Discussion in 'Pioneer Audio' started by CavScout, Jul 2, 2018.
The reading is 1.76
Check D3. The small glass diode connected to pin 7. I feel as though it is shorted. Give me the reading across that diode!
OK, now check the other 3 diodes the same way. D1, D7 and D9
if that is d5 amp board ding ding
Well D5 is the STV-4H biasing diode. If it is reading .533, then it is bad. Are you sure about that? What about D9??
Please take a picture of this D5 you just mentioned!!
Is the D5 you just checked the one with the long white insulated leads??
Oops, I stand corrected ( I thought that 9 was a 5 on the schematic)
Correct info is
D5 is 1.215
d5 seems low compare to d6
may have used schottky string in those if d6 same
All the diodes in the left channel are good!
d6 is the other channel and good comparison .
I agree, he should compare the 2 STV-4H diodes. Other than that, maybe two traces on the back side of the board are touching through a solder joint.
just measure the known good one first .
But the fact is that even if the STV-4H was completely shorted, it would not cause the leakage across the emitter and collector of Q5. So the STV-4H is not the problem.
yes it was academic . but things like this might be the cause of the problem . no harm in checking .
I did check and putting a short across the STV-4H does not cause a reading between the emitter and collector of Q5. That junction should read open.
D6 is 1.211
d5 is not a concern then .
Check the foil side (back) of the Amp board for shorts between the foils. And check every resistor in the circuit. You can make comparisons on the right channel. Also check all the caps too.
How do I check for shorts between the foils with a multimeter?
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