Schematic for RCA RS2640

[shortcircuit]

Does anyone happen to have a schematic for this all in one stereo ?? Was cutting out once it warmed up , now it just buzzes no audio .

[Leo_Gnardo]

it just buzzes no audio .

Classic symptom of a failed main filter capacitor. I don't have a schematic. It shouldn't take too much head-scratching to find that cap and clip another similarly rated one in its place, see if your prize starts working again.

[shortcircuit]

Classic symptom of a failed main filter capacitor. I don't have a schematic. It shouldn't take too much head-scratching to find that cap and clip another similarly rated one in its place, see if your prize starts working again.

Thank You , actually got one of them to spill it's guts , all my replacements are to low voltage ,will be on my next order.

[shortcircuit]

Thank You , actually got one of them to spill it's guts , all my replacements are to low voltage ,will be on my next order.

Replaced both main filter caps plus one other, still just a buzz , you can hear the volume click up on the speakers, no audio output from any of the functions cd,tape etc or headphones. any suggestions ?? , start tracing

[The Dude]

Schematic is here:

https://elektrotanya.com/rca_rs2640.pdf/download.html

I would start by checking all power supply voltages.

[shortcircuit]

Schematic is here:

https://elektrotanya.com/rca_rs2640.pdf/download.html

I would start by checking all power supply voltages.

Thank You very much , you are The Dude , appreciate your excellent support

[shortcircuit]

Schematic is here:

https://elektrotanya.com/rca_rs2640.pdf/download.html

I would start by checking all power supply voltages.

D821= -31.47vdc
D509-D512 =8.35vdc
D505-D508 = 40.7vdc / -40.7vdc
above and below 10% , bad transformer ??

[shortcircuit]

Schematic is here:

https://elektrotanya.com/rca_rs2640.pdf/download.html

I would start by checking all power supply voltages.

rca-2-.jpeg
D821= -31.47vdc
D509-D512 =8.35vdc
D505-D508 = 40.7vdc / -40.7vdc
above and below 10% , bad transformer ?? not blowing fuses, I'm thinking I need to get voltages to IC501 the audio amp I don't have any

[The Dude]

My apologies, I haven't gone through your measurements. A bit slammed at work today. If you don't have voltage to your audio amp, look at that rectifier circuit consisting of D505-D508. That's where supply comes from. Check the fuses F503 & F504. If one or both is open, it's likely one of your audio amps shorted. Check the audio amps supply pins to ground and to each other and make sure there are no shorts. If there are, you will just blow the fuses again. If those fuses are good, measure the AC voltage at N801A and make sure there is AC supplied to the rectifier circuit.

[shortcircuit]

My apologies, I haven't gone through your measurements. A bit slammed at work today. If you don't have voltage to your audio amp, look at that rectifier circuit consisting of D505-D508. That's where supply comes from. Check the fuses F503 & F504. If one or both is open, it's likely one of your audio amps shorted. Check the audio amps supply pins to ground and to each other and make sure there are no shorts. If there are, you will just blow the fuses again. If those fuses are good, measure the AC voltage at N801A and make sure there is AC supplied to the rectifier circuit.

fuses are good, have 29.25vac at N801a , have 40.7vdc & -40.7vdc from D505-D508 , thanks for the reply , no apologies necessary ,appreciate all you do and have done
?? even if the amp was shorted wouldn't I have voltage to the pins 2&15 that should have 29.8v??

[The Dude]

So you have DC out of the rectifier, but not at the IC suppy pins? If that's the case, you must have connection problems- cold solder, burnt trace, etc. Check continuity from your rectifier supply to the IC supply pins and verify that the connection is good.

[g1]

The +/- 40V should be showing up at pins 7 and 8 of the amp IC's, they are not there? It should be a straight run from the rectifiers, no burnt traces?
You said 8.35V at D510? What are voltages at pins 1&3 of IC503?

[J M Fahey]

As a side note, I wouldn´t worry about finding +/-41V rails instead of +/-31.

TDA7293 are happy with both, 2 possibilities to explain the difference:
1) a plain old typo. Happens in the best families. The writer might have wanted to say "31V **AC** ... which will give you about 41V DC rails.
2) factory variation.
Maybe original version used 31V rails, then they improved it and offered the higher ones, which increase power out.

In any case, well within Power Amp ICs, so ...... no big deal.

[shortcircuit]

The +/- 40V should be showing up at pins 7 and 8 of the amp IC's, they are not there? It should be a straight run from the rectifiers, no burnt traces?
You said 8.35V at D510? What are voltages at pins 1&3 of IC503?

Thank You g1
Have +/-40vdc at pins 7 & 8 , I owe The Dude an apology on that , voltage at IC503 pin1 18.65vdc , pin3 11.76vdc ,
IC501 pins 1,3,4,5,9,10,11,12 =0vdc pin 2=-1vdc , pin6 =13.35vdc (and starts dropping if you stay on it) 7&8 = 41/-41 vdc , pin13= 41vdc,pin 14= -1vdc , pin 15= -41vdc
my mistake was was going off the voltage chart on pg7-1,which is no where close to any of these

[shortcircuit]

As a side note, I wouldn´t worry about finding +/-41V rails instead of +/-31.

TDA7293 are happy with both, 2 possibilities to explain the difference:
1) a plain old typo. Happens in the best families. The writer might have wanted to say "31V **AC** ... which will give you about 41V DC rails.
2) factory variation.
Maybe original version used 31V rails, then they improved it and offered the higher ones, which increase power out.

In any case, well within Power Amp ICs, so ...... no big deal.

Thanks for the intel , appreciate it