On 2020/11/17 6:59 a.m., Peter W. wrote:
A friend of mine brought over his ADT pushbutton panel the other day, reporting it "not working". It is fed from the back either by a 4.5V power-supply (wall-wart) or 3 x AA batteries in a pocket between the body and the wall-mount. Two things had happened:
a) The little SMT power-jack had pulled away on two of the four tabs. That was a quick fix.
b) In some previous time, one of the batteries had leaked and there was a large build-up of green salts concealed under the batteries.

He had installed new batteries, but the salts had bridged connections, causing them to short. I used an electric drafting eraser and dental picks to get all the corrosion out and soldered over the traces. It works.
NOTE: Those salts are deliquescent - meaning that they attract water out of the air - so no surprise on the migration.

Peter Wieck
Melrose Park, PA


White vinegar 50:50 with water is a good neutralizer for the alkaline
salts. Foams up then washes off...got that tip back in the late 80s or
early 90s from Duracell (or Eveready) mail in tech support. Have long
since lost the letter...

CLR also works, it too is a mild base.

John :-#)#

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