[sdiy] "re-cap" when it's SMT?

Magnus Danielson magnus at rubidium.dyndns.org
Sun Sep 29 15:21:48 CEST 2013


On 09/29/2013 04:36 AM, Pete Hartman wrote:
> To follow up on this....
>
> I did audio probes, and found:
>
> Only the left channel has the problem.
> The D/A chip (IC19, UPD63200GS-E2) left channel out (pin 11) has no
> sign of hiss.
> IC175, a 10uF SMT electrolytic--appears to be for blocking DC--has a
> bit of corrosion on the far side, and there is hiss there.
>
> First guess is then replace IC175 (we'll see how well that works for
> me; I'm not much good with wire trap connectors and there are LOTS of
> cables all around this section of the board).
>
> I'm curious if any of the more experienced members have an opinion on that.
Are you sure that it's a cap problem?
I would look at cross-talk from digital lines. Caps can help mitigate
that, but you need to look at it from a signal integrity way rather than
just audio by itself.

That only one channel has the problem is a great hint.

Cheers,
Magnus



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