Pulsar Timing chip

[GravityZ]

Hi,

i have read the following thread

http://www.dwf.nu/viewtopic.php?t=1304

in which you can see that the crystal has been replaced by a timingchip
i was told that phill from ledwatch.net made these chips(or at least he knew were to get them

is there anybody who can give me some info about this chip?

thanks

[fronzelneekburm]

Video killed the radio star... uhhh i mean oscillator chips killed the quartz. :D

Yeah, these 2x2 mm oscillator chips can be quite handy.


Sitime is probably the most popular manufacturer for the small ones.

http://www.sitime.com/products/sit1.php

[bruce wegmann]

These are not 2mm square, but 4 x 6.5. They fit rather neatly in the pocket that originally held the [Motorola] quartz crystal, but they have several drawbacks [beyond the obvious esthetic one]. First, the module is no longer factory-spec. Second, they draw about twice as much current as the quartz crystal, so there is a significant reduction in battery life. Wiring them into the existing circuit requires bypassing the trimmers, so it is no longer possible to adjust the timekeeping accuracy [and for some reason I cannot determine, they run, amazingly consistantly, about one second a day slow; I have no data on the rate that might change with time]. Bottom line is, it's still better than a dead watch, though I think that, in the interests of honestly and accuracy, the presence of one of these should be made known to any potential buyer.

[rewolf]

Sitime is probably the most popular manufacturer for the small ones.

http://www.sitime.com/products/sit1.php

Those look nice, but I can only find 1MHz or higher. Is there a 32kHz version?

[leddwatch]

All Pulsar P3 and P2's will fail in the oscillator stage one day, they are a time bomb ticking! There is a component in the watch which deals with heat changes, it was made to make small amounts of timing change to the oscillator circuit, for example if you leave your watch on a cold window sill or have it on your arm it is designed to not lose or gain time.

The component they used is suffering from bi-metal decay, due to a chemical reaction, they will all need this modification one day and are failing at a very high rate. The modification, if you use the right oscillator, only reduces the battery life slightly, surely its got to be an advantage to have a working pulsar with slightly reduced battery life and accuracy than a dead one?If you want to know more about this I can post pictures.

Cheers

Phil

[collector]

Hi Phil,

I find your post about the metal decay very interesting. Can you tell us any more as to why etc - Pictures would also be greatly appreciated!!

[gjlelec]

Phil, does the chemical reaction still take place if the batteries are removed from the watch. Do you personally remove the batteries on the watches you are not likely to wear or leave them functioning. I recall reading threads regarding the quartz crystals becoming less accurate with use but still don't know if i should remove the cells or not

[GravityZ]

bimetal part would suggest that there is a moving part inside the watch because that is what bimetal is used for
personally i think they probably used some kind of metal which is more sensitive to temperatures.
like al metal the resistance changes when the temperature changes
temperature higher=resistance lower
temperature lower=resistance higher

nowadays they use NTC's and PTC resistors which do the job.
maybee they also existed in the 70's but was the quality not as good as they are today.

did they put this INSIDE the mainchip!!!!!!

Phil, does the chemical reaction still take place if the batteries are removed from the watch. Do you personally remove the batteries on the watches you are not likely to wear or leave them functioning. I recall reading threads regarding the quartz crystals becoming less accurate with use but still don't know if i should remove the cells or not

[retroleds]

All Pulsar P3 and P2's will fail in the oscillator stage one day, they are a time bomb ticking! There is a component in the watch which deals with heat changes, it was made to make small amounts of timing change to the oscillator circuit, for example if you leave your watch on a cold window sill or have it on your arm it is designed to not lose or gain time.

The component they used is suffering from bi-metal decay, due to a chemical reaction, they will all need this modification one day and are failing at a very high rate. The modification, if you use the right oscillator, only reduces the battery life slightly, surely its got to be an advantage to have a working pulsar with slightly reduced battery life and accuracy than a dead one?If you want to know more about this I can post pictures.
Cheers
Phil

Huh, first I have ever heard of a temperature compensation unit in a Pulsar. :? But to the point - what does that have to do with the oscillator? The temperature compensator(if there was one, it certainly isn't inside of the oscillator...I've pulled plenty open just for my edification). And why not just replace the crystal with one of modern composition, as I have done on about 400 modules of various makes just in the last year, and 40-50 Pulsars? Those oscillators have not replaced quartz oscillators - virtually every electronic watch made today relies on a simple quartz oscillator.

I also question the poster who mentioned 6.5 pf ....not many that used that one.

[Higgie]

Ed, the crystal is not faulty, but the electronics inside the IC.
This is a common flaw in Pulsar modules
Try this:

A Pulsar module that's only showing one digit, replace the crystal with a new one.
Still the same error?
Now do this, ( it sounds a bit stupid ) put a sine-wave directly on the the PCB where normally the cristal is soldered. An audio-signal ( music from your MP3-player for example ) will let the watch run again.
Ofcourse way too slow and irratic, but now you know you need an oscillator pack.

This is my Module-oscillator tester, just stick the wires on the cristal contacts, is it running? Then replace the crystal with a oscillator-pack.
If not, R.I.P.

[retroleds]

HIggie:
So you're saying the oscillator is going to push the "beat" thru the flawed IC when the crystal can't? And that double current drain makes me wonder how the iscillator might be taxing the IC. The rough trimmer on the front of the module - bypassed too?

If the fine trimmer is being bypassed, then I take it you're not checking that it isn't part of the issue? Lots of those have been seriously manhandled.

But hey, if it works, might be worth it on the ones that are goners otherwise...you've got me curious, now I'll have to get some. 8)

No comments, so I take it everyone has discovered the ImageShack Toolbar....

[Higgie]

Yep, it's so powerful it even goes thru the damaged oscillator circuitry.
And powerconsumption is approx. 3 uA so the effect is only about 3 months less running time ( not half ).

It's your choice, a dead module or a watch thats suddenly worth twice you paid for it.

Just wondering, if i sell one should i mention it if my module looks like this ??

[leddwatch]

Quote by Ed:
Huh, first I have ever heard of a temperature compensation unit in a Pulsar. :? But to the point - what does that have to do with the oscillator? The temperature compensator(if there was one, it certainly isn't inside of the oscillator...I've pulled plenty open just for my edification).

Haha, theres something you are all missing, I assure you that there is a component that you dont know about !! let me get my camera out, first of all as a little tease question..... why is that if you get the single digit problem on a P2 or P3, you put the watch on a radiator and it springs to life, everyone has seen that havent they? When it cools down it stops working again.......

[retroleds]

Hey, if there's something to be learned here, I'm open to it. I would be the first to admit I came to Pulsar's late in my digital addiction.
8) CAMERA!!.....ACTION!!
Imageshack?

[bruce wegmann]

Higgie, seriously, if you bought a watch that was represented as "all original" or "mint", and you opened it up and saw that bucket of worms, what would you do? I'd have the guy's head on a pike, and make it my life's mission to make sure they didn't pull this on anyone else. I think it's OK to sell anything you want, as long as the buyer is properly informed about what they're buying [I am not implying any misconduct on your part; I am speaking here in general terms]. Even now, if you're looking for a working, reliable watch, the phrase "as is" should be a major red flag, especially if you're new to the hobby, or don't have a penny to waste. That's why pictures are so important on eBay; I've saved thousands by paying attention to the details in the photos, and if the pics are bad, I don't even worry about making a bid, unless what I can certainly see is worth more than what I'm bidding. I'm inclined to agree that the vast majority of Pulsars are going to give up the ghost in the next 10 or 20 years [especially any that have suffered a leaking battery, and almost any bodge of a repair will be considered justified to keep them working], and eventually, fully working, original modules are going to be worth stupid amounts of money, but we are many years away from that. In the meantime, I have no fundamental objection to this sort of repair, as long as it is made known to the buyer [and neatness DOES count here; I would not return a module to a customer looking quite that rough, working or not].

[retroleds]

Higgie, the repair is just fine(IMO), other than maybe you'd want to cover the wires with some black "plasti-Dip"(liquid rubber) so it won't get snagged or shorted and look a little more "factory". I still want to see the pictures you were suggesting regarding the mystery part.

It's hell being the site administrator...I don't get to put anyone's head on a pike anymore!

[leddwatch]

Ok fellas, my apologies for playing the guessing game, it took me years to figure it out, behold R73 and R75, two variable resistors, their impedance changing with heat..... now you know why the radiator trick works and why the extra oscillator manages to get through the first stage of the IC, its because theres nothing wrong with the IC, the fault is in these temperature variable components, you dont have to put the super oscillator in, you can start the oscillator running by altering the bias on pin 5 and 8 of the IC.

It took me years to figure it out, the fault occurs because these fancy resistors are breaking down over time....can you see them now??

The truth is out!

[bruce wegmann]

Ordinarily, you'd see these components ONLY if you had X-ray vision, as they lie directly UNDER the clock-chip package. In the process of dismantling numerous [seriously damaged] modules for parts, I had seen these serpentine traces and wondered exactly what function they performed. I thought they might be capacitors, but the trace pattern was not right for that [I am now guessing that all similar traces on the board are also resistors of various values]. The question I'm sure everyone is asking now is, how does one go about changing the bias on pins 5 and 8? There's certainly not much room to work with in this area of the circuit board, as the coarse trimmer cap is within a fraction of millimeter of the chip package. Have you sucessfully done such a repair, and if so, how?

[retroleds]

Wow, awesome piece of work guys. 8) Looks like you are bypassing the vari-resistor section completely. Seems like that was a real waste of effort to build in, as the large, water filled mass of the human body keeps the internals of a watch at around 86 F. over a fairly wide range of external temperatures. I have at least a dozen Pulsar modules with "issues", this will make for some great experimenting.

[leddwatch]

Hi Bruce, you have to take out the rough trimmer to work in that area, whilst messing about there I always solder a 30pf capacitor in place of the trimmer, this gives you lots more space to work.

If anyone wants some fun, take an old scrap module, take off the chip and put your multimeter across the big resistor under the chip, now breathe hot air on it and you will see the impedance increase and likewise decrease when you blow cool air onto it. The amounts are quite dramatic, there is quite a large swing either way, this gives you a good idea of the resistor values to play with.

This is how the P2 and P3 was given accuracy in hot or cold conditions, by these two current limiting resistors, but when either one breaks down then the oscillator faults comes along. When you do the radiator trick the heat causes a large enough swing and expansion that the watch starts working again. Im giving everyone the benefit of my years of research here!!

Here is part of the schematic diagram of the P3, showing the resistors, R73 and R75 going onto pins 5 and 8 of the chip. 63 is the quartz crystal and 67 the rough and fine trimmers.

Have fun!!

[embelton]

Ive said it before and I´ll say it again:Phil is the KING of the led´s!

once again,welcome back!

Greg

[leddwatch]

Hi Embie, thanks my friend, but if I'm the King of leds then surely you are the Queen....!