What is involved with restoring missing segments...

[Majestyk]

What is envolved with restoring missing segments with Pulsar P2 modules? There are no accessible wire bonds with these modules, so is it the entire display that has to be replaced or does it have to do with the row of transistors (or whatever) above the display?

Thanks!

MJ

[kc8adu]

if the same segments are out on all digits its a driver issue.
but one out in only one digit is an led/wirebond failure.

[Majestyk]

It's the same segment(s) on all the numbers. So I'm assuming the drivers are the row of 7 transistors (as I'll call them) at the top of the display.

How would I remove them and how could I put a replacement in (from another dead module) where the old one was? I'll also have to figure out which driver controls which segments.

Thanks,

MJ

[kc8adu]

i would need to see it.
one could test each transistor with a vom.

[Majestyk]

Once I localize which ones are the culprit, do they have to be replaced?

[rewolf]

Unfortunately, I don't know what the P2 module looks like.
Can you post a closeup pic?
Is anything printed on the driver transistors?
Are the transistors in a standard SMD plastic package, e.g. SOT23?
If so, they can be replaced easily. Almost any transistor of correct polarity (NPN/PNP) should work.

Does anyone have a circuit diagram of the P2 module?

[Majestyk]

Unless someone beats me to it, I'll post a pic shortly, thanks.

[azimuth_pl]

Guys!!!!!!
The subject with missing segments has been mentioned at least 3 times on this forum:
http://digital.superman.ws/phpbb2/viewtopic.php?t=1063
http://digital.superman.ws/phpbb2/viewtopic.php?t=982
Detailed pics of modules are shown in the thread above and also on my website:
http://crazywatches.w.interia.pl/photo/ ... _tech.html

[embelton]

Azimuth:Nobody digs up old threads like you!

[azimuth_pl]

:) what's the use in keeping old threads if nobody is reading them anymore. if one thread is already present, then why does the same question appear 3 times.

[rewolf]

Why don't poeple search before they ask?
This question is as old as message boards...

[andyz4000]

Azimuth have you ever attempted re-connecting a wirebond to the IC? I have done a few where the wirebond joins to the PC Board with no real drama but the IC looks scary though my little 10x eyeglass :(

[azimuth_pl]

howdy,
I have tried this a few times and have been successful 90%.
This solution works (if you do it properly) on all P4's, Sanyo modules and some Bulova Drivers N7 in which the IC is covered with a plastic plate instead of epoxy. Usually when the same segment is missing on all digits then the IC bonding needs to be checked and repaired.
A microscope can be useful but I did well with a watchmakers 10x eyeglass. It can take a while to get it done perfectly.

[seansmiller]

Azimuth, are you saying that you have done repair job on a P4 module with missing secments, and been successful?
I have a P4, 403 DOW module with missing segments:
http://dwf.nu/viewtopic.php?t=1107

I've also asked several other Led-tecs on the web, and they gave me the same answer: It can't be done!
I still have'nt got another module for my Pulsar, and it really bugs the Sh*t out of me

If you think this might be fixable for you, please PM me.

[andyz4000]

I must try it then, P4 (PC board contact) and Bulova displays are fine and give me no trouble but I have a Bulova single button Driver with 2 wirebonds missing alltogether, the IC on the reverse side of the display is really small so I have shelved it for another day. Man you must have a steady hand, I am making up a clamp and have a miniature lathe part so I can dip the wire in Epoxy and zero in on the IC at less than 0.1 mm progression for a perfect landing, the problem is my 10x makes it hard to see whats going on

[azimuth_pl]

I've got a pretty steady hand as I also work with mechanical watches. However any kind of support for the wrist is helfpul.
In reference to the post by seansmiller a P4 type display might be repaired if only a few segments are missing. If most of them are gone then it's unlikely to repair it. The biggest problem is to remove the display from the module without doing more harm. Very tough job.

[andyz4000]

My Microscope finaly came in and its so much better to use, I rebonded a couple of wires on the back of a Bulova Drivers (newer model has a cover). I can bond to the IC by just placing a small amount of bond on the end of the wire and moving in with a mini lathe driver until it touches the contact area.
I did a test run and it works great but the problem is getting very fine wire, the strands I used were a bit too fat.


Pictures of my first attempt, I overdid the first blob but it cleaned up ok.

[oldpulsar]

Azimuth, are you saying that you have done repair job on a P4 module with missing secments, and been successful?
I have a P4, 403 DOW module with missing segments:
http://dwf.nu/viewtopic.php?t=1107

I've also asked several other Led-tecs on the web, and they gave me the same answer: It can't be done!
I still have'nt got another module for my Pulsar, and it really bugs the Sh*t out of me

If you think this might be fixable for you, please PM me.

It can be done,I have done this hundreds of times!!

[Planet-LED]

Andy,

What strength magnification did you use and what brand of microscope? Thanks.

[andyz4000]

This is it here :wink:

http://cgi.ebay.com.au/ws/eBayISAPI.dll ... 7578369589

[azimuth_pl]

That's an expensive investment ;)
To get an idea of the difference between the early N6 and late N7 Bulova drivers circuit board. The later model had a coverplate: