MOSFET and zener diode checking on VVR?

[rogb]

Just doing some work on a VVR I have and wondered if any members had some simple checks for mosfets and 12v zener diodes. I had a look around the net but I like to here the views on here

[selloutrr]

This is as good as any if all you have is a DMM it's not 100% but it's a basic good/bad test. I'm not sure if the test will work if the fet is wired into the circuit.

http://www.utm.edu/staff/leeb/mostest.htm

[rogb]

That will do nicely! Thanks! Any good tests for zeners, I have a diode mode on my DMM, assuming they are tested differently from regular diodes?

I tested 2, 1 shows a similar result to a normal diode and 1 seems not to read at all...?

[selloutrr]

interesting article. you have to apply voltage while you test zener with a DMM

http://www.elexp.com/t_test.htm

[rogb]

Thanks, I found a similar article, this one is clearer, though

After adapting my fixed bias VVR to cathode bias specs...

I did the mosfet test and it seemed fine, and the zener wasn't opencircuit so I temp wired in the VVR and it was fine!

I can turn the B+ right down on the VVR while keeping the OD level up,

overloading the pre amp can be avoided by tweaking down the pre-amp volume.
Result is more feedback at lower volume - great!

Now I am fitting the VVR board in the chassis sidewall as per ODS FET board.

I have fitted 1N4007s to divide the power supply but I will swap them out for the faster UF4007 (when I find the buggers )

Thanks again for taking the time to help out, I had a VVR on my old 5 watter SE scaling the whole amp, power tube only seems ideal on the mini HRM