Orion HCCA 2100 no rail voltage.

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Working on an Orion HCCA 2100. It is not producing rail voltage. Pin 12 of the 494 is at +10.38v DC. I'm not that familiar with the layout of this amp, looking for some help fixing it.



I just replaced all the electrolytic capacitors, PS FET's, output transistors, MPSA06's and MPSA57's. Amp had a couple of blown PS FET's but did power up prior to me replacing those components.
 
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I noted that with the circuits design of these amps. How the board is layed out is different between the models.

The 494 DC voltages:
1. +0.014
2. -0.002
3. -0.022
4. +4.87
5. +1.476
6. +3.390
7. -0.00
8. +10.71
9. +0.012
10.+0.022
11.+10.71
12.+10.71
13.+4.90
14.+4.90
15.-0.002
16.+0.013


Given that the circuits are basically identical...as with the HCCA 225 it looks to be that the voltage on pin 4 is way to high.
 
With remote disconnected the voltage on the RCA shields was -0.00v. I then reconnected the remote and checked it again and it was still at -0.00v. Not sure why I got the +12.11v reading earlier but I'm thinking one of the speaker leads may have been touching the power connection on the remote wire.
 
Yes, the electrolytic cap near pin 8 of the 494 is connected to pins 4 and 14. I pulled it and checked it and it was shorted. Oddly it enough it was brand new.

I replaced it and the voltage on pin 4 of the 494 dropped down to where it should be.

I then pulled the resistor between pin 4 and 7 of the 494 and the voltage on pin 4 held where it should be.

I then pulled the choke(resistor) I had on the power lead and powered the amp up under full power. It powered up briefly and shut down. Could see nothing that visibility blew.

Present voltage on the 494:
1. +0.001
2. +2.034
3. +2.024
4. +0.001
5. 0.00
6. 0.00
7. 0.00
8. +0.023
9. 0.00
10. 0.00
11.+0.024
12.+0.024
13. 0.00
14. 0.00
15.+2.034
16.+0.001
 
Yes, I have remote.

Not sure what I did but all the voltages on the 494 is back to what they where previously. The voltage on pin 4 is at +4.87v DC again. I noted it is now intermittently fluctuating. It seems to hold at +4.87v for a bit but then starts fluctuating and drops as low as +0.375v then back to holding at +4.87v.
 
Yes, I have checked the RCA shields multiple times to make sure they are still at 0v. I pretty sure the speaker lead was touching the remote power connection when I got the +12v reading.


A 220 Ohm resistor brought the voltage down to 0.25v pulsating on pin 4. Power light on amp is still not coming on. I am powering it through a choke. PS FET's are heating up on the left side. Didn't want to try to power up with full power as I'm sure it will over heat the PS FET's even with them clamped.


Rail voltage is not even see photo.
 

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