[sdiy] Xpander repair help

[Scott Juskiw]

I'm quite certain it's not a PCB problem. The display sits well above 
the PCB on 58 leads making it easy to clamp an oscilloscope onto any 
pin after the solder point. The signals on the pins are always there, 
they just don't seem to get into the VFD. I've also resoldered all 58 
connections, bad solder joint was my first guess, but that had no 
effect. Hence why I started looking for bad connections within the 
VFD.

I've also tried cooling the display and that makes it work too. Too 
bad it won't work at (or near) room temperature. Well, winter's 
coming, maybe I can play it outside.

At 7:19 PM -0800 2004/08/22, Jay Schwichtenberg wrote:
>Scott,
>
>Could be the display but it could be a bad connection or broken trace on the
>PCB.
>
>When you are heating up the board things will expand and make broken traces
>come together or bad connections become solider. I would give a good visual
>inspection (good light and magnifier). Then if I didn't see anything I would
>take something like a tooth pick (sturdy, non-conductive) and push solder
>joints, PCB traces and on connectors to see if something starts to work. Be
>careful and don't break anything.
>
>Jay S.
>
>>  -----Original Message-----
>>  From: owner-synth-diy at dropmix.xs4all.nl
>>  [mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Scott Juskiw
>>  Sent: Sunday, August 22, 2004 4:28 PM
>>  To: synth diy
>>  Subject: [sdiy] Xpander repair help
>>
>>
>>  I have an Obie Xpander with two flakey displays. I've got the service
>>  manual, I've got a scope. All signals going to the displays are fine.
>>  It looks like there's an intermittent connection inside the display
>>  itself. If I point a heat gun at certain pins the display will work
>>  perfectly. But as soon as it cools, it stops working. I'm a bit stuck
>>  trying to figure out how to fix this. Is it possible to get
>>  replacement displays? I know VFDs are still being manufactured, but
>>  are there any drop in replacements? I couldn't find any.
>>