Ampeg SVT-6 Pro No Output

[ca7922303]

R34(.39/.66 diode test) out of circuit. Will replace those three(3) R4/33/34.

[ca7922303]

D20(0/0 diode test). Will replace.

[ca7922303]

Relay pin1 should be zero ohms to pin5 when not energized. When energized pin1 should connect to pin4. So at least one of yours is definitely bad.
HF115F-A 024-1ZS1 will be good sub. (ebay)

Trying to find 1n748 3.3v zener diodes online and finding 748a(3.9v/.5w). Will this work for replacement? Thanks.

[Delta362]

I think you misread the 6 for an 8.

1N746 is the 3.3V Zener.

[ca7922303]

I think you misread the 6 for an 8.

1N746 is the 3.3V Zener.

Appreciate that! Thanks.

[ca7922303]

Relay pin1 should be zero ohms to pin5 when not energized. When energized pin1 should connect to pin4. So at least one of yours is definitely bad.
HF115F-A 024-1ZS1 will be good sub. (ebay)

Seems like a lot of zener diodes are bad associated with the mosfets. I've ordered enough to replace probably all of them. Best to go all new you think?

[g1]

Yes. And in post #181 I think you meant D's instead of R's.
When you have them replaced (or while removed) re-check those resistors that were reading different than their counterparts in post #130, also R16 and R17 from post #179.

[ca7922303]

Yes. And in post #181 I think you meant D's instead of R's.
When you have them replaced (or while removed) re-check those resistors that were reading different than their counterparts in post #130, also R16 and R17 from post #179.

Will do. Diodes(digikey)should be in next week, relays from eBay coming from China might show up 3rd or 4th week of august

[ca7922303]

Yes. And in post #181 I think you meant D's instead of R's.
When you have them replaced (or while removed) re-check those resistors that were reading different than their counterparts in post #130, also R16 and R17 from post #179.

Got relays in today earlier than expected from China. These read (OL) between pin 1 &.5 and (0.00 ohms) between pins 1 & 4.

[g1]

Got relays in today earlier than expected from China. These read (OL) between pin 1 &.5 and (0.00 ohms) between pins 1 & 4.

That sounds like the opposite of what they should be. This is out of circuit?

[g1]

Actually what you report matches the relay datasheet. So there may be an error on the schematic as to pins 4 and 5. Or the original relay datasheet has an error.
With the relay removed, see which pad on the board is connected to ground, pin4 or pin5?

[ca7922303]

That sounds like the opposite of what they should be. This is out of circuit?

Yes, measured out of circuit.

[ca7922303]

Actually what you report matches the relay datasheet. So there may be an error on the schematic as to pins 4 and 5. Or the original relay datasheet has an error.
With the relay removed, see which pad on the board is connected to ground, pin4 or pin5?

#4 pads are connected to ground.

[g1]

#4 pads are connected to ground.

Well that is a major relief. It means the error is on the schematic and the parts you got are correct. ( nevetslab might want to add error to his notes).
So the relay that seemed bad was good, (post #175). Not sure if the other original one read the same or not? Maybe they were both good.

[ca7922303]

Well that is a major relief. It means the error is on the schematic and the parts you got are correct. ( nevetslab might want to add error to his notes).
So the relay that seemed bad was good, (post #175). Not sure if the other original one read the same or not? Maybe they were both good.

One reads (0.00) @ pin #4 and one (0.00) @ pin #5 so I'll just replace em both with new and hold on to one as good I guess. I'm still waiting on some 1n4743 diodes on order before I start testing again.