R25, 36, 27 are good. As noted D1 lights. I've got a Hakko fr300; so I can get them out. Got a mega 328. It'll probably test Q9, but it would not test Q6. I think I have an old dmm that could test transistors. I pull them out and see what happens, otherwise I'll get them all tested by Monday.
I have been there and done that.
It has been a few years ago I exploded a capacitor or two with tube amplifier 400VDC voltages.
Now I fire things up inside 16 gauge electrical j boxes. And or use the bench power supplies that Santa brought to my lab. The kind of power supply you can set a limited current and limited voltage. Then turn the juice up in limited increments avoiding wrong way capacitors from venting in your face.
Good Luck DT
It has been a few years ago I exploded a capacitor or two with tube amplifier 400VDC voltages.
Now I fire things up inside 16 gauge electrical j boxes. And or use the bench power supplies that Santa brought to my lab. The kind of power supply you can set a limited current and limited voltage. Then turn the juice up in limited increments avoiding wrong way capacitors from venting in your face.
Good Luck DT
I don’t know that tester specifically. But I would assume if a transistor doesn’t read as the expected type of transistor then it is blown. Sometimes I see blown transistors as 2 diodes instead of NPN, for example. Then I know it’s time to swap in a known good new one. I test the new one in the tester to be sure.
The super inexpensive (el cheapo) Mega328 component tester, which sells for about USD 12 without acrylic case on eBay, achieves its amazingly low price by making some compromises. As a result, it gives the right answer most of the time --- but not always. Many diyAudio members have discovered that, for example, Mega328 doesn't recognize a Toshiba 2SK170BL as an Nchannel JFET. But it does recognize a Fairchild J113. Oof.
I mentioned that the Mega 328 would not test Q6, but did test the Q7 that I removed;. Nothing I have around gives me a reliable test on Q9; I've ordered a few on Amazon that will be here tomorrow.
Ironically, I have a Digilent AD2 system. They released a Transistor Tester module several months ago. I bought one, put aside, and promptly forgot about it. I found it this morning, but cannot - so far - make it work. I'm sure I'll have it figured out in a week or so (when I won't need it).
Did R23/24 burn up AGAIN when you ran your last test last week? How many times have they burned up? And remind me what was wrong with Q6?
It looks like you know that the actives and passive parts are known good for this next round. And if you're going to fire it all up with known good parts I hope we see 20V on the PSU rails when you test that board solo.
Looking forward to your results!
It looks like you know that the actives and passive parts are known good for this next round. And if you're going to fire it all up with known good parts I hope we see 20V on the PSU rails when you test that board solo.
Looking forward to your results!