Quartz movement strange problem

[HectorLooi]

This is a strange problem that I've encountered with the IC potting material of Seiko watches.

The 1st photo is a Seiko 1N00. The usual black blob of epoxy or whatever potting material has disintegrated into a sticky, tar like substance. If I were to wash it in plain water, it'll wash away completely, leaving no traces of the IC.

I first encountered this problem while repairing my father's Seiko AGS. It demonstrated intermittent periods of working and periods of shorting out. Seiko had replace the accumulator, generator and pcb many years before but never really resolved the problem.

I tried to repair it last year and found some corrosion of the pcb tracks and some clear, sticky liquid around it. I assumed it was battery electrolyte and soaked the pcb in distilled water. When I fished it out, I was shocked to find that the entire IC disappeared! 

I've been searching for a replacement pcb but to no avail.

Have anyone else seen an IC disintegrate?

[jdm]

1 hour ago, HectorLooi said:

The usual black blob of epoxy or whatever potting material has disintegrated into a sticky, tar like substance.

That's not strange at all. A lot of the materials we generally name as "plastic" degrade even just over a few years. Did the designers knew that they were not to last, or there were variations beteween batches, that's anybody guess.

[JohnR725]

28 minutes ago, jdm said:

That's not strange at all. A lot of the materials we generally name as "plastic" degrade even just over a few years. Did the designers knew that they were not to last, or there were variations beteween batches, that's anybody guess.

I was in a class once given by eta and I believe he call that engineered material as opposed plastic. But my memory may be a little fuzzy but I'm pretty sure that's what was called.

The problem is with plastic as noted above it can do all kinds of interesting things with time usually none of which will be good. Plus if any environmental things are there like somebody who insist on cleaning it with solvents are not supposed to. But even without that plastic does have a habit of disintegrating. I have an electric watch around here with green plastic holding the battery and a lot of the components has just disintegrated.

then there may be other things going on like for instance if this is a resin that was mixed what if it didn't get mixed properly?

So if you have a watch that has plastic components you really should stock up on those components and hope they don't fail also.

[watchweasol]

I have a watch the same as JohnR725 who's geen plastic frame is just about dust, I have had quartz clock movements with the wheels with no teeth at all just a disc, niot all plastics are the same for sure.

[jdm]

6 minutes ago, watchweasol said:

not all plastics are the same for sure.

For sure. In the family we have then-expensive items from the '60s like tape recorders, 8mm projector, picnic set... Time just made the plastic harder. Possibly brittle, but I won't try.