[V8] Instrument cluster fix - FIXED

[urq]

Good to hear that you were able to find a problem Ed! ... many times they
are not so obvious.

That V8 IC was the first I saw which had so many interconnections made with
pins and sockets on stacking boards.  This might work inside a PC, but a
vehicle?  I'll bet it didn't take long for VDO / Audi to change to a more
robust interconnection scheme and minimize the number of interconnections
between boards.  

Steve Buchholz

-----Original Message-----
From: Ed Kellock
Sent: Thursday, January 09, 2014 9:15 PM
Subject: Re: [V8] Instrument cluster fix - FIXED

Went into the IC again tonight. Short story is its fixed now. Yea!!
 
I had avoided removing the boards inside the first cover that you remove.
These two boards connect to each other through one small block of about a
dozen pins. About half of those were loose and trying to fall out when I
disconnected the two boards. I remembered reading about this exact thing in
one of the many emails I found that talk about this problem. It was from
Mike. I just never got the right idea in my head of this type of connection.
Now it all makes sense. 
 
Thanks!
Ed
 
-----Original Message-----
From: Ed Kellock
Sent: Thursday, January 09, 2014 7:30 AM
Subject: Re: [V8] Instrument cluster fix



Thanks Steve. When I plugged the IC in last night after more soldering
repair, the same issues remained. In the morning, everything wad working
okay, as it had done in the past. This morning, everything worked much
longer than it ever has, bit still all three gauges failed in the same way.
T Prior to that, the oil pressure gauge floated up to the peg once or twice
but returned to normal. 

It seems like the issues are improving as I do more soldering, but that's
not the result that one would typically expect. Definitely seems to vary
with temperature.

On Jan 8, 2014 10:53 PM, "Steve B" wrote:


I've got similar symptoms on #2.  While my opinions on the whys and
wherefores may be slightly different, I had done all the standard fixes and
yet it is still intermittent.  What I found was that by wiggling one of the
connectors from the car to the IC I could see the gauges react.  It has been
a while, but I think it was the yellow connector.

I think the problem is that the socket connections have worked loose over
the years.  My plan its to install longer pins on the IC and hope for the
best.  I can't imagine changing the connector on the wiring loom is going to
be a simple task.

You may want to try wiggling connectors as I did to see if you can identify
bad connections as I saw.

Good luck Ed!
Steve Buchholz





Ed Kellock wrote:

I know Ingo has reported that he did this and it corrected his issues as
well.

I have spent the last three nights doing this and still no change in the
behavior of my IC.

I still have dead fuel and temp gauges and a pegged oil pressure gauge. In
the morning they will usually be all working correctly, but within a few
miles, poof again. 

Really annoyed at this point.

Ed



-----Original Message-----
From: Mike Arman
Sent: Thursday, April 08, 2010 9:29 AM
Subject: [V8] Instrument cluster fix



>From 2005 posting:


> I had similar very symptoms on my V8 - fuel and temp gauges dropped 
> sporadically to zero, came back with a whack on the dash pads. The pc 
> traces were fine, the problem was cold solder joints at the pins that 
> the interboard ribbon cables connect to.
> 
> These are assembled by "wave soldering" - does the whole pc board at 
> one pass.
> 
> Problem is that if there's enough heat to solder the big parts (high 
> thermal mass), it is too much for the ICs and other smaller parts and 
> they get toasted.
> 
> I've seen this on other electronics equipment - *exactly* the same 
> thing, cold solder joints on the large pin connectors - PC power 
> supplies are good for that.
> 
> Cure is remove the cluster, take the boards off one at a time, and 
> with a fine pencil iron, re-solder the bases of the interboard 
> connection pins one by one. Put it all back together (now is also THE 
> time to change all the burned out dash lights) and dollars to donuts 
> your problems will be cured. I found four bad ones and some more 
> suspect ones. You will be able to wiggle (as opposed to flex) the pins 
> slightly in the pc board if the solder joint is bad. Also, a cold 
> solder joint is "grainy" or "pebbly" instead of smooth and shiny. Use 
> a magnifying glass.
> 
> Use some contact enhancer on re-assembly just as extra insurance.
> 
> I did mine almost two years (now SEVEN years!!!) ago, and that part 
> (at least) has worked flawlessly since.
> 
> Best Regards,
> 
> Mike Arman V8Q, lights, blinks, starts, runs (be afraid . . . )