Synchronar 2100 Mark 3

[RFK42]

I bought a Synchronar 2100 Mark 3 with a deep dark red back. I got it around 1981. A year later it broke and the company sent me a new one. That lasted about 2 years and the led went dead again, so I put it away. I just now found it while doing some spring cleaning. The led is still dead, can this be fixed?

Thanks, Ray

[fronzelneekburm]

I bought a Synchronar 2100 Mark 3 with a deep dark red back. I got it around 1981. A year later it broke and the company sent me a new one. That lasted about 2 years and the led went dead again, so I put it away. I just now found it while doing some spring cleaning. The led is still dead, can this be fixed?

Thanks, Ray

It would need to be evaluated what the error is first. After resting in some drawer for 15 years you have a high chance the batteries have leaked and destroyed the inside. At first you'd need to take a look at the insides and estimate if there is still hope for repair.

[clockace]

and that particular model has open wire bonds on the chip. i have destroyed 2 of them trying to open them. prying them apart causes the gel to pull on the wires, which are smaller than a human hair. be very careful. not encouraging, but some have done it successfully. . i like the mkI/II's. more robust. peter

[RFK42]

Thanks gentlemen for replying to my problem of fixing this watch. Before I go any further, I want you to know that I am mechanically incline. I would like to know how you go about opening this watch. Should I use an Exacto knife or a razor blade or is there a special tool? Thanks. Ray

[Sully008]

Thanks gentlemen for replying to my problem of fixing this watch. Before I go any further, I want you to know that I am mechanically incline. I would like to know how you go about opening this watch. Should I use an Exacto knife or a razor blade or is there a special tool? Thanks. Ray

Welcome, Ray! Check out these threads for more info on the MkIIIs. These things are almost like the "Holy Grail". I have one semi-working module. It's nearly impossible to find one still in fully working order. There are a few here that have gotten them to work, though.

http://www.dwf.nu/viewtopic.php?t=2950

http://www.dwf.nu/viewtopic.php?t=2574

http://www.dwf.nu/viewtopic.php?t=2939

[retroleds]

If only they had covered the boards with epoxy.....well, hindsight is 20/20 as they say. And epoxy technology has came a long way since then - there was substantial shrinkage in the old epoxies, the new ones have very minimal shrinkage. I'd agree that the earlier models seem much more robust than the later ones.

[RFK42]

Well I finally opened the watch today and I found out that the batteries are housed inside an 1/8" thick plastic black housing which I managed to take the leaky batteries out and cleaned everything out. As I looked at the top half, it looked like the chip is submerged in some type of clear gel and all the hairline wires are connected. The only wire that I think is off is the hairline wire that goes to the LED display. I have taken close-up pictures of the inside of this watch. If anyone would like to see it and let me know if it can be repaired, please send me your e-mail address since I don't know how to add pictures to this site.

Thanks. Ray

[Synchroserious]

RFK42,Not sure what Ed is talking about with covering the boards in epoxy.Polyurethanee is the best potting material to use and makes the watch much more robust.

The MK III and MK IV modules are more robust in many ways then the older ones,but some have the opposite opinion.If the batteries are the only problem and there is no GE faulty Silicone inside then i agree it would be easier to pop open the back versus the more robust MK III and MK IV seal.Then replace them with NIMH batteries and seal it back in a less robust way.

BTW there are MK III chips inside a package on black PCB,s.I guess no one has taken one of these apart and taken pictures yet.It is important to remember there were about 6 different boards used during the Mk III era.

RFK42 you can send me some pictures and i could tell you more about what you have.

[retroleds]

RFK42,Not sure what Ed is talking about with covering the boards in epoxy.Polyurethanee is the best potting material to use and makes the watch much more robust.

Howard, I wasn't talking about potting, I was talking about maybe first sealing the wirebonds of the IC chip on the Mark iII and IV boards, since it is pretty much impossible to repair their wire bonds after the potting bath, so I'm thinking that sealing them against possible battery acid infiltration would have been nice - epoxy has a well known, better resistance to water infiltration than polyurethanes. Many of the MArk II/IV boards I have had had a pool of corrosion surrounding the IC, specifically - almost like the wirebonds made a little umbrella that kept some of the potting gel from making contact fully with the board there and a place for any migrating battery fluids to accumulate. But I understand there wasn't an anticipation of the batteries leaking, so flooding the entire thing with the poyurethane potting gel made sense. It was strictly a "hindsight is 20/20" kind of thought. Both materials are used today for potting of electrical components. Each have pluses and minuses. I personally seal the exposed wirebonds on almost everythign I get my hands on with slow-cure epoxy, both for longevity and so I don't have to curse myself for getting clumsy and damaging a wire bond when its wire-bonds didn't have an issue. World's strongest condom!!

[Synchroserious]

Ed,Yes in hind sight the wrong thing to do would have been to cover the chip wire bonds in epoxy as it would then be almost impossible to retrieve the chip and remount it into a IC carrier/package.With the silicone it enables one to go back in and repair other things much easier also than if it was blanketed in epoxy.Things are done for a reason.

RFK42, It looks like your MK III is beyond repair.The paper work offered to upgrade it to a MK IV which you decided not to do.

You will need a replacement module.Some 30 years later after the watch is a rare collectible it is more costly though.As an original owner i can still offer a discount to you.

Howard Riehl

[retroleds]

Howard, are you saying you are able to dig the IC chips off the boards and recycle them after they have been in the potting gel? I guess if no battery acid has gotten to them that might be possible. I understand you have opened infinitely more of them than I - my user experience has been 4 out of 5 are rotted all the way over to the chip, ones that don't have that kind of damage I've been able to get working. I'll drop out of this thread now - my presence seems to set you off.

[charger105]

I've got one of those MkIII boards with the sealed IC. The PCB is indeed black. I haven't got it to work unfortunately. I'll post a picture soon.

Rgds,
Andrew.

[Synchroserious]

Howard, are you saying you are able to dig the IC chips off the boards and recycle them after they have been in the potting gel? I guess if no battery acid has gotten to them that might be possible. I understand you have opened infinitely more of them than I - my user experience has been 4 out of 5 are rotted all the way over to the chip, ones that don't have that kind of damage I've been able to get working. I'll drop out of this thread now - my presence seems to set you off.

No, i am not yet able to do that but RWR had a way of doing it so it can be done.I remember back in 1989 i complained of not having chips in a package to work with and he proceeded to recycle some of the ones on board like people are used to seeing pictures of by removing them and placing them in a new IC chip package/carrier,re wire bonding and putting a lid on.From there i was able to solder down the package.BTW RTC did cover several groups of MK IV chips with a white epoxy prior to deciding to put them in a package/carrier.I have some but they are of no use if the board is corroded beyond repair.My chances of finding someone to recycle them with the rock hard epoxy is not as good as finding someone to recycle the ones covered with silicone gel.

As i explained in old posts the watches you purchased and opened were dead rejects from the start just like many others sold at the popular auction house.I sold you a group that were old trade ins that stopped working in the late 80,s and then sat dormant for 20 years(too long) before you opened them.

No need to be embarrassed Ed.It is better to ask questions than make conclusions sometimes that's all.

[retroleds]

So essentially you have had no more success at reclaiming the chips then the rest of us Well that sucks! I have nothing to be embarrassed about - apparently your father and I had the same thought and I never worked at the factory, so I am way behind on any possible knowledge. I'm thinking a lack of knowledge shouldn't be an embarrassment to anyone, but not applying what you know should be. Since retrieving the chips seems out of the question for either of us, I just voiced my thought that better protection ahead of time would be better than the possibility of recycling the chips. I agree that most modules I've bought had the test holes, which let in air, which greatly accelerated any acid damage. It's still a very cool watch. Don't be embarrassed about the leaking batteries - your dad's company didn't make them and had reasonable hopes of them lasting much better than they did. Life will be more peaceful if we don't have to keep poking each other over a difference of opinion on what could have been.

[Synchroserious]

Nothing to be embarrassed about is right,I just assumed the you posted meant embarrassed but i see it also means oops.

I forgot to mention that if someone only has a handful to work with your epoxy covering method may be the way to go to get some workers going.I'm just glad the masses were not done that way.After all you and others doing a few rebuilds don't permanently seal them so you can always go back in 5-10 years later before any corrosion may begin to damage the board.As mentioned on older posts it was not always the batteries at fault.

Here is a list of things that precluded the batteries leaking.(1),Poor Lexan molding done by an outside contractor permitted water and sweat ingress through cracks.(2),Defective RTV silicone from GE or in some cases the production manager(before my first stint in the 80's) went with a syrupy mix to avoid bubbles.(3),Then you have the ones with a defective seal plug hole by employees that did not understand it only takes a tiny drop of solvent to bond the plug in the hole.Rather they pored it over the plug in excess (weakening the seal and Lexan around the plug area)instead of prepping the plug and hole with solvent and immediately inserting giving it a quarter turn.Also if you don't wait 24 hours for full cure the plug strength can be weakened by someone trimming the plug to soon.All these things can lead to water,sweat ingress.Then and only then the batteries were forced to leak.In some cases like RFK42's photos it appears that the rubber seals on the batteries may have been degraded from poor potting but i am not 100% on that.Anyway over the last 20 years all of these possible flaws have been ironed out.

So in the end there are hundreds of chips to be saved one day(mostly MK III) covered in silicone when the time comes with an investor to pursue helping salvaging them.Otherwise getting new chips made would be even better but of course a much larger investment would be required.

Sorry for the long post and Ed i agree lets try to keep the chips off our shoulders

[J Thomas]

[RFK42]

What batteries can i use to replace the varta 50 DK in the Mark 3. And will they be leak proof. Also diagrams and schematics as i may try to fix this myself. I am a retired printed circuit designer.
Thanks, RFK42

[Sully008]

I wish I understood and had the tools to do what you just said here. I've got quite a few of those furry MkIIIs at home as well.

Repackaging those salvaged die is certainly a dooable task.
If you already have a ceramic carrier, and some legacy chip processing equipment (manual operation), die and wire bonding on a one-off basis could be accomplished inside of 15 minutes.
Also, an MEK or Acetone wash will completely remove the GE silicone potting from the die. The trick will be to perform a functional test of the die to determine if it's salvageable for packaging.

So I have to say it's a good thing that epoxy encapsulation wasn't used heavily in the MKIII assembly process. Maybe a few of the furry turds MKIII's I bought on ebay might be salvageable some day They're like little time capsules.

Jeff

[Synchroserious]

I had noticed RFK42 was a retired circuit designer on his profile here.I figure between him and Jeff all my confusion could be resolved.Hey RFK42 what do i do with the MK V CAD drawings ready for mask work? I have heard figuring out those drawings to make new chips may be easier,less costly than trying to reverse engineer the MK IV chip?

[RFK42]

Howard,

First of all, what CAD system are you using, i.e., CER CAD, P CAD, OR CAD, etc.? Also, if the drawings are ready for mask work, are you talking about solder mask. If so, the project is finished. Do you also have a drill drawing and assembly drawing finished? Did you check the schematics against the layout? If so, send them to a PC mfg. for a quote. A good reliable board when I was designing was a G10 glass epoxy. Are all the components SMD's? If I was designing the module, all the components would be SMD's, including the chip. That way you wouldn't have to encapsulate it in gel. There would be no hairline wires to worry about.
Thanks. RFK42

[J Thomas]

[fronzelneekburm]

Id say take good care of the CAD fies, these can take muuuuuuch time to make and are more precious than a physical mold or whatever as they can be reproduced indefinitely without quality loss! I have a small Roland Mill here which is unfortunately only suitable for plastics and wood,(wish i had one for metals) a small Roland Modela 3D plotter. But very usefull to make airsoft parts in small quantities.