Stuck Reed Switches?

[abem]

Hi.

I just bought a replacement P3 module for a women's oval (source: pulsarlelds.com / LED_LAND, Peter) and I found that the module is perpetually stuck in time setting mode with the minutes continually advancing.

The watch remains in time setting / minute advancing mode even if the module is removed from the case, so there's no possibility of interaction with the button magnets. I'm guessing that the problem may be a stuck reed switch. Is that a correct diagnosis or could it be something else?

I took a look at the reed switches, but couldn't say with any certainty whether there was anything amiss. The top reed switch, which advances the minutes is partially obscurred by a resistor, which makes it particularly difficult to see.

If this is a reed switch problem, does anyone know of a way to "unstick" them? Is the only solution to replace the reed switch or is there a quicker and easier fix? I tried exposing the switches to a more powerful magnet, but it didn't have any effect upon the problem.

Thanks 1.0e6 for any suggestions!

-abe.

photo of module:
http://img42.imageshack.us/img42/4664/d ... 0x1200.jpg
photo of lower time setting reed switch:
http://img42.imageshack.us/img42/5228/d ... 0x1200.jpg

[bruce wegmann]

Looks like this module has had a LOT of "work" done on it, judging by the amount of that black goop everywhere [I guarantee you, it wasn't there when that module left Time Computer!]. Also, this looks like a Dress module, based on the height of the digits [so, it's definitely not a P3]. I have seen this problem before, and it's a 100-to-1 shot against it being the reeds. The fact that it doesn't respond to even a powerful external magnetic field leans me toward thinking this is probably a logic glitch [on the clock chip, itself], and is thus beyond any help this world can offer...I have a Ladies' module that advances the date, endlessly, even with the switches cut completely out of the circuit. This is another good example of a problem that Time Computer rarely saw, if ever, because the watches didn't develop them until they were much older than the mere five years Time Computer was in business. So, we collectors, a third of a century down the road, are now seeing failure modes the factory never did...and the bad news is, it will only get worse, as the years pass...every day, there are a few less working Pulsars than the day before. What we see here is a heroic, but failed, attempt to keep a dying patient breathing...

[rewolf]

I agree with Bruce, but anyway I'd still try to remove the switch, resp. first disconnect one end, you can always resolder it - and you have nothing to lose, even if there's only a 1.0e-2 probability for success.
Magnetic fields of any orientation always close (this type of) reed switch, and the stronger the field the higher the contact force. A very strong field can even permanantly close the contact (residual magnetism).

[abem]

I do think it is a P3 module, with a few modifications. I compared it with the module from another working P3. I didn't feel up to taking apart my beloved Dress pulsar for comparison. Maybe some other time when I'm feeling confident or have a lapse of good judgement...

Here is a photo comparison with a working P3 module (problem module on the left, working one on the right):
http://img23.imageshack.us/img23/1196/p ... pariso.jpg

The most obvious difference is that the crystal is different. I'd guess that it's a non-factory replacement crystal since the shape of the plastic carrier is different than the shape of the crystal housing, but that's just a guess. I'd guess that the black goo is there for electrical insulation purposes, but again, I'm guessing.

They sure are fickle creatures. Do you think we would we love them as much if they weren't?

-abe.

p.s. on the plus side, Peter has offered to fix or replace it free of charge, so one way or another, we'll get her up and running again!

[retroleds]

Problem module has an oscillator chip installed. Notorious for fast running, high battery consumption.

[charger105]

They look like P4 modules to me.
Rgds.

[bruce wegmann]

Nope, definitely not P4...this is a Dress module. Note the right-hand side of the module...no Auto-Command switch [all P4s had that feature]. Digits too tall for Ladies' models, also.

[retroleds]

I'm with Bruce on this one completely - Dress modules strapped to P4 chassis. Men's circuits not Ladies, due to size of charecters and fact that leftmost character is a "1" only character(split) - the ladies modules almost exclusively used a full 7 segment character and only utilized the two, left, vertical segments needed for a "1".

[abem]

Hi. I'm certainly not an expert (relatively speaking), but here is some evidence that at least the display is from a P3, if not the entire module.

The P3 modules that I've seen have little 8 spoked circles inside of the digits whereas the Dress models do not have any traces or other markings inside of the digits. The displays may vary a bit since Pulsar had a number of subcontractors for displays, but thus far the P3 modules that I've examined have all had the Litronix displays with the little spoked circles as shown below.

P3 display - note circles with spokes inside of digits and also "Litronix" signature:
http://img41.imageshack.us/img41/9957/d ... 0x1200.jpg

Dress model display - plain digits with no signature:
http://img107.imageshack.us/img107/914/ ... x1200r.jpg

Also, note that on the P3, the metal trace going down the right side of the module has a bevel on the top AND the bottom whereas on the P4, it's bevelled only at the top as shown below:
http://crazywatches.w.interia.pl/photo/ ... ds_p4.html

Just out of curiosity - does anyone have any idea what the little spoked circles are for? Cooling, perhaps? I was surprised to see them - At first, they almost reminded of tiny analog watch faces!

-abe.

[bruce wegmann]

Fundamental difference between P3 and P4 displays...P3: each digit is constructed of seven independant LED segments, each a seperate chip, containing 5 individual LEDs. P4: each digit is a single chip, containing 7 integrated LED segments, each composed of 12 or 13 LEDs, in groups of 3 or 4 [here, the individual LEDs are so close together that the eye cannot resolve the spaces between them, giving rise to the impression of a smooth, uninterrupted line. The P3 dots are far apart enough that the seperations are visible. So, basically, dots=P1, P2, P3. Lines=P4, Dress. Modified dot-type displays exist for the Calculator and Ladies models, both extremely rare.