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Testing Digital Instrument Cluster

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Old 05-30-2014, 11:26 AM
  #16  
FLYVMO
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Took some pictures of the visible side of the circuit board, and found one of the top green connectors missing? The "lighting" board has two black connectors in the same matching location, but the circuit board seems to be missing one. Am I correct in that the board should have two green multi-pin connectors on top?

Also found what looks like glue and a soldered on wire in the lower left corner. Is this from the factory?

Cheers!
Carl
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Old 05-30-2014, 11:50 AM
  #17  
Rob Edwards
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Carl, here's the part # and that circuit board from Hebert's '91S4. You're definitely missing a connector, dunno whether your 'extra' wiring is factory or not.

I have a spare '89GT cluster at home, will pop the back off tonight and take a pic or two.

91S4 cluster for an automatic:



Old 05-30-2014, 12:11 PM
  #18  
FLYVMO
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Rob,

Thank you for the picture comparison. My board definitely looks like it went through some "mad scientist" lab at some point in its life. The screws are also filled with some white "goop". Hopefully the replacement cluster will have an unmolested circuit board to swap.

Cheers!
Carl
Old 01-18-2016, 03:12 PM
  #19  
mitche
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Default Waking this thread a bit...

I also have a dead digitial dash on my 1989 S4 928

Recently bought the car and have no info whats so ever, that said I'm dealing with one problem after an other.

Now I'm working on the Digital dash which is dead.
The dashboard lights up and the number for which gear is working, and the oil pressure is working.

Not working:
- Fuel gauge
- battery gauge
- temp gauge
- 3x digital display

Tested the bulletin here but it is only lighting up the bulbs, (all of which I have replaced with new ones)
Also tested as suggested, + on pin 1, without result used ground as described in bulletin.


Checked the fuses and relays, "refurbished" all grounds.
Took the CE panel and cleaned, and changed fuses and som relays.


Any ideas?
Who can I send it to, there are none for sale at the moment...

Mike


Originally Posted by FLYVMO
After about an hour searching for procedures on how to test the digital instrument cluster, the only one I have found is a snippet from tech bulletin 9302. Yesterday I powered up my instrument cluster but the information display is dead. I have changed all bulbs, and the only "life" I get in the cluster when following the tech bulletin is "Brake Light", "CAT" and 2 other warning lights along with the high voltage lamp and voltage indication on the volt meter, and the low gas light.

I have triple verified the bulbs, and the bulb traces, but the information display does not light up to show the mileage. Is there another test one can do to check that part of the cluster? Or is this the dreaded board failure?

Cheers!
Carl
Old 01-18-2016, 03:33 PM
  #20  
Kevin in Atlanta
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Where are you located? I have an 89 instrument panel you use to test.
Old 01-18-2016, 03:56 PM
  #21  
Ed Scherer
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Question

Originally Posted by mitche
Now I'm working on the Digital dash which is dead.
The dashboard lights up and the number for which gear is working, and the oil pressure is working.

Not working:
- Fuel gauge
- battery gauge
- temp gauge
- 3x digital display
So are you totally absolutely 100% sure that the fuse for the instrument cluster is OK? Do your interior lights work? On my '90 (and I think on a number of other model years), the interior lights and instrument cluster share a fuse, so if the interior lights don't work, that's a tip-off that the instrument cluster isn't working because the fuse has blown.

Some of the indicator lights in the instrument cluster will still work (even if the cluster isn't powered) because they are directly driven by external circuitry rather than some of the logic in the instrument cluster.
Old 01-18-2016, 03:58 PM
  #22  
FLYVMO
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Someone here on the list eluded to there being a repair shop in Europe (Germany I think), that fixes these digital clusters. Unfortunately I have never seen any concrete information regarding name or location. Would be great if it could be made public as I think there are no places in the USA that repairs them.

Cheers!
Carl
Old 01-19-2016, 05:26 AM
  #23  
Strosek Ultra
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This German company do repair work on 928 digital clusters.
Åke
http://de-en.kfzpix.de/porsche/porsche-928/index.php
Old 01-19-2016, 08:29 AM
  #24  
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Excellent! Thank you Åke!
Gott Nytt År

Cheers!
Carl
Old 01-19-2016, 12:57 PM
  #25  
mitche
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Default Some more info....

Well, all the fuses are OK.

However, when checking power to the fuses it doesnt look quite that good..

Basicly fuses powered via the C block is not getting any +.

For this example fuse 43, 44 doesnt get + and they are somehow involved in the whole #24 enigma...





No power to fuse 43 & 44, amongst other...

When I backtraced the missing + to F5 seen above i cant really see where it goes...




Does anyone got a better scan?

Although when I submitted 12 v direct to fuse 44, I did get a bit more instrument light - for example the fan regulator got som illumination.

Digital dash still dead....

To be continued...

Last question, you guys think I should start a new thread with all my issues and problem solving?

Cheers
Mike
Old 01-19-2016, 01:30 PM
  #26  
FLYVMO
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I don't mind if you post it here...it seems related. Keeps the amount of threads to search reduced.

Cheers!
Carl
Old 01-20-2016, 04:14 AM
  #27  
mitche
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Default Thanks...

Originally Posted by Kevin in Atlanta
Where are you located? I have an 89 instrument panel you use to test.
But I am sending my unit to Germany, the link that Åke has submitted.

Thanks again
Mike
Old 01-20-2016, 05:47 AM
  #28  
Strosek Ultra
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Originally Posted by mitche
But I am sending my unit to Germany, the link that Åke has submitted.

Thanks again
Mike
Please let us know how it will work out.
Åke
Old 07-01-2016, 04:37 AM
  #29  
mitche
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Originally Posted by Strosek Ultra
Please let us know how it will work out.
Åke
So, I got the dash back 350€ - problem still exist....

Doohhh
Old 07-03-2016, 09:53 AM
  #30  
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Default measure points....

Hello all!

Does anyone know how I can measure the connecting terminals to the dashboard?

I think my dashboard is OK, but I dont think its getting correct 12v somewhere for example fuse 39 is dead, but If i loop power to it some more lamps lights up..

Any ideas?

Mike


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