Please help, I've wrecked my Beresford

[leo]

Sounds like a faulty component to me, either op-amp or dac chip

Does the op-amp get warm/hot ? its going to be harder without a scope, you may have to resort to changing parts until you come across the fault.

If one channel is ok this tells me the regulation is probably ok.
When the music on the faulty channel goes off, do you hear any hum or buzzing on that channel?

[James G]

Sounds like a faulty component to me, either op-amp or dac chip

Does the op-amp get warm/hot ? its going to be harder without a scope, you may have to resort to changing parts until you come across the fault.

If one channel is ok this tells me the regulation is probably ok.
When the music on the faulty channel goes off, do you hear any hum or buzzing on that channel?

Leo, Leo, Leo! Just on a hope and a prayer I took a trip and picked up an LME48720 (the only thing the shop had that said might work), cut the old one out and popped it in and now I'm back in business! Lucky!

I've only been listening for 20 minutes, but I can't say that the 48720 sounds that much better than the original. Not too bad though and at least I know what the problem was now.

Thanks everyone for the help with troubleshooting. Stan, I recommended the 7520 to a friend that's using a fubar in his setup. I'll be getting more of your products in the future I'm sure!

[leo]

Excellent stuff! Thats great news

[NRG]

Good to read you got it working! The LM4562 is worth looking at when you feel up to a bit more soldering. Works really well and is part of Stan's MoD21 part 2. Also you might want to junk the cermic bypass o/p caps, never found those to sound any good...

[StanleyB]

Just on a hope and a prayer I took a trip and picked up an LME48720 (the only thing the shop had that said might work), cut the old one out and popped it in and now I'm back in business! Lucky!

As I said, the 4558 might have done a Luke ( it went sky walking). Glad to know that was it, and that you are up and running again.

Stan

[ultraviolet]

Looking closely at your pic, are you sure EC4 and EC5 are in the right way round? The stripe appears to be on the side facing the op-amp whereas on Stans photo it's on the opposite side. Assuming your caps stripe is marked as negative not positive.

[leo]

He'd have to check, its hard to see the pcb marking in the pic

Are EC4/5 the ones at the bottom of the pic? I presume these are for the op-amps input? not having a dac to check I have to guess

[ultraviolet]

Yes, bottom of pic. They are the input caps for the op-amp I believe.

[NRG]

See: http://www.beresford.me/Downloads/Mod21.pdf

The o/p seems to have them the wrong way 'round

[leo]

See: http://www.beresford.me/Downloads/Mod21.pdf

The o/p seems to have them the wrong way 'round

Oh yes, can see it on there