Rotel RA-931 problem

[njholland]

Hello wise people at DIYaudio,

I wondered if someone might be able to help?

I have searched the forum and cannot find anyone who has had the same problem with this amp before.

When I bought it, I knew that it did not work, but did not know the problem. After fitting a fuse in the plug I thought that at least the red LED on the front should light when switched on, but it did not. So I removed the cover to see if it was anything obvious, and discovered something I had not seen before. As well as having the ususal rotel output fuses (in line with the speaker outputs), there were an extra two fuses on the main board. They were 5A. So I replaced them (because they were blown) and when I turned on the amp again they blew straight away.
Has anyone had this problem before/can anyone suggest what it might be/how to fix it?

To listen to, I know good hifi. Take the cover off and I am useless! So please, simple terminology would be appreciated!

Thanks for any help in advance,

Nick.

 

[anatech]

Hi Nick,
Welcome To DiyAudio!

They were 5A. So I replaced them (because they were blown) and when I turned on the amp again they blew straight away.

Don't do that! You may make the damage far worse. If a fuse looks melted, or has a little poof mark you can try to replace it. If the fuse has silvered or blackened the glass, you should not change the fuse.

You need someone with electronics training and equipment to help you. A bad service job will only cost you money and time, possibly the unit.

-Chris

 

[lt cdr data]

only a few things needed...

replace output transistors

replace psu caps

and bridge rectifiers, 1 or more of those should cure it.

if not, blown tranny or somehting else on the board

 

[Makofoed-6sn7]

lt cdr data,

That might work, but i sloppy. If the output transistors are blown the fault might very likely to be in the driver stage.


Else, I agree with anatech, you need basic knowlegde and some equpitment.

Best regards,

Magnus