After my internet died for few hours on Sunday I decided to get round to cleaning up a DW5600C module that I recently picked up at a flea market.
Quite a nice one, it is a DW5600C-1 - note the 20 BAR instead of the usual 200M WATER RESIST. I believe this is the JDM version, also it is the 691 module with the mirror back.
When I reset it the module year read '85.
As you can see some scratches, typical of what you would expect when you buy a used module on ebay. When i buy these I will always look for chips, cracks and bubbles - avoid these. Even deep scratches can be polished out, I almost feel happy to see some scratched up crystal knowing it can be easily polished out and will probably be cheaper!
First up. I used wet-and-dry sand paper 400 grit. Pretty coarse but it cut down to the base of the scratches in a few minutes.
Next I used 1000 grit for about 5 minutes. Checking to see if any deeper scratches were still present.
After, I used 7 micron diamond paste on the back of the sandpaper to remove small surface scratches. Circular motion and checking every few minutes.
After 5 minutes it was smooth and bright, under scrutiny there were some microscopic pits still, but so small it wasn't worth worrying about. If you were more fussy you could repeat the above process to remove those, but it was good enough for me.
The back wasn't too bad, some light scratches. Usually I wont polish the back too much as it can dull the lettering. The back is the hardest to get right. Too much and it looks bad.
So go easy here- usually the milled backs e.g. the 901 module backs, I leave alone.
I used a dremel and 7 micron diamond paste again, to polish the superficial scratches. I finished it off with rag type Dremel wheel which applies less pressure.
Depending on the angle and the light, it looks mirror again, though some deeper scratches remain under scrutiny.
Finished in under an hour and looking a million % better!
A really good score, this crystal is a good one with no bubbling - even on the alarm spring.
Thanks for checking it out. The cost of the materials to do the crystal is under $10, so I think anyone can do it too!