The dreaded ‘signal lights not working’

[JLE888]

Bought an MP-2 recently. Received it and everything works well on it. Unfortunately the seller didn't disclose that the unit had the dreaded 'input signal LED lights not working' issue.

I'm aware that the CE425 chip was a proprietary part and that a replacement is not available. But has anyone had any luck getting it to work again? I was thinking of removing the chip, spraying some contact cleaner on the socket and cleaning the legs of the chip and then re-seating it. But it's also in a very difficult spot to be able to try that.

Since the chip is seated on a little satellite board, could there be another part there that fails that causes these lights to not work?

What would cause a seated chip like this to just fail? Seems like this kind of part would be built to last a long time in a socket.

[rnolan]

Hey JLE888, well congratulations getting a MP-2, my favourite ADA preamp .  Gregg put quite a bit of time into this issue, as far as I know he never solved it.  Upside is you don't "need" the leds.  Apart from seeing there is signal, I never notice them.

Gregg managed to track down the manufacturer of the chip, but no luck getting a new one produced.  He also bought a couple of MP-2s that weren't working for spares, and no doubt to get a working CE425.  But IIRC he ended up fixing the broken MP-2s rather than scavenging their parts.

Why does a chip like that fail .  It' seems to be age related to some extent, as in this issue has only come up recently. I.e. Gregg was the first to post about it. But since then it's become a little more common, i.e. you have the issue. And I think MJMP has seen it from time to time, but it is rare.

I've not had the issue across 5 MP-2s so far (and fingers crossed I don't).

[MarshallJMP]

I have seen a few bad ones and if they fail they usually get hot too, if that happends it's best to get it out since it puts some strain the 15V power supply.