Best practice - diode mode or powered on voltage testing?

[caphair]

I'm curious if using diode mode for troubleshooting is faster/easier/reliable compared to voltage testing to locate areas of fault?

By diode mode I mean, device off, red probe on ground and black probe at inputs/outputs and if meter shows 0v then indicates a short

Recently I was troubleshooting a Plasma tv and I used diode mode to pinpoint shorted IGBTs on the X main board. Normally I'd power on and check for missing voltages but didn't want to deal with the risk

Curious on other's input and reasons for how they troubleshoot

[momaka]

Re: Best practice - diode mode or powered on voltage testing?

If testing PSU outputs, I prefer to just measure the voltage first. Reason being is that you get instant information if the PSU is working or not.

If measuring the output of a PSU in diode mode, sometimes low-resistance discharge/dummy load resistors (like 47 Ohms or less) can fool you into thinking there is a short-circuit (especially if your meter has diode mode combined with continuity, like many cheap meters do). If not that, sometimes large caps can take a long time to charge in reverse when you place your probes on the PSUs outputs. This means your meter may show a "short-circuit" for several seconds before the caps charge. If you don't wait for that, then you may erroneously conclude that something is shorted when it isn't.

[CapLeaker]

Re: Best practice - diode mode or powered on voltage testing?

For me, that would depend on what I am repairing and what the fault is.

[petehall347]

Re: Best practice - diode mode or powered on voltage testing?

huntron tracker would be a better way .. one of those things i still need to build .