Audi 200 1991 10v tqm

[Hayes Myers]

Thanks Mike (and all who replied).  Job certainly looks doable. (and the
things you state make sense... I'm in Printed Circuit manufacturing
industry... so our customers have the same issue during assembly although
one would think wave soldered press fit connectors wouldn't be such a big
deal. )  Detail on what size solder iron and solder to use is excellent
feedback... will certainly save me hunting for replacement to fried cluster.

Cheers!
Hayes

-----Original Message-----
From: Mike Arman [mailto:Armanmik at earthlink.net] 
Sent: Tuesday, December 16, 2008 9:16 AM
To: quattro at audifans.com; hayesmyers at gmail.com
Subject: Audi 200 1991 10v tqm

> "Hayes Myers" <hayesmyers at gmail.com>
> Subject: Audi 200 1991 10v tqm

> 
> Speedo gauge works intermittently, sometimes it bounces..sometimes it is
> dead on the speed.   Tach is much worse.mostly not on at all.  I gather
this
> is typically solder joints on the gauges? 


On the V8 models, typically the problem is the edge connectors between the
various PC boards. the 
connectors are a row of pins, they slide into a socket on the next board
over/up (this will be 
obvious once you have the cluster on the bench). There's no problem at the
connections between the 
PC board and the instruments themselves, so if you only look there you'll be
barking up the wrong 
tree and will have to do the job again.

These connector pins often have cold solder joints. You can see this with a
5X magnifying glass, the 
solder joint looks greyish and grainy instead of shiny and smooth. The pin
may even wiggle in the PC 
board, if so, that's your smoking gun. Root of the problem is these boards
were wave soldered, if 
they turned the heat up enough to get a good solder joint at the larger
connector pins, they'd melt 
all the ICs. If they kept the heat low enough not to melt the chips, they
got cold solder joints at 
the connectors.

A 30 watt (MAX!!!) soldering pencil and some ROSIN CORE electronic solder
will fix you right up. Be 
careful not to make solder bridges between adjacent pins. Just a TOUCH of
the soldering pencil and a 
DAB of solder at each pin will fix you right up. Takes perhaps half an hour
to do and check all of 
the usual suspects.

If you're really, really nervous about this, contact me off-list and we'll
talk about me doing it 
for you free, you'll owe me a beer or something . . .

Best Regards,

Mike Arman
86 5K CS/5spd (gone)
86 5K TQ (gone)
86 4K CS/auto (gone)
90 V8Q yeehah!!