Good day guys, having issues with this amplifier (green board) have all the necessary voltages in fact I’m having my rail to rail oscillation (highside and lowside drive signal) but I know reasons im not getting any audio on my output pin from my preamp board..I have audio on U101 output, not much around U103 none on U104 (in fact I’ve replaced all 4 IC’s for good measure). Is there something I’m missing, all resistors checked off good.
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Ok yes it’s a switch, checked it and it’s fine.
Yes I’ve downloaded the diagram.
Without the input preamp board, if I induced audio to the input pin on the mainboard with signal ground, shouldn’t the amp play?
Yes I’ve downloaded the diagram.
Without the input preamp board, if I induced audio to the input pin on the mainboard with signal ground, shouldn’t the amp play?
Do you have the regulated supply voltage on all of the op-amps?
Did you follow the signal through the preamp board? If so, where do you lose the signal?
Do you have rail-rail oscillation on the output FETs?
Did you follow the signal through the preamp board? If so, where do you lose the signal?
Do you have rail-rail oscillation on the output FETs?
Yes I have 12+/- on all IC’s rail and I have rail to rail oscillation...however I lost audio on resistor R128 but even when I jumper it, I get no amplification from mainboard and even applied audio directly to the audio out pin and the amp seems mute.
Hopefully PapaZBill will visit the forum and give more difinitive instructions but I'll try to help until then.
The LM13600 can not handle much signal so the level is reduced significantly.
When you tried to inject signal, did you have the other RCA channel plugged into the amp so that you had a signal ground?
When you tried to inject signal, did you see any signal on the input pin of the class D driver board?
When you lost signal on R128, did you see any signal any farther down the line on any other op-amps?
If you think the LM13600 could be defective, you could likely bypass it.
Are any pins in the connector for the external bass control shorted together?
When you drive signal into the amp, do you see any modulation on the output FETs?
The LM13600 can not handle much signal so the level is reduced significantly.
When you tried to inject signal, did you have the other RCA channel plugged into the amp so that you had a signal ground?
When you tried to inject signal, did you see any signal on the input pin of the class D driver board?
When you lost signal on R128, did you see any signal any farther down the line on any other op-amps?
If you think the LM13600 could be defective, you could likely bypass it.
Are any pins in the connector for the external bass control shorted together?
When you drive signal into the amp, do you see any modulation on the output FETs?
New information, when I jumper from R128 to output pin on preamp board I get signal from amp, not too loud as expected (lack drive) but amplified, as I said no signal beyond that resistor (resistor good). I’ve also change that 13600d chips before and all TL074 and the one TL072, no pins in the remote port is shorting.
C123 and C128- 10uf 16v are good suspects.
Does pin 16 of the 13600 have -11 volts dc. Black probe on negative spkr terminal
Does pin 16 of the 13600 have -11 volts dc. Black probe on negative spkr terminal
Good morning guys, I’m getting -10.9 on pin 16 of the 13600 ic, I’ve replaced the C123 and C128 caps still not producing output, I’ve traced subwoofer audio up to pin 1 of U104 (opamp voltages are present) no output..
If I jumper pin1 to the output pin of the preamp board it plays but not clearly.
If I jumper pin1 to the output pin of the preamp board it plays but not clearly.
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U104 drives the invert out and invert in ports for the Parallel Amp operation. It's possible JA04 or JA05 ports have failed. Check both jacks and traces on the the preamp board. It's possible moisture has gotten underneath the jacks, You will have to remove them the board to see what's going on.
Also check the pins on the modular plug that connects the RJ11 plug for the remote bass controller. I've seen the pins get pushed over shorting to an adjacent pin.
Also check the pins on the modular plug that connects the RJ11 plug for the remote bass controller. I've seen the pins get pushed over shorting to an adjacent pin.
Great news, those jacks really had me around in circles, that’s to the team on this one, there was corrosion (erosive) trace that brings audio to the port switch, was eroded terminating audio under the input port for the strapping, it was hard to check also as the underside of the board is tedious when mounted to check each time.
But after removing it as instructed, everything was clear there on. Thanks again for all the help for a successful repair guys.
But after removing it as instructed, everything was clear there on. Thanks again for all the help for a successful repair guys.