Mark I - Problem after problem... with no end...

[renozumi]

Hi

With full of enthusiasm I started to repair my Synchronar Mark I. I changed the batteries, the ic, the qc - then it worked but now I have a problem with the display.

http://www.majhost.com/cgi-bin/gallery.cgi?f=213535

Has anybody else a tip what I should repair now? I there still some hope or should I cancel my project?

thanks to all and bye
Reno

[Sully008]

Reno,

Pm me your email address and I'll send you the schematic.

Mike

[renozumi]

Hi Mike. You can email me at rzbuy@bluewin.ch

Thank you!

Bye
Reno

[Sully008]

Email sent. Hope they help!

Hi Mike. You can email me at rzbuy@bluewin.ch

Thank you!

Bye
Reno

[charger105]

Hi Reno.
Looks like you're making good progress with your project. Don't give up now

Try to figure out if there is a common segment out across the display (by advancing all the digits). If they're not common, then the display is probably rooted and you should think about changing it.
To remove, I lay solder braid across 4 or 5 joints at once and then apply heat......it soaks it up like a sponge.

Rgds,
Andrew.

[renozumi]

Hi Andrew

So you believe that not the transistors are corrupt? You think it's the display? I have a few spare parts - see picture:

http://www.majhost.com/cgi-bin/gallery.cgi?i=2413392


What you suppose to change? Is it difficult?

Thanks
Reno

[Sully008]

Reno,

Usually if it's random segments that are missing it's usually the display that's toast. I have a module that is missing the upper right segment across the entire display. That one needs a transistor replacement.

With yours I would remove that one and try the display on the right in your picture. Don't cut the legs off the display yet, but hold it to the contacts of the module to see if it all lights up.

Hi Andrew

So you believe that not the transistors are corrupt? You think it's the display? I have a few spare parts - see picture:

http://www.majhost.com/cgi-bin/gallery.cgi?i=2413392


What you suppose to change? Is it difficult?

Thanks
Reno

[renozumi]

Hi.
What's the best technique to desolde the display? From witch side do I start? I suppose from bottom, the side where I can see the transistors?

Bye Reno

[clockace]

reno, one thing you need to keep in mind is that all of these pcb's are used and they were returned because they malfunctioned. you will not be able to get all of them to work. of the ones i have repaired, i started out with sealed modules that i bought from howard. they had not been reopened. that at least gives you a better chance to get a working one. i got a total of 11 from howard. out of that i had 1 that is trash/parts. the other 10 i did get working, but only 6 of them are working well. the other 4 have various problems. won't keep time, won't set properly, etc. 2 of these work well, but they short out and stop after awhile. i think mike had some with that problem as well. . when i powered up all of mine, if i could not get a complete display i first changed the qc. i also changed the 2 cell wires to make sure i had good connections. on those that had segments missing, i used the schematic to see which transistor drove that segment. check the traces from the chip to the transistor. i only had 1 that actually had a bad transistor. i have a post on changing that as well as photos on the gallery. i was successful on changing that, but i don't know if i could do it again. probably beginners luck or the fact that no-one told me i couldn't do it. remember tho', i started out with sealed up modules. you received mostly bits and pieces out of a reject bin. not to discourage you, but you have some really nice clean pcbs with the chip already there. i would have started with one of these and added the display and qc. you could still do that. in my opinion there is too much wrong with the one you are dealing with. do you have the proper equip for the soldering and unsoldering? i used a small battery powered called "iso-tip". it is rechargeable and uses very tiny tips. you should also have some small alligator clips[smooth jaw] for a heat sink. wishing you the best. peter [edit] after a discussion with andrew we have agreed it is probably your display that is bad. peter

[renozumi]

Hi Peter.

Again - thanks for the tips.

What are the really essential parts (qc, ic, display, board...) to test, if a board works? I have the problem, that I have no more qc. Is there a newly product that I can buy from a standard manufacturer ?

Bye
Reno

[rewolf]

Practically any standard watch QC with 32768Hz will do.

[bucko170]

Plenty of cheap ones available on eBay

Bag of 200
http://cgi.ebay.com/200-32-768-KHz-3276 ... 27ac5ec2bf

Bag of 50
http://cgi.ebay.com/50-32-768-KHz-32768 ... 3ef1f54b86

Bag of 10
http://cgi.ebay.com/10x-New-32-768KHz-W ... 3a4d9741f4

Or try electrical stores such as Maplin.

Keep up the good work Reno.......I reckon you will get one working!

[renozumi]

Great!! Thanks for the links.

To try If a board works is it enough to have the ic, qc and the display? What about those tiny "towers" at the corners and the screw behind the display?

Thanks for all the motivation - Keep in touch!!

Bye
Reno

[rewolf]

The "screw" is the trimmer (variable) capacitor. It is used to fine-tune the oscillator. It can be replaced with a small fixed-value capacitor of ~15pF (picofarads). This has been discussed soewhere in this forum recently...
(update: here and here).
Not sure what you mean with "towers".
All components on the board are required for the watch to work. This inlcudes driver transistors (black), surface-mounted (=SMD) capacitors (brown), SMD resistors (white), and through-hole-mounted resistor (brown cylinder with colour stripes). The resistor is part of the oscillator.

Then, there's a diode and additional resistor as part of the charging circuit. These are not required if you feed the module directly with 3V and don't want to charge it with the solar cells.

This old thread has some good information and images of the MK I: http://dwf.nu/viewtopic.php?t=2180