Pioneer SC-82 with dc err

[pedroafonso]

I got this radio but i can find the fault yet. on the speakers output with chassis gnd shows 1.9 volts.
everything looks ok. but is i remove this 15+ line that feed the voltage regulator CN4002 to the pre amplifiers then the protection mode wont kick in.
i mesure the dc protect line and indeed goes low from 4.5 volts then the radio shut off
I know is something to do with the 15 volts line but i can figure it out

 

[PETERDECO]

Welcome to the forum. If I understand you correctly, you are measuring DC voltage on the speaker output. This could be the reason the protection circuit is shutting the radio down. Check the audio output stages and post a schematic of this.

 

[pedroafonso]

Hi Peter Thanks for the replay
I have 1.8 volts when the radio comes on without the 15+ volts line. I think thats my problem but the service manual states that the dc detect will come low when the dc voltage on outputs is higher than 7 Volts dc. so im a little confused on how much DC would be normal on a speakers output

 

[pedroafonso]

 

[pedroafonso]

I uploaded the full service manual in this link
https://u.pcloud.link/publink/show?code=VZauBqXZHcCyo8MtbABPB1JBSb4bF8XIShMk