Overhead console computer source

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tgreese
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Re: Overhead console computer source

Post by tgreese »

The resistor almost certainly burnt because one of the electrolytic capacitors (ecaps) shorted to ground through the resistor. The ecaps are the cylinders with aluminum tops and an X on top. These are the most common failure on old equipment. They can go short or they can blow up or they can bulge before they blow up.

They are polar, and if you wire them backwards they will pop. BTDT.

I have a page about ecaps if you are interested - https://www.nmr.mgh.harvard.edu/~reese/ ... index.html
This is targeted at old vacuum tube equipment that run high voltages, but much of the discussion is relevant to ecaps in general, including the low voltage types in this board.

The resistor pointed out above is a SMD (surface mount device). Not easy to replace unless you have experience with them. You could replace with an axial resistor as reasonably suggested above, by soldering across where the trace goes. If the traces are not damaged, you could instead solder in a new SMD resistor in the same place. Either type of resistor is easy to get. All well covered above.

If you want to replace a SMD, there are You Tube videos that show you how. Clean the circuit board pads and tin them, apply a little liquid flux, hold the device on the pads with tweezers, and touch the tip of the iron to one side of the device. It will be stuck and you can solder the other side with a little more solder wire, then go back to the first side and finish up with a touch more solder. Easy if your vision is good and your hands don't shake.

Two issues that have not been mentioned -

I expect that burnt resistor won't have any readable markings now. You could guess that it's the same as the other two resistors that are nearby, and get in there with a magnifying glass to read them. Or someone with an undamaged board could read the value on the resistor (above poster?)

I would replace all the electrolytic capacitors on that board (five of them). If one is done, they are all done (looking back this has been mentioned). Easy and cheap if you can solder at all. Look on YouTube for videos about desoldering.

Possible there is something else wrong with it. Probably not. You have to fix these issues before you can test it any further.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

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Johnzi10
Posts: 256
Joined: Wed Nov 25, 2020 9:43 pm
Location: Northern Kentucky

Re: Overhead console computer source

Post by Johnzi10 »

This might be above my pay grade! Currently working on soundproofing roof, reinforcing luggage rack and clear coat roof while rack is off. Can a vendor be recommended?
2020 Cherokee Limited v6. Wife’s Jeep
2002 Grand Cherokee Laredo Daughters Jeep
1998 XJ Cherokee “the Ghost”
1989 Grand Wagoneer my Covid mental health medicine
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tgreese
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Re: Overhead console computer source

Post by tgreese »

Vendor for?
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
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Dusty
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Re: Overhead console computer source

Post by Dusty »

This is the exact same board used in the 86-96 Cherokee XJ's.
Most if not all have been cooked from being up in the hot roof of the Jeep.
Here is a how to on repairing it:

https://www.cherokeeforum.com/f46/malco ... ost3563716
If God is your co-pilot, you need to switch seats!

Topic author
Johnzi10
Posts: 256
Joined: Wed Nov 25, 2020 9:43 pm
Location: Northern Kentucky

Re: Overhead console computer source

Post by Johnzi10 »

My fine motor skills are not up to this repair. 89 Wagoneer mentioned something in a previous post, but have had no luck. I’m looking to pay someone to fix it.
2020 Cherokee Limited v6. Wife’s Jeep
2002 Grand Cherokee Laredo Daughters Jeep
1998 XJ Cherokee “the Ghost”
1989 Grand Wagoneer my Covid mental health medicine
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tgreese
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Re: Overhead console computer source

Post by tgreese »

I don't have anyone to recommend. I could do it, but I'm not a repair service. Maybe someone else reading the thread will recommend someone.

You might be able to search and find the eBay vendor that 89 Wagoneer refers to. You could also start a new post with a descriptive title in as many Jeep forums as you can get into. Sp. I would ask here and at IFSJA and all the Cherokee or Grand Cherokee forums. Ask about a source for a repaired board in exchange or somewhere that will repair your board.

You could also try local auto electric shops. They maight not do it, but they might have connections to a place that has the boards available for exchange.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

Topic author
Johnzi10
Posts: 256
Joined: Wed Nov 25, 2020 9:43 pm
Location: Northern Kentucky

Re: Overhead console computer source

Post by Johnzi10 »

Thanks for the leads!
2020 Cherokee Limited v6. Wife’s Jeep
2002 Grand Cherokee Laredo Daughters Jeep
1998 XJ Cherokee “the Ghost”
1989 Grand Wagoneer my Covid mental health medicine

Topic author
Johnzi10
Posts: 256
Joined: Wed Nov 25, 2020 9:43 pm
Location: Northern Kentucky

Re: Overhead console computer source

Post by Johnzi10 »

Found an electronics repair shop, $20.00 to check it out, should have a repair quote in a couple of days
2020 Cherokee Limited v6. Wife’s Jeep
2002 Grand Cherokee Laredo Daughters Jeep
1998 XJ Cherokee “the Ghost”
1989 Grand Wagoneer my Covid mental health medicine
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tgreese
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Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Overhead console computer source

Post by tgreese »

Just a comment. Reading the repair thread linked by Rusty above, I realize those SMDs are not resistors, but ceramic chip capacitors. Usually a ceramic chip capacitor will last forever, but the one that is charred did not. If they short, the become charred like the one on the OP's board.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

candymancan
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Joined: Tue Mar 22, 2016 11:32 pm

Re: Overhead console computer source

Post by candymancan »

I could replace all the caps including the quartz crystal in th3 silver tower looking thing. I did this on mine and ones i sold on ebay that i got from junkyards. I could probsbly do th3 resistor as well but i would do it with an inline resistor as its too difficult for me to solder tiny rectangle resistors to the board. Id just follow the trace it runs from and to and just solder the resistor from their starting to end point. By passing the actual trace

The issue is i dont know that type of resistor it needs. If we knew the type.

Then all it is is simoly ordering it and soldiering it in. Would probly take me 15 min.

I have all the caps actually . I have a baggy with 10 or so extras i ordered
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
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tgreese
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Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Overhead console computer source

Post by tgreese »

I was wrong - it's not a resistor. It's a ceramic chip capacitor. It would be ok to read the one next to it that's not burnt and use a replacement of the same value.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: Overhead console computer source

Post by candymancan »

Oh i thought it was a resister my bad too then
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
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