I might have put the resistor in the wrong location . I removed R1020 and put it in R9’s location . No change to the voltages on Q2001 Q2012 I still only get 1 volt on the collectors
I think the issue with the amp is on the output card . I removed it powered the amp up and all voltages are normal on Q2001,2012,2010,Q2000
wondering if you might happen to know what might go bad on the output board to cause this ?
wondering if you might happen to know what might go bad on the output board to cause this ?
I don't know what could be wrong on the driver board but sometimes an IC will fail and draw too much current.
What value (marked and measured) is the resistor in location R9?
What value (marked and measured) is the resistor in location R9?
Ok well I’m gonna have to order some parts for this amp to rebuild the output board and get a 30 ohm resistor
I wouldn't do anything with the driver board until you replace R9.
Are you saying that R9 was never the correct value since we started this?
Are you saying that R9 was never the correct value since we started this?
R9 was the resistor in circuit when the amp played clean audio . I removed it to touch up some solder connections and put it back in the amp in R1020 location instead of R9 but that was the resistor that came in the amp . And something on the output board is defective and it blew one of the outputs
There are 2 of these ic’s on the board and also a LM13700 along with several lm833
I forgot to order the LM13700 .
is there anyway to test the LM31700 ?
Wondering what’s more likely to fail on these boards the LM31700 or the HC74’s?
As said before one of the ic’s on the board maybe be defective and dragging down the regulated voltages .
But not sure which ic do I just replace them all ?
I forgot to order the LM13700 .
is there anyway to test the LM31700 ?
Wondering what’s more likely to fail on these boards the LM31700 or the HC74’s?
As said before one of the ic’s on the board maybe be defective and dragging down the regulated voltages .
But not sure which ic do I just replace them all ?
I've never seen the LM13700 fail in this amp and was VERY rare to fail on other amps. I've see the 74HC74 fail but not many times.
Virtually every failed IC that I've found on these boards was found thermally. I'd freeze the ICs with canned air and power the amp up. If you see one that defrosts very quickly, it's likely defective.
Virtually every failed IC that I've found on these boards was found thermally. I'd freeze the ICs with canned air and power the amp up. If you see one that defrosts very quickly, it's likely defective.
With the output card out of circuit I get the correct readings on Q2000,2010,2001,2012. With it in circuit I do not get the correct readings .
With it out of circuit I tested a few opamps to see if I had the proper voltage on them and I don’t .
I used the amps main ground terminal as reference but the voltage on pin 4 is 3 volts and 29 volts on pin 8 .
Any ideas ?
With it out of circuit I tested a few opamps to see if I had the proper voltage on them and I don’t .
I used the amps main ground terminal as reference but the voltage on pin 4 is 3 volts and 29 volts on pin 8 .
Any ideas ?
Ok before I go any further with this amp troubleshooting I forgot to order the 30 ohm resistor . That’s fore in R9 . The local shop has a 33 ohm will that work ?
Ok I have the 33 ohm in R9.
Output board is in the amp .
For my readings on the regulators do I use main ground terminal ? Q2000,2001,2010,2012?
Output board is in the amp .
For my readings on the regulators do I use main ground terminal ? Q2000,2001,2010,2012?
Ok I’ll admit I messed up when I installed one of the new ic’s the 74hc I installed backwards . I took it back off the board . What’s the likeliness it’s defective now ?