wasabiskier

Hey all,
All of my instrument cluster backlighting died this weekend on my 97 A4 1.8TQM. It is not the bulbs but the circuit itself. The signal from the harness is being driven correctly but the lights are still dark. I am a EE so I tore apart the cluster to see if there was an obvious problem before I drop money/time on finding a replacement cluster. I am fairly certain the problem lies with a transistor/mosfet that has blown it's top on the board behind the Tach gauge. I suspect this is a FET that is driven by the inst. cluster computer to apply power to the backlight circuit. My problem is that half of the top is missing so I only have half the writing to figure out what part it is. There are a bunch of similar FET packages on the board but none of them end with the same sequence of numbers as the busted chip. The manufacturer symbol is a big "S" which is not STmicro but could be Siemens. If anyone recognizes it, let me know.

Anybody have a cluster out of their car and willing to read/send me the inscriptions on the part I am interested in?

Anyone have a dead cluster they are willing to part out to me for a reasonable price? (I am happy to pull the part off myself.)

Images for those of you who are interested.

<img src="http://my1.photodump.com/Anonymous/Chip Location 2-T.jpg">

<img src="http://my1.photodump.com/Anonymous/Chip Location-T.jpg">

<img src="http://my1.photodump.com/Anonymous/Blown Chip-T.jpg">

Thanks all,

Lorin

Nate (ETKA+Scumbag)

Those pictures 1. Don't show in the post; 2. Are WAY too small to be useful.

wasabiskier

<img src="http://pictureposter.audiworld.com/77344/chip_location.jpg">


<img src="http://pictureposter.audiworld.com/77344/chip_location_2.jpg">

<img src="http://pictureposter.audiworld.com/77344/blown_chip.jpg">

@wesome

just remove the .t to see the pic in fullsize

Nate (ETKA+Scumbag)

That would be a good selling point IMO.

Nate (ETKA+Scumbag)

Well, it was -T in this case, so I didn't think of that.

wasabiskier

DID? = Driver information display?

Everything else works perfectly except for the backlight. All gauges, lights, display (no missing pixels), etc. You wouldn't know anything was wrong until the sun sets and the lost backlight prevents you from seeing anything in the cluster.

Nate (ETKA+Scumbag)

Yeah, the screen in the middle of the cluster.