let's bond some led watches!

[Kasper]

http://www.benl.ebay.be/itm/K-S-Kulicke ... 3f16257904

[retrowrist]

Kasper,

Please don't take this wrong, but do you know how to operate this bonder? If so, then you would be adding even more knowledge and experience to an already knowledgeable brain.

- Patrick

[Kasper]

it's not that difficult to operate it but what do you ask for doing it. First you have to find the problem in the watch, then open it (delicat and difficult and not always a succes). then do the bound and reseal everything. This is in the best case scenerio when nothing goes wrong with a watch that is more then 30 years old.

so you can not give any garantees at all...then the price of the bondingmachine. so even if you want to do it...you could not make a business of it.
So now with less time to spare with the new baby, i have to skip it.


EDIT :IF IT WAS one year ago..., yes..i WOULD HAVE bought it..just for fun and knowledge. And bond some watches for a cheap price for all you forummembers

[Brendan]

So .. what is bonding anyway ?

Looks like micro-surgery, sounds like glue.

[retroleds]

I'm surprised that Hanno is selling it off...along with the NOS Synchronar displays I sold him, still in the same box. Odd.

THe #1 bond failure is from the LEDs to the board traces. Due to the multiplexing of the displays it is usually very easy to determine if it is a segment driver fault vs. a segment to trace bond fault . 99% of them can be visually seen at 20X or greater - if only one end of the bond has lifted they can be fixed with a decent success rate by [steady] hand. Akin to "painting a piece of string, using a softball that has been rolled in paint" - even the smallest droplet of silver epoxy looks huge compared to a wire-bond.

[Adam]

Im lost, is Hanno Kasper and SASM? Sorry if its not but it looked like you owned the bonding machine Kasper.

Adam

[Kasper]

oops sorry if i gave you that impression..i don't own it..but i know how it works.

if you do a littlle search on youtube you can find a lot of interesting clips on bonding. And i have opened a lot of led modules to have a pretty good idea how to do it.

damn my english must be getting worse

[retroleds]

Yes kAsper, it sure sounded like you were implying you were !nicole/Hanno. Moderate yourself man!

THe display faults - due to multiplxing there is one common to an entire character (not segment), and one separate "hot" to each individual segment. The same segment on ALL characters tap into the same trace on the board. And the "common" connection is extremely hard to be damaged, since it is usually underneath the entire charecter. SO, if an entire character is dead, it is probably a bond from the display driver down to the board. If an individual segment is dead, it is probably a bond from the segment to the board. If the same segment is out across all characters, it is back to a driver to board issue. That analysis will sort out 70-80% of display issues. Sometimes bonds that look fine are actually lifted just a hair - i poke them(seriously) with a single fine hair pulled off of my dog, which is glued to the end of a wooden toothpick. That is actually very good for applying silver epoxy too, due to the small barbs along most dogs hair. The hair is soft enough to not break off a loose wire-bond, unless you really got clumsy. And you should have a surface at the same height as your microscope to support your entire hand so your fingers are doing all the movement....learned this from a fine oil painter I worked for...watching him paint eyelashes one at a time. http://www.richardmiller.com

[bucko170]

....... Sometimes bonds that look fine are actually lifted just a hair - i poke them(seriously) with a single fine hair pulled off of my dog

Ed, I think we might be working you a bit too hard

[retroleds]

Please don't report me to the authorities.