This amp came in with a shorted toroid, vented C59 and vented C17.
I replaced all defective parts and upon power up the cap C59 immediately vents. C17 cap did not. It is installed correctly, I double checked.
I removed C59 again and checked the pads for voltage.
+ 13.57 on pos pad
- 0.957 on neg pad
The original cap for C59 was 100uf 25v. I installed a 100uf 50v and powered the amp and it did not vent.
I checked the pads with the cap installed and am getting +46vdc on the postive lead and the same reading on the negative lead as before.
This cap is tied directly to Q13 LM317 positive regulator. The in voltage on pin 3 of the regulator is obviously also 46vdc.
D6 and D8 also have the 46vdc on the cathode end.
I am confused as to where this 46vdc is coming from. It does explain why the 25v cap was venting, but not 100% sure how its getting there.
I replaced all defective parts and upon power up the cap C59 immediately vents. C17 cap did not. It is installed correctly, I double checked.
I removed C59 again and checked the pads for voltage.
+ 13.57 on pos pad
- 0.957 on neg pad
The original cap for C59 was 100uf 25v. I installed a 100uf 50v and powered the amp and it did not vent.
I checked the pads with the cap installed and am getting +46vdc on the postive lead and the same reading on the negative lead as before.
This cap is tied directly to Q13 LM317 positive regulator. The in voltage on pin 3 of the regulator is obviously also 46vdc.
D6 and D8 also have the 46vdc on the cathode end.
I am confused as to where this 46vdc is coming from. It does explain why the 25v cap was venting, but not 100% sure how its getting there.
I tested for audio before reading your post and it shorted U10. I replaced U10 and it shorted again powering up. So U10 is removed and I also removed Q108, Q109, Q101, and Q102. I was going to replace them anyway.
Will this change the out come of the requested reading?
If not the reading across C59 is +22.09vdc
Will this change the out come of the requested reading?
If not the reading across C59 is +22.09vdc
Are 4 of the outputs still in the circuit?
Troubleshooting may be simpler if you disconnect the output from the power supply by desoldering the red/black wires on the rectifier end.
You have to measure directly across the capacitor. It's floating with the rails.
Troubleshooting may be simpler if you disconnect the output from the power supply by desoldering the red/black wires on the rectifier end.
You have to measure directly across the capacitor. It's floating with the rails.
That supply is floating with the output. Desoldering the rectifier ends of the red/black wires and connecting a load across the speaker terminals will make reading voltage and viewing signals simpler.
Without the rail voltage, do you have clean DC on the positive terminal of that capacitor?
Without the rail voltage, do you have clean DC on the positive terminal of that capacitor?