Rega Brio (one channel dead)

[cosinus]

Hi everybody !
I'm new here and I need a hand.
I have an old rega brio integrated amp with one dead channel on the power amp. I don't know what happened to it, I just got it like that.
So I opened it. Besides the fuse, there are a few resistors that are badly burnt. The schematics show which ones.
My question is: how should I proceed to fix it ? I mean which method should I follow.
-Should I change everything in the faulty channel, including all transistors and just set idle current at the end ?
-Are there any other components that are most likely dead too ?
-Should I only change the burnt resistors ?
I have an oscilloscope, a digital multimeter. And I'll use my PC as a signal generator to feed the preamp.
And I'm willing to spend some time on it because I find it interesting. Otherwise I'd have it serviced but it's a lazy option.
I would really appreciate the help of one of you guys. I am far from having your skills, but I studied electronics at school and can use all the instruments I listed. If I need something more, please tell me.
Thanks in advance.

[cosinus]

Hi there !
I realise it was a complex question, so I went searching a lot more. Well, I found this:
http://sound.westhost.com/troubleshooting.htm
It looks really good, just what I wanted. You might know it already. I post it in case some of you don't.

But there are still a few questions for you guys:
-What's your opinion about this amplifier, looking at the diagram ?
-What are your ideas to improve it ?

Regards

[FrancoB]

What a coincidence! I have the same amp with one channel dead. When I opened it, one fuse was blown. And two resistors.

But I don't see the resistor number listed on your schematic. Is that the complete schematic?

Maybe you have another part of the schematic.

Your help is highly appreciated.

Frank

[jaycee]

It is likely that T1, T2, T5 and T6 will be blown. You should replace these. Also check the op-amp is working. You may as well replace all the transistors as there's so few of them. You might be better dropping a better op amp such as NE5532 in there instead of the TL072 too, but if all you want is to get it working, replace with a TL072.

[Tekko]

This is a DC coupled amp, most likely the output transistors went which fried the fuse and the paralell resistor, this means you need to changre about everything on this channel board, including the opamp. Look for burnt copper traces too.

[jaycee]

It's not exactly a very well designed amplifier. The driver transistors are only rated for 100mA, and well, the 2955/3055 is older than time. Theres also no resistance to isolate the 2955/3055's from the speaker line. Looks like a recipe for disaster when it goes wrong.

Don't bother getting it serviced if you can do it yourself. Luckily the low parts count means it's relatively cheap to replace all the parts in the channel. You can get all of the transistors from OnSemi as samples

[FrancoB]

Thanks a lot for your replies. Does any of you have the complete schematic with a parts list?

Best regards,

Franco

[Ipanema]

Hi,

Out of curiosity of how this simple circuit may sound I build it with the layout attached. Currently one channel is working and another is coming. The working channel sounds find but it have a fairly loud "waterfall" noise, not "motorboating" sound, which is noticeable when no music is playing. Pls help to check what is wrong with my layout that causes this.

FYI, I use wire jumper to connect the "unrouted" path, which is VEE, VEE and regulator (7815/7915) to opamp.

Pls advise.

Thanks.

[Ipanema]

Here's the layout. Sorry

[Ipanema]

With components