Seiko H357-500A stopped working after I got hot

[traindriver69]

Hi all

I have a seiko dual analog and digital watch from the 80s that I love but I was wearing it one hot day and it stopped working I thought it might be moisture and if I heat it up with a hair dryer it does start working then stops again.

I have took the module out I dont know if someone out there can see anything that might be causing it not too work any help would be much appreciated.

many thanks

[Tudor]

Hi. I see a couple areas of concern:

that dark green area at the top may be corroded enough to break the trace when the board expands. 

And the connections at the bottom are also quite tarnished. 

Then in the zoom of the image I see the entire center area has darker green traces, and I’m wondering if they are all corroded or if there is something over them intentionally?

But the first step is a careful and thorough cleaning!

[traindriver69]

Hi Tudor

Thanks for your quick reply I have q-tips and isopropyl I also have a Fibreglass pen but would this be to harsh to clean any areas.

many thanks

[Tudor]

Always start with the least aggressive (deionized water and a q-tip) and then proceed up the aggressive scale carefully. Perhaps a pink pencil eraser (not the gritty “ink eraser”) would help after the water. 

But you need to get your nose in there with the loupe and really check for breaks.  

And be careful! There boards were not intended to be repaired, and are very delicate. 

[watchweasol]

Hi  other than what Tudor has advised  i.e.  cleaning the contact areas carefully  check  it out for dry joints  as the symptoms you describe are indicative of that or contact problems.