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P2 losing time. :/

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cte

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P2 losing time. :/

Post20 Jan 2015, 21:52

I have recently fallen in love with my P2 again lol. It was without a battery for about a year. Now it's running again I <3

Before the last batteries died, I am sure it was losing a few mins a day. At the moment, with fresh batteries, it's losing about 20 seconds a day.

I am guessing the problem will get worse in the future. Are there any options to fix it or is it a case of buying a new module?

Thank you all. :)
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bruce wegmann

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Re: P2 losing time. :/

Post20 Jan 2015, 22:00

This is probably near the upper limit for quartz crystal off-frequency operation (this applies to watches running fast, too). At some point, the circuit will become too imbalanced, and the oscillator will cease to function. But, you don't need a new module, just a new crystal (preferably an original one). It's a ten-dollar, five-minute fix (I've done scores of them).
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cte

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Re: P2 losing time. :/

Post20 Jan 2015, 22:14

Ok. Thank you for the reply. That sounds promising. :P

If I manage to get hold of a crystal, would I be able to do the fix myself (I have basic/average watch repair skills)?

Cheers
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bruce wegmann

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Re: P2 losing time. :/

Post21 Jan 2015, 00:19

You need a fine-point soldering pencil, .25mm rosin-core solder, and a reasonably steady hand. You MUST be grounded while handling the module outside the case, so, either use a grounding strap, or do the repair on a foggy or rainy day (static charges can't form under conditions of high humidity). Cut the wires from the old crystal about mid-way (don't disturb the original connection to the circuit board), and wires from the new crystal to a length that makes them just touch the wires from the board, and apply a tiny bead of solder to the junction to establish a connection. Done right, it's barely noticeable.
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cte

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Re: P2 losing time. :/

Post21 Jan 2015, 01:48

Wow, thank you for your guidance. I will give this a try if I get hold of a crystal. So it's worth doing the change now before it gets worse, or can I wait till it gets worse/fails?

After your last post I did a little search for info on the procedure. I only found one thread on another forum. It talks of cutting the crystal from its protective cover and then resealing it afterward. Also, there was mention of crystals not fitting properly (shape/size) and having different timings etc.. This is all new to me. I will research the topic further.

If anyone is reading this and has a new original crystal for sale, send me a pm. Thanks. 8-)
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Re: P2 losing time. :/

Post21 Jan 2015, 22:15

cte,

Could you post a picture of your module showing the quartz crystal from the view of the crystal leads, in other words the side that connects to the printed circuit board (substrate). I've only seen a few pictures of Pulsar modules, but from what I've seen it appears that Pulsar, like other watch manufactures of that era, used either a Motorla or a Reeves-Hoffman crystal. I have both types in my stock and the price is right, ie. FREE, all I ask of you is to pay the postage from the US to the UK.

FYI...any quartz crystal requires that it be "loaded" with the proper capacitive load, specified by the manufacture, to enable it to oscillate at the correct frequency. Normally there is a "variable" capacitor (trimmer) mounted on the substrate for the purpose of adjusting the desired frequency. Both Motorola and Reeves-Hoffman sold crystals that ranged in required load capacitance values from about 7-16 pico farads, 12 pico farads being the ideal. The trimmer capacitance usually ranged in value from about 5-35 pico farads so that most any quartz crystal in the range of 7-16 pico farads could be tuned to the exact center frequency of 32.768KHz for the best time keeping accuracy. To insure that you get the best time keeping accuracy you may have to adjust the trimmer capacitor to pull a new crystal onto the center frequecy of 32.768KHz. Without proper instrumentation it is hard to do. I've been out of the electronic watch business for about 40 years and have no idea what is available for setting the quartz crystal on frequecy. Back in the 70's many jewelers had the necessary equipment to do so. If you replace your crystal, you may have to look around to find someone who has the equipment that can adjust the frequency for you.
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bruce wegmann

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Re: P2 losing time. :/

Post22 Jan 2015, 00:58

All the P2 and P3 crystals I have seen are made by Motorola. The earliest ones, which are very large and fill the entire recess at the top of the module, are marked MTQ-32. Later versions are progressively smaller and carry MTQ-32A, 32B and so on. So far, I have found no better instruments for measuring quartz module accuracy than the Zantech models 1000 and 1100 Quartz Watch Monitors.
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Re: P2 losing time. :/

Post22 Jan 2015, 01:43

Wow, that is most kind and very generous of you Ole Joe! I will certainly take you up on that offer. :mega: I will take a picture tomorrow. Bruce mentioned about being grounded when handling the P2 module. It's fairly rainy and miserable here in the UK at the moment lol. Hopefully it should be safe to remove the module and take a picture of the led front side? :scratch:

The timing/tuning/trimming does sound a little difficult without the proper equipment. I was actually doing some searching for info on trimming earlier today. Can anyone link me to a thread or site that describes the process in any detail?

Once again, thank you Ole Joe. You have made my day with your generosity. :grin1: The Internet can be a joy (sometimes lol). I will get that picture for you tomorrow. Thanks again to you as well Bruce. I think the Zantech monitors are going to be out of my price range. There is an 800 model for about $500 on eBay at the moment. :roll: Not sure how I can work around that.
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Re: P2 losing time. :/

Post22 Jan 2015, 03:11

cte,

If you are able to take pictures of your module tomorrow, include both sides of the module. I'm not sure how the crystal is mounted in the P2, so if you include front and back that should cover it. If the crystal is made by Motorola, I've got a drawer full of MTQ32C's.

Joe
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bruce wegmann

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Re: P2 losing time. :/

Post22 Jan 2015, 03:54

I have seen MTQ-32C crystals in fully original P2 and P3 modules, so they should be a simple, drop-in replacement.
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cte

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Re: P2 losing time. :/

Post22 Jan 2015, 22:11

When I changed my clothes after work today, I heard and felt the crackle of static. Bruce's words rang in my head. So, I have ordered a grounding strap. I took the back off the watch, but didn't touch the module. Whether the static build up might still affect things doing this, I don't know.

So, just one picture for the moment. I will post the other side once the band arrives. :-D

Image
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bruce wegmann

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Re: P2 losing time. :/

Post23 Jan 2015, 02:08

Yes, that's an MTQ-32 crystal. It's always best to replace with an identical original part, but a B or C version will work fine. The fine-adjust trimmer is the gold cylinder directly below the crystal can. Turning the screw clockwise slows the watch down, counterclockwise speeds it up (about 1sec/week/turn, total range 10sec/week). The coarse trimmer has about 10 times that range, so if you're off 20 seconds/day, you won't be able to get zero error without replacing the crystal. Tiny frequency errors build up to significant timekeeping errors; most people don't give any thought to (or aren't aware of) the fact that there are more than 31 million seconds in a year, so a crystal that's just 1 Hz off gains or loses nearly 1000 seconds/year...about 3 seconds/day. To stay within the original specs, frequency has to be accurate to + or - .065Hz.
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Re: P2 losing time. :/

Post24 Jan 2015, 21:26

Thank you Bruce. :mrgreen:

I have been keeping a record of my watch over the past few days. I think it's actually 10 or 11 seconds out a day. I might try trimming before I change the qc. I suppose the coarse trimmer on the front is a screw and works in the same way as the fine trimmer?
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Re: P2 losing time. :/

Post24 Jan 2015, 23:39

Actually, the front (coarse) trimmer is a one-turn type. Depending on where it is set, turning it clockwise, for example, might make your watch go faster or slower; there's no way to be certain without either doing some experimentation, or using a quartz monitor (another reason these are so handy to have!). If you're real lucky, you might just be able to null out the error with the coarse trimmer, but I wouldn't count on it, and without a monitor, it could take a long time to do it. Regulating watches to close tolerances has always been something of a black art; at least, now, with the right tools, it's not as time consuming as it used to be.
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Re: P2 losing time. :/

Post03 Feb 2015, 19:51

I just wanted to say a special thank you to Ole Joe. :grin1: Two lovely Quartz crystals arrived in the post this morning. I'm most chuffed. This is such a valuable community. :dwf: Thank you Ole Joe. I will post how I get on with them (once I get the courage to do the procedure lol). :mrgreen:

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