Amplifier AVR200 seems to have a problem

[Geoffroy]

Good evening to all,

I don't know much about amplification but can do a bit of soldering and basic measurements with a multimeter.

I have been given an Arcam AVR200 amplifier which works fine until it starts heating up a bit. At that point, the left channel simply becomes much lower volume than the right one which I interprete to be due to overheating and the amp might wait for the channel to cool down. But this is my interpretation and the user manual does not say much about anything really.

Trying to investigate a bit I noticed there is a fan at the back of the amp and I would hope this fan would kick in to create an air movement but it does not. Could it be this? Is there anything else I should be looking out for?

If it has to be dumped I will have a lot of joy keeping some of the pieces for other simple projects

Thx for your help.

Cheers

Geoff

[Iain McNeill]

Does anything get hot? Can you feel the heat thermals over any devices?

Sounds like the thermal compensation is shot. When it heats up the bias dies. Is the sound distorted on that channel or just quiet?

Try and get some schematics and a meter. Comparing the good channel to the bad will reveal what's up.

[Geoffroy]

Good morning Neil,

Thank you replying yesterday night!

Yes the amp gets hot to touch (but not burning) and the signal is just faint (sometimes too faint to hear) but not distorted it seems.

Where can I get schematics/documentations? I found website proposing to sell them but they are expensive and look dodgy really.........

[Geoffroy]

Up Up! Can anyone help with this?

Cheers

Geoffroy

[Iain McNeill]

Is it similar to this model:
B&K AVR-202i DIY repair possible? Relays buzzing (I think) - otherwise normal?

If so maybe ZepofLed could let you know where he got schematics. But if the manufacturer won't sell/give you them then the only other option I know is the pay-sites you mention. I've used them in the past with success but they are a bit pricy.

[Geoffroy]

Good evening Iain!

I found a site where you can register for 5 bucks and get the schematics so it was ok. I haven't spent time looking into details but I found the temperature sensor on the heatsink (They write 100 oC but do not say if this is the max temperature or is a minimum temperature for it to react), I have also found from where the fan should be run (its electrical supply). This is only on one board (I think there is a board for the front/stereo and another one for surround and the thermal control is on the main stereo board). That's about all I can say right now. Should I test the sensor etc.. ? I will look into this during the week. If you want more info, can we discuss this in PM? I'm thinking about the fact that I probably cannot post the schematics here, can I?

I hope this is a small issue and can be solved after a few days of work as I would bad trashing it as it seems of OK build quality compared to others really )

Thank you again for your advice so far.

Cheers

Geoffroy