Pulsar reed switch color coding scheme

[coconutman351]

Anyone know the significance of the color coding of the Pulsar reed switches? I have a P2 date II that I'm working on that has a green one for the date switch and red marked one on the time switch. What I'm looking for is data indicating what these colors actually represent for these switches. i.e. red = sensitive? green = weak? ..etc. Are there also other colors out there as well?

If there is an existing discussion topic already let me know where to look for it.

appreciate it!

[bruce wegmann]

Time Computer did color-code all demand reed switches (the setting reeds are activated by an external magnet strong enough that minor differences in the swiches are unimportant, so sorting them by sensitivity was unnecessary...at least, I have never seen a color-coded setting reed). I have seen only red and green (and many that are unmarked...which may, in fact constitute a third category). My experience has been that green reeds are more sensitive than red, with the unmarked ones falling somewhere in the middle. This system was maintained through all P2, P3, P4, and Ladies' Pulsars, until the Touch-Command models were introduced in 1976 (at which point, modules and cases finally became truly interchangeable). The Calculator models use an entirely different method of function activation. When replacing a damaged reed, it is always best to try a similarly-coded switch first (it is also best to note the actual position and rotational orientation of the original switch, and install the replacement as similarly as possible). Even then, you are still not guaranteed to get perfect button response, but I can think of no better place to start. Reed and quartz replacement were probably the only actual repairs that the factory ever did on these modules; anything more serious would probably have merited simply replacing the entire unit.

[coconutman351]

Great information thanks Bruce.

Just this week I worked on a couple of Pulsars to adjust the sensitivity of the reed switches and buttons. In some posts they suggest moving the reed switches towards or away from the magnetic buttons. I found it very difficult and worried that added pressure from the module would crack these delicate glass switches if they were moved from their slot in the module. For magnetic buttons too strong I glued a small piece of thin steel metal on the switch plate to defuse the magnetic field. You can adjust the sensitivity by the size of the steel and location of it on the switch plate. It works perfectly and reduces the hassles of replacing buttons. For buttons that were not strong enough, I exercised the reed switches a few times with a strong magnet and I find it tends to work. Now I have a perfectly working P2 date II and P3 GF watch in my collection.

For the P2 upon installing a battery the seconds would continue to count up and the date button would not work. Indicated a magnet a bit too strong for the time function and a weak one for the date.

For the P3 the symptoms were the date function stays on when the button is pressed. If you tapped the watch it would turn off.

[bruce wegmann]

Buttons with overly-strong magnets are the easiest problem to fix. The factory accomplished this with what was called a "high-mu shunt" (here, "mu" is pronounced "mew"). Installation of one of these is actually shown in the Pulsar Jeweler's Manual, page 23. Mu-metal is the industry name for a high-nickel iron alloy that has the property of conducting (and diverting), magnetic field lines; in effect, a type of magnetic shielding. I have never encountered a too-strong button I could not correct with one of these (and, of course, they are invaluable when matching a replacement module to a case...I have encountered a number of Pulsars with these shunts installed on one or both button covers...almost certainly a factory repair). I have some short strips of original factory shunt material, if anyone out there is suffering a watch that lights up at the slightest touch of the button; I consider button response ideal when the function is activated with the button about three-quarters to seven-eighths of the way through its' range of travel.

[coconutman351]

Bruce, how did you deal with button magnets that were too weak? Did you have your set of unique tricks or was it primarily replacing the buttons. I want to avoid it at all costs as I've read horror stories in this forum about the challenges of putting the buttons back on.

[retroleds]

In some posts they suggest moving the reed switches towards or away from the magnetic buttons. I found it very difficult and worried that added pressure from the module would crack these delicate glass switches if they were moved from their slot in the module. For magnetic buttons too strong I glued a small piece of thin steel metal on the switch plate to defuse the magnetic field. You can adjust the sensitivity by the size of the steel and location of it on the switch plate. It works perfectly and reduces the hassles of replacing buttons..

For the P2 upon installing a battery the seconds would continue to count up and the date button would not work. Indicated a magnet a bit too strong for the time function and a weak one for the date.

For the P3 the symptoms were the date function stays on when the button is pressed. If you tapped the watch it would turn off.

Moving the reed - good luck. As you have noted, you really can't move them out of their slot much toward the button and you have issues of the module not laying in the case correctly, leads shorting on case. Your P3 may* need a shunt on the date side. Note the shunt gets installed 180 from the one on the time side. The pictures in the manual are from the back...don't get it screwed up whilst turning.

Your magnetic shunts are not really addressing the issue correctly - you are resorting to totally blocking the magnetism, until the button is pushed in enough to "bleed" through the steel. You are going to be very frustrated long term, as you unnecessarily drain the button magnet with the continuous layer of steel. The factory shunts had a hole in them, which lines up with the off-center position of the magnets in the button. If you look carefully at the Pulsar jeweler's manual we have online here(top of Home page, under "Digital Workbench") you will find the shunt installation directions. Applying this logic correctly will work like 99% of the time on overly sensitive buttons. .0015" chrome steel shim stock works a charm - available from any tool & die supply.

On your P3 with date not setting from same magnet as time - FLIP the magnet 180, putting the same flat face against the hour/date slot. This will often work as the magnets are polarized from short end to short end - and one direction the setting magnet is working WITH the button magnet, the other direction it is working AGAINST the button magnet.

You cannot "exercise" a reed switch - you have successfully magnetized it temporarily and will have more trouble in the future, I assure you.

The color-coding: I personally think that is [slightly] wishful thinking. I believe that the red-dotted reeds are indicating "replacement" and nothing more.

*Final thoughts on the P3 with the goofy button - fill the button externally with rubbing alcohol, then pump up and down with a clean facial tissue over it - some yuck come out? Do that a few times, then blow out and lubricate with a plastic/rubber safe lubricant(CRC's 2-26 electrical lubricat is fantastic...Home Depot). Work up and down and then do your best to pull the button outward(may have to go side to side...don't use a metal tool, clean, dry fingers or soft wood/plastic). That will help reseat the rubber gasket on the button flange and help assure the button has maximum travel outward. To pull it away from the temperamental reed.

Sorry I'm not joining in more these days, I promised myself some break from watches this summer, and that includes the forum to some extent.

[coconutman351]

Thank you for the tips RetroLED, really good information here. I will try the shunts and reference the service manual on how to properly install it. I'll also clean the buttons. I think it's a great idea clean out the buttons occasionally as dust and dirt can easily accumulate.

As I said before, this forum rocks, not like some other ones that practically have no activity at all.

many thanks again.

[bruce wegmann]

Was going to post earlier but got distracted...anyway...
To clean out button cavities, I use pure acetone, forced in under pressure with a solvent applicator needle. It has much lower viscosity than alcohol (and most rubbing alcohol, to reduce flammability, contains 15% or so of water, which, unless the case is heated, tends to remain after the alcohol evaporates), and has a greatly enhanced ability to dissolve grease and oil, which is what is holding the dirt in there. The button seals are urethane, which is unaffected by this solvent (at least, I have not had it cause any problems). If you let the liquid coming out of the button fall on a white sheet of paper, you will be able to see every trace of the material being dislodged. Working the button constantly during the flushing does aid the process. You might expect to use 20 or 30 cc of solvent to do a thorough job. I'm not sure the factory intended the buttons to be lubricated in any way; over time, most lubricants seem to turn into adhesives, and re-attract fine dust and dirt. Conventional ultrasonic cleaning works adequately as long as the contamination is not very severe. A combination of both techniques may be required on watches that were worn a lot in particularly dusty environments.

[retroleds]

I'm not sure the factory intended the buttons to be lubricated in any way; over time, most lubricants seem to turn into adhesives, and re-attract fine dust and dirt. Conventional ultrasonic cleaning works adequately as long as the contamination is not very severe. A combination of both techniques may be required on watches that were worn a lot in particularly dusty environments.

Bruce, I agree that most lubricants leave too much residue and would gather crude. But the CRC 2-26 lubricant(which I know I suggest ad nauseum) isn't like that, it drys to such a thin layer, almost like a fine liquid silicone, that it doesn't even really hold all but maybe the finest dusts. "Leaves a thin, molecular, non-hardening film that increases equipment life by combating the return of moisture and corrosion. Displaces moisture. Safe for use on all plastics." Sounds impressive on paper, I'd date it if I was single.

Acetone is a good choice too, but most people find it a little too nasty to be smelling and working with much. Alcohol smells a bit like booze, which makes it fairly acceptable, if you embibe ....not sure how much of a drying issue there is if blown out sufficiently. Generally I am removing glass on a Pulsar I am cleaning(so I can rebrush), so it is going in the oven. And this button cleaning should be done before that - no point in cooking crude onto a watch(ditto on the bracelet crude). Acetone? the smell of death by nailpolish [remover].



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[bruce wegmann]

I'll leave the lubricating part to the discretion of the owner(s). And, whatever solvent you're using, you should do this outdoors. As organic solvents go, acetone is one of the most benign, but still not sutable for inhalation, and rubbing alcohol, while perhaps a bit more pleasant-smelling, is isopropyl (not ethyl, the kind you can drink), so inhaling those vapors probably isn't a good idea, either. I do this sort of stuff out on the patio, where the open air makes exposure minimal.

[coconutman351]

On the subject of case magnetic buttons and the issue of them loosing their magnetic strength, would the exposure to heat while removing the watch crystal cause degradation to the magnet's performance (the procedure of putting the entire case in an oven)? Or is this negligible? I don't know there was ever a case where the magnetic button performance was adversely affected by such a procedure. I read an article that if the magnet is heated to its curing temperature it could loose most, if not all, of its magnetic strength.

[bruce wegmann]

The critical temperature at which a magnetic material loses its' magnetic properties is called the "curie point". The hot-air gun is hundreds of degrees C. below that, so there is no danger of thermal demagnetization from this heat source.

[coconutman351]

How about if you use the oven method. A heat gun might be better to direct the heat to its intended target, the glue holding the crystal in place. Perhaps even at 400 degrees it is not enough heat to disrupt the alignment of the atomic domains and dipoles on these buttons.

[bruce wegmann]

Not even close. The Time Computer magnets are sintered AlNiCo 5 (an industry standard at the time), and hold their magnetic orientation up to 835 degrees C. (1538degF.), hot enough to bring your watch case to a bright cherry-red. Exposure to a mere 400 degrees F. can't even begin to depolarize these magnets (but, exposure to very intense magnetic fields can...that is how they are originally polarized at the factory, using a powerful electromagnet called a "gap magnet"). Close proximity to the new, super-strong eare-earth magnets can also weaken or repolarize them (or, if you get the field orientation right, re-strengthen a weak one).