Testing transistors and diodes in circuit

Sectorseven

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I hate desoldering and am looking for a more efficient way to test these parts. Does anyone have a recommendation for a device that can test these in circuit? Is there a device that will test both or am I looking at two separate tools for this. I've seen the Huntron Tracker mentioned around these forums a few times, but I don't know enough about it yet to just run out and buy one (and in reality it's probably beyond my budget anyway).

I've also read about LCR meters, but again I'm not very familiar with them and don't know if that's what I should be looking for.

I have no problem buying older or used tools, but I am definitely interested in quality products.
 
there are devices that can partially test in circuit BUT they are not always accurate. Other parts connected to the device under test can confuse the readings and give a false result.

There ain't no shortcut I'm afraid!
 
If that's the case, why not isolate the problem area of the board as best you can and just shotgun it?
 
If that's the case, why not isolate the problem area of the board as best you can and just shotgun it?

Technicians take logical measurements based on their experience and can (usually) isolate the problem down to the area in question.

This involves learning, training and many years.....not someething that can be picked up overnight like fitting a door hinge!
 
It feels like everyone is trying to discourage me, lol :)

Let's say for the sake of argument that I'm an amateur hobbyist technician. Am I better off removing parts one by one for testing and not knowing for sure if they will fail under load, or should I get some sort of in circuit tester even though it won't always be accurate?
 
Having a Huntron Tracker can sure help! By seeing an indication on the screen of the Tracker, you can judge whether a component is good, bad, or questionable enough to desolder it and test out of circuit.

Check ebay for a used Huntron Tracker model 1005-B. It's what I use.
 
Well... what kind of things are you troubleshooting? Monitors? Linear power supplies? Switchers? Game PCBs? Which era? In circuit diode and xistor testing really hasn't been much of an issue for me. As a hobbyist (it's fun to me, so time isn't money) I spend more time poring over a schematic to understand how a circuit works, and what might go wrong to cause the problem I'm seeing, than I do randomly testing semiconductors. If I have a reason to suspect a diode or transistor, I look at the schematic and see what else is connected that might effect the measurement if made in-circuit. Knowing common failure modes helps (e.g. diodes tend to fail short). Before it even gets that far, a fair number of diode & xistor failures can be identified by visual inspection.
 
Well... what kind of things are you troubleshooting? Monitors? Linear power supplies? Switchers? Game PCBs? Which era? In circuit diode and xistor testing really hasn't been much of an issue for me. As a hobbyist (it's fun to me, so time isn't money) I spend more time poring over a schematic to understand how a circuit works, and what might go wrong to cause the problem I'm seeing, than I do randomly testing semiconductors. If I have a reason to suspect a diode or transistor, I look at the schematic and see what else is connected that might effect the measurement if made in-circuit. Knowing common failure modes helps (e.g. diodes tend to fail short). Before it even gets that far, a fair number of diode & xistor failures can be identified by visual inspection.


I was thinking more general electronics repair, but as far as arcade repairs go, maybe game PCBs as they seem to have the least documentation.
 
Having a Huntron Tracker can sure help! By seeing an indication on the screen of the Tracker, you can judge whether a component is good, bad, or questionable enough to desolder it and test out of circuit.

Check ebay for a used Huntron Tracker model 1005-B. It's what I use.

Is the Huntron a difficult tool to learn? Any suggested reading (other than the manual)?
 
There is usually an operating manual included with it. It is an excellent manual to read in learning how to use it. There are pictures showing what good and bad components look like on the screen.

Huntron is located in Mill Creek, Washington.

http://www.huntron.com/

You can purchase manuals for Huntron equipment from their online store. Service manuals and operating manuals are all on one CD now to purchase.

http://shop.huntron.com/product.sc?productId=5&categoryId=2
 
I was thinking more general electronics repair, but as far as arcade repairs go, maybe game PCBs as they seem to have the least documentation.

Look trough some manuals from older Atari games, and be sure to check out The Book by Atari. Between those, you will find really good documentation on game PCBs.
 
Sometimes I cut the traces to a transistor to test it on board and out of circuit. Not a great way to test them but it does work. Another way to test a transistor with a heat sink is to use "Technician in a can" or just plain old freeze spray. You just freeze the part/heat sink to see if there are any changes and it gives you a place to start from.
Good luck.
bill
 
A good VOM meter is all you really need (and a schematic would help) and measure voltages.

That being said you also do not need to remove it from the circuit (so to speak) - just desolder and couple of the legs are you are good. There really is no need to removie it from the board if you wish to test it this way. Again you really only need to use a VOM.

A tracker is ok to have, but in my 25+ years in the electonics field, I have only used one maybe a dozen times. Most troubleshooting can be done with a meter and on rare occasion a scope by measuring voltage levels (or signals). Logic probes are a quick method for digital signals, but a VOM could also be used.
 
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