check, you can usually look inside by lifting a lid or removing a cover. Some instruments provide computer screen or printout messages, such as "lamp out,' or they give you a clue, like "decoding error.' The lamp may also be out if the screen is blank, as we have found with one of our spectrophotometers. As with fuses, a ready supply of replacement lamps will minimize downtime.

4. Which step was being performed when the instrument went down? This knowledge lets you focus on the area where the problem may have occurred. Let's say the discrete analyzer is down. Was a specimen loaded into it? A test pack? Did the pack pass the filling station? Was it filled? Did it go on to the processing chamber? What step was last visible?

5. What was on the display or printout when the instrument stopped running? Many computerized instruments relate their problems in code. The message section of the service manual will tell you what a code term means.

6. Is there enough reagent? On some instruments, reagent levels may not be discernible while tests are being run. Instruments with alarm systems alert technologists to insufficient reagent volume. Otherwise, you should check levels before running the first tests of the day and continue to do so every three or four hours as test volume requires. Lines and membranes may become brittle and break when allowed to dry because of inadequate reagent volume.

7. Are there clots or fibrin strands in the specimen? Clots in serum can plug a sample needle or line. Run a wire stylet through the sample needle, or change the needle or the sample line. Regular use of a filtering tube on samples greatly reduces the chances of clogging.

8. Did the instrument blank out and give negative numbers? If the specimen is moderately to heavily lipemic, instrument results will often be of poor precision and accuracy. Fatty specimens should not be used unless you have a good method for clearing lipemia, such as ultracentrifuging.

9. Is there adequate specimen? Check either the sampling system of the instrument--sample cups, for example--or the hand-operated pipet.

10. Was there a current fluctuation in the laboratory? Did the lights dim or the power go off for even a few seconds? Instrument computer boards are often extremely sensitive to interruptions in electrical power. Computerized equipment should be on dedicated lines or have a power surge unit that protects against damage caused by intermittent power.

If a power surge causes instrument failure, refer to the service manual for instructions on how to perform an electronic check. The manual will direct you to throw various switches in order to determine whether a computer board is malfunctioning. For example, if the manual indicates that the readout should be 0 to -40 and yours is 0 to 40, then there's a bad board. Which one? Usually this requires a phone call to the service center, but at least you have pinpointed the problem area.

Voltage checks are also useful for electronic troubleshooting. If you are experienced in using a voltmeter or have a bioengineer in your institution, check the voltages of boards and power supplies and relay this information to the service center.

If you still haven't solved the problem after asking these questions, refer to the instrument manual's troubleshooting section. Diagrams will help identify the malfunctioning part or area of the instrument.

Give as much information as possible to service personnel, including instrument name, model number, and serial number. Relate the problem as precisely as you can. For example, report that "It's the brass piece located in the filling station to the right hand of the exit tray,' and not "The thingamajig on the front of the machine is going crazy.'

When the service center tells you that a part is needed to repair the instrument, have it sent to the laboratory and install it yourself whenever possible. Many parts are modular and simple to install. Power supply units, for example, are self-contained. It's matter of unplugging the old and snapping in the new. The lab realizes substantial savings when a technologist does the repair.

To order a part, you usually need to convey this information: instrument and part names, model and serial numbers, serial number of part, and the name, address, and telephone number of the hospital or lab. Indicate exactly who should receive the part (and let your receptionist know that you are waiting for a package). Finally, specify method of delivery. If a backup instrument is down, the lab can probably can wait for the part to arrive by regular mail. But if tests cannot be performed without the instrument, request overnight delivery from the service center.

Despite vigorous troubleshooting efforts, there are times when laboratory personnel simply cannot repair instruments themselves. Then the laboratory has two choices: Ask a service representative to come to the lab, or ship the instrument to the service center. Sending an instrument out for repair has its own problems, such as packing it with proper protective material, trusting that it will get to its destination, and waiting for it to be repaired. The process can take weeks or months, so it's best not to send out an instrument if you lack a suitable backup method.

Preventive maintenance records assist the troubleshooter by pointing up past instrument problems, so check them when troubleshooting. Fellow staff members can also help. Train all instrument operators to do minor tasks such as checking reagents, wiping down the instrument, changing fuses, and replacing lamps. Instruct at least one or two other people in major troubleshooting --voltage and electronic checks and replacing computer boards, needles, and lines.

It's important to remember that problems with new instruments often surface in the first six months after installation. Shipping may cause some of the difficulties, particularly with computerized units. An instrument that blows boards at first is likely to work fine after being in place for a while.

Experience is one of the best troubleshooting teachers. If you are just beginning, don't be discouraged by the amount of time consumed. Sometimes it has taken me hours to get an instrument operating. But with each new problem and each recurring one, I have learned to troubleshoot more easily.

The next time you hear, "This machine isn't working,' think of the satisfaction awaiting the person who gets it running again.
COPYRIGHT 1986 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1986 Gale, Cengage Learning. All rights reserved.

Article Details
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Author:Johnson, Judy E.
Publication:Medical Laboratory Observer
Date:Aug 1, 1986
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