Rotel RA311 Schematic Needed

[ahd100]

Hello,

I'm new to this forum and I'm looking for some help.

I have recently been given a Rotel RA311 amp that is displaying some problems but I don't know where to start as I don't have a schematic to tell me what's going on in there.

It's displaying an audio frequency hum when switched on in all possible modes which I suspect is related to a large sawtooth looking 1MHz component I found when I put a scope on the output.

Any suggestions?

If you can help me find a schematic that would be most helpful.

Thanks very much,

Andrew

 

[metalman]

I had to contact Rotel directly for the schematics for my RA971MkII integrated. They sold me a service manual containing the schematic and service instructions etc. for US$20.

 

[mogga]

did you end up getting the schematic?

 

[jaycee]

The 311 is a very old amp. To start with, you should do a complete replacement of all electrolytic capacitors. That in itself might well cure the problem, as oscillation is a sign of dried up decoupling capacitors.

 

[stainless]

Link to services manual.

Service manual, eprom result list | ElektroTanya | Service manuals and repair tips for electronics experts

 

[JohanH]

or

Rotel RA-311 solid state amplifier

Cheers,
Johan

 

[mogga]

Thanks a lot mate

 

[raytoms]

Many thanks for this link. I have had my RA-311 since new in 1974. It was retired when I built up my home theatre, but has since been re-instated for audio in another room. Amazingly it works a treat. Slight cap noise for a few seconds on power up, but after that it is perfectly silent and sounds great. The only problem after being in storage is that the Power-On LED doesn't light up. Hence the need for the schematic to check voltage requirements for a new LED.