Module DOA - Cleaning Tips?

[s_elias]

Hi,

I've had several ebay buys of watches with dead modules - suprise suprise.

I've read on the forum, members recommend the acid bath (vinegar, baking soda, distiller water wash) as a last resort.

Has anyone had limited success with this? If so, what worked best?

a) How long did you soak the module in vinegar or did you skip the acid bath and soak the module in the "fizz" right away?

Thanks

[bucko170]

Hi,

I've had several ebay buys of watches with dead modules - suprise suprise.

I've read on the forum, members recommend the acid bath (vinegar, baking soda, distiller water wash) as a last resort.

Has anyone had limited success with this? If so, what worked best?

a) How long did you soak the module in vinegar or did you skip the acid bath and soak the module in the "fizz" right away?

Thanks

Following the tips on the forum I have tried this on several occasions using vinegar first followed by baking soda and distilled water bathing in each solution for around about eight minutes and then leaving to dry in a warm place for three to four days.

The success rate has been pretty poor, I have maybe got one or two working again but I never expected a high success rate as I only attempt this as a last resort on modules that are easily replaceable so what gets to have a bath is mostly those that are already dead. I have found that the ones that do seem to respond the best are the Frontier modules - don't know why this would be.

[laptop]

Hi Elias,
I used a few times as last resort and it worked a few times. But be careful, I put for only 40 secs on the warm vinegar bath, because I could see the vinegar acting pretty fast on the deposits of oxidation (and i got scared )
Clean them carefully but surely with distilled water, make sure to be clean without any residue and NO humidity before you try new batteries.
After I gently blow with pressured air (from a air can), I use a blow hair drier on low temperature and you have to be very patient not to heat the module too much.
The modules that never responded on my case was the bulova modules (the ones that have the red plastic carrier). And the ones that better responded was the Pulsars (don't look at me like this, , it worked)
As Bucko said, just try it as last resort.
Let us know how it go.
Take care.
I'm just a curious guy that is crazy about old watches, don't take my experience as advise, but only as comments of my own inconsequent try outs. "Don't try this at home"

[retroleds]

Nooooooooooooooooooooo. Realistically dropping the module in could get all sorts of moisture underneath ICs, displays and on-board circuits that are covered with rubber or such(think Frontier). And soak into ceramic circuit boards*. I think the "Drop the whole thing in" idea came from Pulsar's suggestion that jewelers could, as a desperate last resort, plunge a P2-P3 module into clean water, swish gently and then gently blow dry. Which might possibly clear some detritus from the exposed wire-bonds on the underside of the IC chip, which can be blown out fairly thoroughly due to the design. And everything else being well sealed. That technique would be terrible for a P4, since their circuit is fairly unsealed on the [hidden] back side, just having a poorly fitting plastic cap over a ton of wirebonds. You might get water in but how would you get it out?

My suggestion:
Small amount of it on a cotton swab, not even wet enough to squeeze a drop out of. Dab, dab, rinse,rinse in same semi-dry fashion. I personally have been using and suggesting one of the liquid products they sell for removing rust and corrosion from your bathroom fixtures, such as CLR in the USA. They use gluconic and lactic acids which work much faster with less manual scrubbing and give the dissolved metal salts less time to soak into ceramic substrates. YMMV On thicker corrosion vinegar seems to just "stall" - I think the relatively high water content is the problem.

*I used to try removing traces with acid for my Bulova Big Block mods but I would get shorts and failures - seems the dissolved metal was soaking into the ceramic board and still conducting some current. Sandblasting them off solved THAT problem.