Pulsar P4 module 402 problem, some questions

[elceedee]

Hey guys
I received a P4 with a clean 402 module, showing the following behavior:
After a battery placement the watch shows two zero's or ones on its right both digits (minutes) and stays that way (leds keep 'on')
Pushing buttons does not make it change its behavior (three quick pushes etc), the two '0' or '1' digits stay on
My quarts timer doesn't read the quartz crystal (happens more often due to casing etc), but I assume that if that was broken the module wouldn't show any sign of life (?)
A broken chip?
How does one remove the module from the P4? For now it looks pretty stiff in place, im not going to force anything. The original gasket sits tight in place and has 'hardened'; removing it will break it. Its there a movement retaining ring under the gasket?

Im totally new to this module, all help and advice is welcome. Thanks

[bucko170]

So if the quartz does not read on the timer doesn't that indicate that it is defunct?

[elceedee]

Hi
Yes, my assumption is that its probably defect.
I have nil experience with this module and was hoping for some advice, e.g. a reset (how, if possible), maybe a defective reed switch, a loose contact of some sort, defective quartz crystal etc
As I haven't been able to remove the module yet, I haven't been able to look at its front side
Any advice on the case build? Is there a movement retaining ring under the gasket? Or is the movement just set in place very tight and do I need to use a more brutal force
Etc.

[bucko170]

From what I remember it's just a snug fit - once the two retaining screws have been removed that is.

Some good photo's on Piotr's site which might be of help http://www.crazywatches.pl/led,1

[SASM]

Was the watch working before you changed the batteries?

If yes, you probably have a short between one battery and the case. Use #386 batteries and no #357. Usually the short is caused by a loose battery terminal spring on the case back. Open the watch, and hold the case back from the back side to the batteries. What happens? Problem solved? - Reattach battery terminal. Not solved? Remove module. Maybe a reed Switch touches the case...

If the watch wasn´t working it´s probably the chip and there´s not much you can do.

Hanno.

[bruce wegmann]

ALL P4s use 357s, not 386s; it's what they were designed to use. It's a;most impossible that the batteries are the problem here. Most likely...bad quartz or damaged chip. Pairs of digits staying lit without the oscillator working is actually a very bad sign; it indicates a "forbidden" logic state that suggests damage to the chip (most probably by static electricity).

[SASM]

I agree that it is most likely the chip but I do not share the opinion that the oscillator might be the reason (definately not) or that this problem cannot be caused by a component or the battery that has unwanted contact to the case.

[elceedee]

Thanks a lot for a great help guys. I removed the movement and had a look. No loose contacts. Switches seem OK. The movement had not suffered from leakage. As its solid state and its contact look OK I conclude its a defective chip. Shame ..

[Ole Joe]

Before buying a new module, original or replacement type, spend the money, less than $1.00, to purchase a new quartz crystal. Classic sign of the oscillator not working are random digits showing, like yours, upon battery installation. Digits displayed upon battery installation with no other functions working is NOT normally a sign of static damage or a "very bad sign" that the chip is damaged but most likely due to the internal logic not being reset to the design default state when power is applied. Every function of the watch depends upon the quartz oscillator being operational including the internal logic reset circuitry, button functions etc. The quartz crystals of the '70 vintage were very susceptible to schock, i.e., like dropping the watch on to the floor while putting it on or removing it from ones wrist. Static damage to the metal gate type of CMOS chips used in these watches is rare. They had pretty "robust" input protection circuitry built in. I have personnely discharged in excess of 4000 volts directly into the input of this type of metal gate CMOS chips without damage. If you try a new quartz crystal and the module comes alive, and you also want the original Motorola quartz crystals which were used in this era watch module, let me know as I have some in my stock.

[elceedee]

Hello Joe,
That is a hope-giving message. My quartz timer isn't reading the oscillator, as mentioned before. My experience, usually, with LCD watches is that the oscillator is a part of the circuit: the watch wont work. But there are more types of damage to the oscillator..
Nothing to loose; I will install a new oscillator and have a look. I will keep you guys updated.
What frequency does the P4 402 oscillator runs on?

[Ole Joe]

Quartz crystal frequency of 32.768 KHz = 32768 Hz. If possible, try and purchase a quartz crystal that is specified for a "load" capacitance of about
10 - 12 picofarads.

[elceedee]

Hey all ,
I promised to bring an update after the surgery. I replaced the oscillator, unfortunately this had no effect on the movements behavior. It was worth the try
Better luck next time!
Thanks!