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Discussion Starter #1
Your tech articles on the radios and such have been outstanding. Have you had a digital dash cluster that's used in the 87 through 89 LeBaron Premiums and some Daytons of the same vintage apart for evaluation ?

I have several malfunctioning clusters. One where the VFL display is totally dead, another where the T,V,O gauge readings (temp, voltage and oil pressure, all share the same single bar graph display)are very erratic and jump all over the place and yet another where parts of the VFL display illumination vary light and dark in horizontal bands across the main part of the display. Sort of like the display is driven from two voltage sources and the voltage is applied in alternate horizontal axis'across the width of the VFL tube.

In all 3 cases the problem is within the cluster as substitution with a completely functioning cluster works perfectly. I've had these apart and looked over the pcbs for cold solder joints, hairline cracks or overheated areas and didn't find any. I used a magnifying glass but maybe I should find one with more magnification.

Have you any experience with these ? The IC's are not well identified and I was thinking that I could take the three of these and make one good one if I could determine which chip held the mileage and then build out from there.

I've not been able to find a schematic, parts diagram or anything at all on these clusters. These appear to be Huntsville ( or at least USA ) produced.

Help!
 

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I have a rebuilt 1987 LeBaron GTS cluster and at least one from a 1988 New Yorker, but that's about it.

My guess would be there is a problem in the power supply section of these clusters. Unless they're broken, the VFDs themselves should be ok. It's getting to the point now that bad capacitors are more and more likely to turn up in these... even the good ones have a finite lifespan. In the completely dead ones, I'd go looking for fried voltage regulators too.

But at this point, it wouldn't be a bad idea to start re-capping these clusters even if they're working. Those capacitors won't last forever.

The problem is, we're not likely to get our hands on schematics for these and a lot of the parts use proprietary Chrysler part numbers. Makes everything harder than it needs to be, and drives me right up the wall.
 

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Discussion Starter #3
How would one go about checking or metering a voltage regulator ? Do they meter the same as a regular transisitor or diode would ?
I beleive there's a regulator with a faily large external aluminum finned heat sink on one of the two boards.
I saw no signs of overheating and no signs of swollen or leaky caps.

Should I be looking for shorted or open caps or just change out what I can ? There are quite a few components on the two large boards that comprise these clusters. Would you have any way to identify the p/n of the chip that contains the mileage ? I may be able to take a working cluster and swap the mileage IC's over to keep the proper mileage with the car.
 

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The earlier mileage storage ICs were in a socket for quick swaps. Later ones were soldered in for tamper-resistance and the depots did the repairs on them for that. There may be printing on the circuit board identifying the chip.
Components and schematics are copyrighted Chrysler information that is available to the authorized radio/cluster repair depots for their reference only. United Radio is the depot in our area. It is not public information (yet), but once in a while something 'secret' shows up on the internet temporarily. It can be quickly taken down, so download it if you see it. GM Delco/Delphi and Ford Motorcraft electronics are the same way.
It helps if you know someone at such a facility. Of course, things this old are no longer supported parts or service-wise, but you may find someone willing to help you if it is within their power and they have an appreciation for old things.
A cap can still have high ESR (leakage) without any external signs. A leaky cap will add load to 12v DC-to-22v DC converters and can damage them. The VFD tubes run around 22 volts at a low current to light them. The life of an electrolytic cap usually a safe ~20 years, but can vary widely depending on its duty or quality, etc.
 

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Discussion Starter #5
Hmmm. United Radio in Syracuse ?
I beleive they do repairs for consumer electronics products. The company I work for sends a/v gear to then for repairs both in and out of warranty. I'll contact them to see if they'll repair the Chrysler instrument clusters of this vintage.
Thanks for the tip.
 

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They do a lot and it's getting difficult to find to find a reasonable electronic repair facility in the 'disposable' electronics society of today. I worked at an AC-Delco radio repair facility here in Rochester for some years and I've been to their facility. UR are good guys.

http://unitedradio.com/automotive/
 
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