Help with a couple of LEDS please

[Adam]

Its saturday afternoon and imbetween Gardening Im playing around with some LEDs that have been sat in a drawer for ages. This was going to be help for three LEDs but after a clean a very nice General Eelectric stopped just showing a one and a colon and kicked into life.
My problem now is a plutron and a linotronix both show some life but not much and the linotronix only when make contact between the broken contact and the battery. See photos below.
My question the Litronix needs to be taken apart to be cleaned, it doesnt look as easy as othe modules Ive taken apart, has anyone else tried this. Also the Litronix has four buttons(one depressed) this seems a lt for an LED does it have some extra function?
The Plutron only shows one digit at the end dependent on what contact you have. Sometimes a 1, a zero or an H. Any ideas?
Apologies for the dirty fingernails they are not usually that bad. i can only blame the gardening.

many thanks

Adam

[retroleds]

Adam: The 4 contact Litronix has a tip-switch for tip-wrist function(greenish square showing above display in your picture). The fourth contact was under a push/pull button that would stay in postion (not spring loaded) so you could choose if you wanted the tip feature on.

If you pop the top off that module you are immediatly seeing exposed wire-bonds...in fact, if you get at all clumsy whilst taking the top off(snap on) you will rake those bonds and certainly ruin some. I'd suggest coating with clear epoxy before proceeding, after visual examination at 10X or greater to see if any bonds are already mashed or torn. Yes, the battery contacts make crap contact witht he board - some people dab them with solder flux and then a quick dot of solder, others try to work a little silver epoxy in/around/under the contact point - I've done both and results seem close to same. Hardest thing to get is the correct crystal. It's the common 32,786 hz, but it has a third wire "exciter" for the crystal that is also used to take current to the circuit. Statek company is the only one that made that style crystal. Kind of screwy...good luck.

?You understand the current path from the one module clip contacts the case so the buttons are part of the circuit, since the batteries themselves are normally insulated from the case.

[Adam]

Thank you for the quick reply retroleds
I think I might leave that one as it sounds a bit scary for my first play around. I need to do some more studying and practice before I ruin a good watch. Remember I'm only used to playing with LCDs they are easy in comparison. I did notice the Plutron wires were completely uncovered so I put the top back on quickly as I had read previous post were modules were ruined by clumsy newbies.
I have had some luck but only with cleaning(Trafalgar, Bulova and the General Electric plus one more but thats missing some segments(are these easy to fix?)) unfortunately not the ones I wanted to get going these were the litronix and a Sicura.
You have some great articles and how to here. I think ill go off an study them some more.

many thanks

Adam

[retroleds]

I might leave that one as it sounds a bit scary for my first play around.

You are a wise man to wait until you feel your skill set is ready for them.

In answer to your question - no, wire bonds are not easy to fix, but not impossible either(even without a wire-bonding machine). But you do need 20-40X, a steady hand and the right tools and materials. A binocular dissecting microscope is fantastic for that work.

[Adam]

I'm not sure I meant wire bonds unless that the reason the led is missing some segments, for example the middle bar under the zero. I've got a couple of images for your site that you havent got if you are still adding them. The digitime boxed, The General Electric and Im not sure you have the gold Litronix. let me know if you want them and ill send some over next time I do some watch shots.

regards

Adam

[Adam]

Retroleds
What do you use to magnify when you are working. I think its about time I invested in something better than a magnifying glass. Also I have a couple of solering irons but how fine a tip should I be looking for?

many thanks

Adam

[retroleds]

For wire-bonds I am using an "AmScope" brand(cheap, $300?, Chinese, very adequate) binocular microscope with two magnification choices - 20X and 40X. I primarily use 40X(with my reading glasses off). For general work I use a magnifying visor that gives me 2X(plus the reading glasses) or 4X plus the glasses - generally just using the 2X. A 15-18 watt soldering iron is very sufficient for most watch work.

I use silver epoxy for wire-bonds....along with some tools and techniques borrowed from my toolmaking days.

[Adam]

?You understand the current path from the one module clip contacts the case so the buttons are part of the circuit, since the batteries themselves are normally insulated from the case.


Hi Ed, keep coming back to the LEDs and looking at this thread. Ive ordered a magnifying visor now as the looking through a poxy magnifying glass all the time was driving me nuts.
I dont really understand the line above, do you mean the module I showed with just a number 1 showing?
The Trafalgar that was working is now not all it does is when touching the two batteries lights various digits up. This was after I had cleaned the board when it was working correctly. Any ideas what I may have damaged?

thanks

Adam