Best LED module ever?

[T-bird]

Okay, guys.

I'll either get no replies or this will become a hot topic.
I was wondering about the level of quality in '70s LED modules. We all know there were different approaches in building them, and this makes the comparison difficult, but come on, everyone has a favorite.
I'm not talking about watches, just the modules, and their complexity, reliability and - speaking some 30 years after - longevity.
It seems that this kind of question has never been raised in this forum, I've checked back topics, but nothing. So, I'd like to hear from you all. Here's what I think:

TC modules:
I'm walking on a mine field here, I know. I love Pulsars, and I own five of them, but if you ask me if I consider the TC module the best ever made, my answer is no. They all seem to suffer, over time, and it's not easy to find a fully working module. The big P2 seems to be the most problematic of the bunch, but also working P3 modules don't come easy. On the P4, reliability seems improved, especially on the autoset versions, but again they seem to suffer from instability that often leads to excessive contact sensibility - the watch goes in autoset mode by itself, or turns on with the autocommand too easily or too hardly. As for complexity, the TC is the king of LED watches, with all of its features, like autoset, autocommand, reed switches, autodimmer, etc. Your opinion?

Hughes modules:
Again, great complexity - and great diffusion under myriads of brands, some famous some not. Hughes modules don't seem to be very reliable, though. Their construction technique, which didn't use a silicon covering on the wire bonds (the famous Glop-Top), makes them maybe the most repairable of the lot, but also the most prone to suffer from lifted wire bonds, especially in the display area (missing segments - relatively easy to fix) but sometimes also in the control unit (much harder). A former Hughes engineer told me that they didn't use the Glop-Top because they manufactured all of their modules in wet climates, were humidity was a relevant factor that didn't allow good curing of the silicon. This may explain why those few that had it (I think at the sideviews) often suffer from lifted wire bonds inside the covered area (not repairable).

Frontier modules:
These are my favorites. I still have to find one that is not working. They're not "simple" modules as well, since they were the first (or among the first) to incorporate an alarm with a piezoelectric capsule or a stopwatch function. They offer one button operation with day of the week, and even though their display has no dimmer, it is the brightest LED display I've ever seen, at least on '70s watches. Their only flaw were the electroconductive pads used to transfer ground contact from the buttons to the board, but once reversed or cleaned they often (always, in my case) work again. They have a very compact central unit which controls everything and it's enclosed in black Glop-Top, but as far as I know it doesn't suffer from it.

NSC modules:
The module that offered a dual time zone. It's also very thin, something that its makers extolled at the time on ads. Full Glop-Top, so it's unrepairable, but it seems to be quite reliable. Curious thing is that it has a dual layer Glop-Top: Black harder resin for the unit, soft clear silicon for everything else, also over the black resin of the unit. Not very bright, but decently shaped display.

Fairchild modules:
Again, a very honest module.
Once I repaired a Fairchild module whose board was craked in half - glued it back together, soldered the tracks (I had no silver epoxy at the time) and it worked perfectly from that moment on. Don't know much about them, but they seem to be well built - simple but well built.

Litronix modules:
Quite complex, look a lot like the Hughes, but without neither a Glop-Top nor a cover. The display area is covered by a bubble shaped screen, but the rest of the components are wire bonded and left exposed - a little delicate if not well cared for. And you know guys, how many "scientists" may have worked on or played with these watches over the past 30 years...

Sanyo modules:
Ah, I wish they were easier to find on cheap no-branders that sell for a few bucks on eBay. I've worn a Sanyo "powered" watch for twenty (20!) consecutive years without a single trouble. Built much like the TC but (please don't shoot me) more reliable. Simple - two buttons, two adjusters - is the perfect candidate for a transplant in a dead P2 or P3 module. It also has an autodimmer, but its display is not very bright and it's also a little tiny. But the module itself is bulletproof...

OK, I guess I've made my point by now. I have left out many important modules, like TI or Commodore. But I haven't had the opportunity to test them or see how they perform after all these years. If you have, go on and throw in your opinions. Feel free to say that I'm absolutely wrong, because I'm here to learn, not to teach. There are some of you out there that have a knowledge that I'll never be able to acquire, so I'd like to hear their opinion. After all, a forum is also meant to learn something.

What do you think?
Al.

[Majestyk]

What do you think?

I'll tell you what I think and it's different what you think. :)

The most reliable modules, in my 5 years of collecting and repairing, that I have come across, are the NSC's and the 29mm (most common) Hughes. Most of the problems of the NSC's are quartz crystal related because they used poor ones. They can be replaced very easily on this module. The same goes for the 29mm Hughes module but these have far less QC problems, which is good because it's much harder to fix. Only the earlier dot matrix ones suffer from occasional missing segments. The later ones rarely did. Because these modules were in so many watches, and I've found so many working ones, I have to give top marks to them. Now the smaller 25mm Hughes is another story. It was very poorly designed with QC not being affixed to the actual module.

For me, the worst modules in your list are Frontier and Fairchild. I have piles of these that are dead. Even when replacing the QC's they are still dead. If you open a watch with either of these modules and there are batteries left in, there is an 80% chance they will not work. Frontiers are also hit and miss when it comes to brightness. Many of them were not very bright, it depends which models they were and the factory they came out of. The ones that were in the 2nd generation Hamilton and Omega watches were the best for brightness but again, unreliable and many suffer from the second last digit being dimmer than the others, which is annoying.

Litronix are complete junk. I won't even get started on them.

Sanyo's are nice modules and very well built. I also have piles of these that don't work. The problem is when the batteries are left in; it just takes a little leakage to kill them because the main IC and wire bonds are located right under them.

I agree about the Pulsar modules. The problem with the earlier ones is they took 355 batteries. When those things leak, the fun is over. As for the later ones, it's like the problem with the Sanyo module. The batteries are right over the main IC, etc. So this is why so many Pulsars, from the beginning to the end, had problems.

One module that I also have to give marks for, that you didn't mention, is one made by Mostek and used in mostly Bulova watches. Those are tough modules and I rarely get one that doesn't work or can't easily be revived.

[Lordpulsar]

Lets face it... 30 year old electronics, the chances are they'll all fail some day :( .. As soon as the wire bonds oxidize, they will start to fail... The Oscillator circuits in the Pulsar's seem particularly susceptible... But my worst are by far Frontier modules...Then the Pulsar Calculator modules.... I dread them ! The rest, I think are on a Parr with each other...

[T-bird]

Hey!
Replies are starting to show, and from real authorities! :D

MJ: I take what you say very seriously. My experience is a fraction of yours, so your opinion is important. I guessed the Litronix were not great modules, but I've seen just a few. So they're junk.

I appreciate your opinion on TCs. Not many would dare to say that of a LED icon, but the truth is the truth. Yes, the Sanyo is built the same way, so I think that a module with a ceramic board that physically separates the batteries from the IC case is to be preferred - theoretically, but again that's no guarantee, since also gases are released during a leakage.

I'll definitely have to re-evaluate the Hughes modules. I've found a lot of them with problems from lifted wire bonds, and the Hughes engineer I've talked to told me that the first step was the Alumina board bond. It was made using a very small flame. Then, the second step was the semiconductor bond, and this somehow could weak the board bond, if that wasn't 100% perfect - a possible failure source. They also used to cycle the modules through temperature extremes, to simulate ageing, and lifted bonds often occurred. But statistics must be taken seriously, and if you say the percentage of working Hughes is great, I believe you.

The NSC I've come across suffered from bad QC, as you said. I agree it seems a reliable module. Don't know about the Fairchild, it looked tough, but if you say it isn't anything special, I'll have to reconsider. As for the Frontier, both you and Simon seem to hate it. I really don't know what to say, it is a matter of good luck in the end, but I have come across many of them and I still have to find a dead one. The classic 2005, in particular, is hard to kill. It came in all later Hammys, and its only flaw was the aforementioned weak conductive pads used behind the pushers. Aside from that, it looks bulletproof to me - I've even used one on a P2, and it's working great. Intense brightness, too. Anyway, it may be that one model in particular. If you say they're not very reliable, I must rethink. Yes, I also know the Mostek module, but I've had just one. It was perfect, but its weird date/seconds combination didn't look very smart.

In the end, what Simon says is the sad truth: we're dealing with 30 years old stuff - but I think this is not the main problem. The biggest trouble is that all of this stuff has NOT been in OUR hands in the last 30 years... You know what I mean...

Come on guys, this may be a good "consumer guide" topic. Send in your opinions!

Al.

[retroleds]

I'd agree that the Frontier sufferes from weak contact point - weak physical construction - good otherwise. Ditto on LItronix - I hate the battery contacts and apparently the consumers of the world are confused and frustratred by them. 29mm Hughes - strudy and relieble, 25mm HUghes: reliable as long as you don't have to physically handle the module...the QC(as MJ mentioned)was oddly mounted so if floats free of the main circuit board - and damn hard to fix when it breaks free.! Nation Semies: I love them, their only real weakness is in the QCs they used...I have fixed uncountable numbers of them through simple QC replacement. Bulova(round): I think they are good quality, generally suffering from bad QC's,but their real drawback is how they interface with the case crystal(red) - that damned notched design of theirs makes it virtually impossible to retrofit anything into a Bulova case. Early PUlsar/Hamilton and Omegas: all problematic with their reed switches, but glorious in a working model. Synchronar: elegent electronics design, Years ahead of it's time, but the construction of a totally sealed device that must be destroyed to be opened for repair :? , should the QC go bad(yes, it does utilize a quartz crystal, just not a trimmer for compensation), the batteries fail.... Don't bother beating me up on this guys(I won;t really respond)...I'm on parole for "poison penning on dwf" and can't afford another infraction. 8)

[T-bird]

Hey, thanks Ed.
You give me back some hope with Frontiers :wink:

Come on, guys - Andy? Bruce? This really seems to be a possible "LED module consumer's guide"!

Al. :D

[fronzelneekburm]

I dont share the oppinion with the hughes modules. WHile some are very sensible to static and humidity I have made very good experience with the Dual display hughes module. My Longines Gemini II features the Dual display LCD/LED hughes module and its by far the most accurate module I have ever posessed. I virtually never adjust it besides when battery are renewed (approx. 2-3 years battery life). I wear this watch nearly every day and I even once forgot to take it off in the shower - and HA: It still works (although the watch is NOT water resistant). :D

After 30 years I think you cant say its not reliable. However I am aware that there are "worse" hughes modules.

Also when it comes to tech I am quite impressed by hughes programmable message module, I have 2 watches featuring these and I like these a lot. Then there is the hughes calculator module. While not one of their most reliable ones I think it clearly shows that hughes is among the "inventors" in LED watch Hall of fame, not on the "tech stealers" like 95% of the other manufacturers.

The worst modules by far are the Frontier and Fairchild. The frontier Modules I had working all turned "broken" suddenly over night, they just died without further notice.
Fairchild modules tend to "just go mad". I remember the Tiffany watch from my mum, I had cheanged the module 2 times and the third module seems to be running fine, but it drains the battery empty after just 3-6 months - my mum was wearing the watch about 1 or 2 times in such a period, so she was quite glad I gave her a Seiko "Le vent" in exchange. Not a vintage model, but she loves the style and reliability. Ah women can be pleased so easily... :D

Litronix: They are for sure cheap crap, but if they work then they just work.

NSC: May be the fact that they are among the most spread modules out there, but I never had more broken modules than from NSC. They seem to be made quite well, but when you want to start collecting dead modules, them my advice would be: Start with NSC, easy to get hold of many dead NSC modules.

TC Modules: Probably the most interesting ones, but also quite sensible. Well, only the fact that so many of these still work today (Quite a small wonder) keeps me from saying anything bad about these. Just be cautious when handling these, some of them are among the most expensive modules.

Sanyo: I only have 2 watches using Sanyo modules, but they are both working well. One is the green compuchron which is a quite interesting piece. Maybe not among the best, but also not among the worst.

Sinclair: Argh, I fear these. If yours is running, then dont touch it!

Texas Instruments: Among the worst crap I have ever experienced. While many of them work they suffer from being built very cheap. The TI modules are the only modules I sometimes had to modify just to enable them to get contact. Its for sure a good attempt to have a completely own design of a module, but especially the pushers on the module are a design fault. Too often there is a half milimeter missing between contact and module. Well if you arent having problems with the contact they are still a quite reliable module. VERY sensible to leaked batteries and moisture.

[retroleds]

Just a brief add-on to fronzels: The big problem with some Fairchild watches(and most Trafalgars) - odd diameter and/or contact pattern modules. Maybe not a true "module problem", but it really sucks for those maintaining watches. Fronzel: you find a 26mm 2/4 module for my Fairchild, I'll give you two Dual LED/LCD Hughes :D Or how about trying to find a module for a Saturn LED with their 29mm,2/10(setter) modules...
THIS has been a great topic!!

[fronzelneekburm]

OK, Ill see what I can do. The one module I am sure its working is unfortunately built in a solid 14K gold tiffany, I really want to sell that watch working.

But maybe I might have one as a spare, I bought all I could get as this was my mums favorite watch. Well she's happy now with the Seiko Le Vent and an Avia Pendant watch. :D

That Saturn could get tough. I will see...

[azimuth_pl]

Nice topic, found it when it's all over (almost).
Strange to admit but I love the Frontier modules especially the 2005 which is among the brightest, whereas the 2002 is the best donor for Pulsars P2 and P3 with the identical dot-matrix display. (Better than Sanyo and can be used as display donors for Pulsars).
Yes, they are sensitive and don't like manual intervention. I guess this is caused by the silicone covering a big area on the front of the ceramic board. Once you press it even slightly, the silicone "moves" and might damage the IC wire bonds. Also the silicone was not resistant to battery acid.

As for Pulsars, they were nice but not very complicated (some plastic and a few wires). Compare them to the stem-set '75 LCD Seikos which had brilliant, technically artistic modules.

From rare pieces, I have to give credit to Orient Japan modules (pretty complex and perfectly made) and Russian Elektronika LED (the first modules had the micro wires bonded manually on the display ??!!!)

[alexbe]

i won't tell about longevity, but visually i like these most, they are eyecatchers )

[retroleds]

Those are very nice...clean lines.

I've always thought the Mido module was an interesting construction.



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[Steef65]

Can anybody tell me what module this is?

[Huertecilla]

My favourite would be the Elektronika 1.
Conceived in 1978 it made use of tried and tested designs.

The module evolved untill 1993 when poduction stopped because the whole factory ceased to exist and was stripped.

The third generation of the module must surely be the best LED module ever produced.
It did not switch to a cheaper design as it was basically never redesigned and still features a trimmer, only became more rugged.

[Huertecilla]

The last generation Elektonika 1:



Foto: crazywatches.pl

Look at the hybrid LEDs

[rewolf]

Nice module.
It's quite complex: there appear to be 3 chips under the larger green blob, probably oscillator/counter/control (upper right), BCD to 7-segment decoder (upper left) and digit driver (bottom). In 1978 the rest of the industry already used single-chip designs (and no more LEDs anyway).
Any idea what's under the smaller green blob? Could be oscillator-related.

[Huertecilla]

Any idea what's under the smaller green blob? Could be oscillator-related.

It is; it´s the exciter/repeater.

The three ic´s are the divider a driver and most likely a regulator connected to the trimmer on the reverse side.

This module is a combination of tried and tested archetypical early seventies designs with the functions separated, but made with mature electronics products.

[retroleds]

It has that hand soldered look, but I suspect the solder is actually a resolder job...someone trying to nail down a sporadic fault.

[Old Tom]

The upper blob next to the crystal is the oscillator chip. The three chips under the lower blob are the main timekeeping chip, the digit driver chip and the segment driver chip- all very Nat Semi style early chippery (I suspect they were reverse engineered NS chips like so much Soviet iccery). The reason all the functions were separated was twofold- early on putting "power" transistors onto the main chip proved quite problematical so easier to produce separate driver chips for different output loads- in theory the same main chip could have been used with VFD or even nixie driver chips. Separating the oscillator chip gave better accuracy (in theory!) but soon realised not necessary at micropower levels involved.