ETA 555.415 Circuit Board Cleaning

[RickTock]

Hi folks,

I'm working on a quartz ETA 555.415 that has probably been sitting unused for a couple of decades. Putting in a fresh battery causes the seconds hand to jitter a bit, but that's it. Hand setting stem still adjusts the date and time properly.

I decided to disassemble and clean the movement. Upon disassembly, I discovered liquid under the circuit board and some showing top-side around the quartz crystal oscillator. The battery compartment is dry.

Any idea what the liquid is? What is the best way to clean the circuit board.

Cheers!

[HectorLooi]

That is most likely to be battery juice, sodium or potassium hydroxide. 

I would rinse it in distilled water and brush it gentle with an artist's brush.

The jittering is not likely to be a pcb fault. It's probably to electrolyte  crystals in the movement train or corrosion caused by the electrolyte.

If you have a quartz watch tester, use the "line release" function to see if the hands can move freely. If not, a complete disassembly and clean is needed.

Also, the quartz watch tester can test if the pcb is producing a pulse.

Good luck.

[RickTock]

I was too busy to do any watch work today, but did notice that all the liquid evaporated over night. So now I'm guessing it was just water. The watch is completely disassembled and will go through proper clean/rinse cycles next.