Did you let the meter probes slip? If so, do you know which pins you shorted together?
Does the amp produce rail voltage (check at the outputs)? At least one leg of each output transistor should have rail voltage (approximately ±80v).
Does the amp produce rail voltage (check at the outputs)? At least one leg of each output transistor should have rail voltage (approximately ±80v).
this amp never had that high since i got it. but it was in the high 50's as it was before this happened.
it hapeened while testing pin 6. there is no visible damage to anything and im not familiar with how this amp operates.
Yes it does it was in the high 50's i believe. It was also that high while it was working. If i recal pin 6 after i shorted what ever I did had 14.3V with remote on and it would climb down by a tenth of a volt slowly after the remote was removed. Also the amp does not pop on power down anymore. I wanna say it has something to do with the preamp section but again its just a guess.
You never said what happened. Did you let the probe slip and short between pins on the driver board or did the amp short out on something on the bench?
If you let the probe slip, you probably destroyed the opto-coupler (which may have been defective anyway).
If you let the probe slip, you probably destroyed the opto-coupler (which may have been defective anyway).
oh sorry perry yes the probe hit something on the dirver board or what ever it is called the one that it mounted off the main board. it did not see hwat was shorted though just heard a tick and then it didnt work after that had happened
Confirm that you have the following:
Positive and negative rail voltage on the outputs.
Positive and negative regulated voltage (12-15v) on the op-amps in the pre-amp section (pins 4 and 8).
0v DC across the speaker terminals.
~1v DC across pins 3 and 4 of IC 304 after the mute delay (after the red light goes off).
If you have all of the above, the voltage across pins 5 and 6 of the opto-coupler (IC 304) should be ~0.2v after the mute delay. if it's not, the opto-coupler is likely damaged. The following part should be a good substitute.
Mouser: 630-ACPL-827-060E
Positive and negative rail voltage on the outputs.
Positive and negative regulated voltage (12-15v) on the op-amps in the pre-amp section (pins 4 and 8).
0v DC across the speaker terminals.
~1v DC across pins 3 and 4 of IC 304 after the mute delay (after the red light goes off).
If you have all of the above, the voltage across pins 5 and 6 of the opto-coupler (IC 304) should be ~0.2v after the mute delay. if it's not, the opto-coupler is likely damaged. The following part should be a good substitute.
Mouser: 630-ACPL-827-060E
were do you want me cheacking the rails?
I have 0 DC across speaker terminals
IC304 had 1.1 V across 3 and 4 and 47.5V across 5 and 6
are the op-amps the 8 JRC 072d pieces by all the adjustments? if so there all at 30.3V
I have 0 DC across speaker terminals
IC304 had 1.1 V across 3 and 4 and 47.5V across 5 and 6
are the op-amps the 8 JRC 072d pieces by all the adjustments? if so there all at 30.3V
You can check the rail voltage on the outputs. You should find approximately ±50v on various legs of the outputs.
Yes. The op-amps are the TL072s.
With your meter probe, short pins 5 and 6 of IC 304 together. Does the amp produce audio when 5 and 6 are shorted?
Yes. The op-amps are the TL072s.
With your meter probe, short pins 5 and 6 of IC 304 together. Does the amp produce audio when 5 and 6 are shorted?
Yes. It may have been part of the original problem or there may be a problem in the circuit driving it that caused the popping.
Does the voltage on pin 5 of IC302 ramp up slowly after you apply remote voltage and drop instantly when you remove remote voltage?
Does the voltage on pin 5 of IC302 ramp up slowly after you apply remote voltage and drop instantly when you remove remote voltage?
If the power and protect LEDs are switching from red to green after the mute delay AND if the audio switched off without a pop when you removed the short from pins 5 and 6, the opto-coupler is likely the only problem.
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