Pulsar Display Fault.

[bucko170]

I picked up a cheap Pulsar Classic that was described as being faulty due to excessive battery drain.
I have tested the watch and all functions work and it keeps good time however the 'Sat' display (DOW module) is faintly but permanently lit up, which must explain if not fully at least partly the reason for the excessive battery drain.
I also noticed that the temperature effects the brightness of the rogue display, outside on a cold day it was not visible to the naked eye, inside close to a warm radiator it was much brighter.
Are there any quick fixes? I thought that maybe contamination on the module could be causing a short and wondered if a 'wash' might improve matters?

[retroleds]

I'd recommend you not try the wash on any P4 or beyond. Beneath the batteries is a cover for a few dozen wirebonds, and it is not particularly well sealed - so if you make it wet, how do you then dry it? You could try the front of the module at the date display area(blowing out with air or rinsing with distilled water very carefully), but that is really a relatively hopeless dream - when the display is not powered it would take one heck of a dust/dirt/leakage short to power that one display section. The real problem is [probably] back in the wire-bonds or an actual chip/circuit issue.

The rinse works for a P2/P3 since all the exposed wirebonds are under that one big IC, which has sufficient space under it for it to dry back out. Of course, that is a weakness when it comes to battery leakage.

[bucko170]

Thanks for the advice Ed, a simple fix would of been good but never mind the batteries lasted over a month I will just have to remove them when the watch is left in the display case.

[retroleds]

Maybe when you change them, take a look at the module and give it a little blow out(not likely to change). IF it shows any traces of leakage on it, you could try a very light wash of the front, using something like a small brush dipped in water or clear vinegar(followed by water) to riinse under/around the displays only. Allowing to dry well before powering up, of course.

[bucko170]

Would you recommend using Isopropanol?

[retroleds]

Would you recommend using Isopropanol?

For a rinse, instead of water, it is fine. I know the idea or using vinegar or another mild acid is controversial to some, but battery leakage generally creates metal salts. Something either mildly acid or mildly basic can get them into solution, so they can be rinsed off. Isopropyl can dissolve oils, but has little to no effect on any of the corrosive residues. But it's speedy drying is a plus - so it can be use to rinse deposits loosened or dissolved otherwise.

Good luck with it - now THAT would be a nice module for Hanno to work on. But a lot of work on that, and very few of the movements available to strip the displays off of.

[azimuth_pl]

If nothing helps you might use vinegar first, rinse in distilled water and then let it soak in alcohol which will replace the water. Place it on a mild heater or your house modem for a day or two and the sealed cavities should get dry.

Vinegar is controversial to some... well I remember the "some" to be the first to question using vinegar when I mentioned this option a long while back. Time flies, people change, nice.

[SASM]

The SASM35 will be ready this week, so there´s a replacement available finally. Hanno

[Ade51]

The SASM35 will be ready this week, so there´s a replacement available finally. Hanno

That's good news Hanno - I have a couple that need repacements - what will the exchange price be?

[bucko170]

Well after pondering it for a few months I decided it was bath time for the module, vinegar, sodium bicarb to neutralize followed by a distilled water rinse. The module is now drying out, update in around a week!