water damage

N_Cook

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Nov 12, 2016, 6:15:16 AM11/12/16

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I have to decide how much time to spend on this
Vocalist live3, DSP harmoniser, indoors but ended up directly underneath
a rainfall gully leak of the house roof.
Instead of opening up and hairdrying, owner just put on a room radiator
overnight before powering up, via external 9V ac wall wart.
I have to decide how much time to spend on this. If there is no
corrossion product, mainly white stuff like battery corrossion product
or "tide-mark", anywhere in the DSP area does that mean water did not
get there?
No front panel LEDs or sw responses, main 7805 v reg is ok and one SMD
LED on the pcb lit. No fuses/CPs found. I can find no schematic for this.
There was still water inside this kit when I got it. Obvious corrossion
product lightly brushed off easily, from around pins of stuff in the
internal ps area, would it be tin salts, tin carbonate or some such ?
Just some staining of the pins , no obvious failed copper tracks and
very little green corrossion product. I've not determined yet whether
multilayer pcb.

Jon Elson

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Nov 12, 2016, 2:43:12 PM11/12/16

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If it is all low voltage inside, then maybe a good cleaning of both sides of
the board with alcohol and a toothbrush might clean it up enough to work.

One problem with situations like this is that the PC board can be cleaned up
well, but the pushbuttons, pots and such may not be easy to clean. And,
they may continue to deteriorate even after you finish with it.

Jon

N_Cook

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Nov 12, 2016, 3:10:45 PM11/12/16

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There is 48V supply which may be active all the time , as far as the ps,
only switched in by user. Luckily the controls section of the upper
board and the DSP and memory section of the main pcb seem to be
unaffected. Unfortunately the owner only gets on with the options
available on this particular model, but he never obyained a spare ,
depite being such a major piece of kit for his act.

Gareth Magennis

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Nov 12, 2016, 3:20:38 PM11/12/16

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"N_Cook" wrote in message news:o06tj2$e68$1...@dont-email.me...

My policy on such matters is that the equipment can NEVER now be relied on.
It is damaged, and may fail as a result any time soon, despite any remedies
you are charging the customer for.

You cannot see under the IC's, who knows what has collected there to wreak
havoc later.

If this is used in a studio, then sudden failure is perhaps not game over.
In a live situation, well, you really don't want that at all.

Gareth.

N_Cook

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Nov 12, 2016, 4:27:32 PM11/12/16

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Valid point, a use for my 60 yearold reel of 0.08mm rigid-for-its
diameter tungsten wire , a short length "rodded" through under the SO23
pins and the 1 8pin SOIC, probably a dual powerfet device, hopefully the
only afected active devices.

Gareth Magennis

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Nov 12, 2016, 5:24:44 PM11/12/16

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"N_Cook" wrote in message news:o081f1$d9s$1...@dont-email.me...

Yep, so anything you do is basically going to be a Punt.
The customer has to be happy he is paying for "hope".

I would not be able to guarantee my work under these circumstances and would
have to charge accordingly, or not at all.

Cheers,

Gareth.

Tim Schwartz

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Nov 13, 2016, 6:44:48 AM11/13/16

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Having read the thread, I look on line and found several used ones for
sale, including a nice looking one in the original box for US$175.
That's considerably less than 3 hours labor here, so I'd suggest the
customer look for nice a used one.

Regards,
Tim