1988-1989 Digital Dash repair service

This being the premiere Jaguar forum i thought i would ask the entire XJ40 group which, if any, are the premiere repair facilities for having work done on your digital dash? I have heard that the digital clusters can have problems with bad cold solder joints and i want to know who is the best in repairing them. I don’t want to go through a nightmare by sending a unit off to someone who is NOT the best at repairing these clusters. Also, please let me know if there is any other issues with these clusters besides the solder cracking. If i buy one of these cars and the cluster has issues from the start, i would like to have a heads up as to what the probable cause could be. Thank you.

Repairing a cold solder joint is fairly straight forward, the pain is in removing the items. From memory there is a fairly heavy unit that hangs off the dash panel and this stresses the joints. Its been a long time since I had my ‘40’s but there will be information in the archives, accessed via the spy glass top right of the page.

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Kenneth. I had mine done by BBA Reman. Phone 1.866.573 0266.All the info you need is on their site. Excellent job done.

Thank you for your high recommendation. I will definitely call them and have them do any work on a broken digital dash that i may have. Can you explain what was wrong with your unit before you sent it to them? Do you have to worry about the odometer reading staying correct. Any more detailed information would be appreciated.

Kenneth.Mine had nothing working .The milage will be the same if you have it repaired as opposed to exchanged.

Mileage is not stored in the dash module. It is recorded in the car’s computer so even a replacement part would display correct mileage.

Repair is not that difficult, take out the digi-dash, dissemble and find the main power supply to the digi-dash and re soldier, from memory it is the near the largest connector. Mileage is stored in the dash.

Ive gotten conflicting information on this. Some say the mileage is stored in the car’s ECU computer so any dash replacement will not affect mileage. And i’ve gotten other responses that say the large black box on the back of the dash cluster holds the mileage and if you swap a cluster out with another unit, your mileage will be that of the new cluster. Which one is right? ARG!!!

i just checked their website and it only makes known of the 1989 clusters. Do they not do the 1988’s?? Is there a difference between the 1988 and 1989 digital clusters?

I am sure someone on the forum will have a more qualified answer,but in my opinion there was only 1 digital dash in 88/89

What are the major problems with these digital dashes that tell you the soldering joints are bad? From the research i’ve done, it seems that the gauges portion of the dash will just go dark. Or the dash won’t work at all? I don’t own one yet so i’m not sure what are the tell tale signs of one going bad so that i can send it out to BBA Reman.

if you swap the cluster for another it will display the mileage of the new cluster I have been there done that

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and to go even further if you have an 87/88 XJ40 built before June 88 or so the washer jets on the scuttle are different, and some of the circuit boards in the digi dash are slightly different as well but they should be interchangeable.

Not sure what the washer jets on the scuttle are but basically it sounds like the best course of action is to just have your existing unit repaired NOT replaced by another unit and there will be no confusion. Thank you for so much educating me on this topic.

Ken I am not good at electrical problems,I just took it out and put in the mail.The forum always talks of solder joints becoming faulty so when mine gave up after 15 years I sent to the experts.

I appreciate your concern for getting a professional involved, but IMHO learning to re-flow solder joints on an XJ40 is almost a rite of passage on these old heaps!

Tons of connections, relays, fuse boxes digi-dashes et al need the medication sooner or later!!

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I did the dash in my 89 the VCM monitor not working etc,
Not sure what has failed with yours if nothing works, its a power issue and the POWER BOARD is probably 100percent the cause.

Dash binnacle Comes out with only 4 screws underside of the unit 2 on each side the lights -emergency flasher toggles etc and cruise come out with it too…
Extend steering wheel full out position
May have to remove the wheel… only one center nut… no puller required… careful with airbags on latter models (none are on my 1989)
unplug about 4 connectors from dash binnacle-- no worries as they are all color coded and you cant misfit them

May have been some screws for inside access but I think it-the back of the instrument binnacle just pry-snap-releases off and exposes all the circuit boards…
About electronics:
Most cold solder joints occur due to stress fatigue from heavy large parts, could be large capacitors or any transformer and many cold joints are caused by heat cold cycling stress of power devices like large resistors large semiconductors and any transformers. Soldered connections are not that strong. Using magnifying eyeglasses (I used a small 20x stereo microscope) look for POWER board with large parts, on 1989 model it was one smaller board with transformer large caps large power resistors etc.Yes that board had many stress and heat failures some easily seen with naked eye.
Look at wire PLUGS connector headers soldered on the printed circuit boards again particularly the POWER board this board is most likely culprit but if you can check some others good.
You may want to check all the binnacle bulbs for continuity or swap em all out.
Solder 30 watt max for a pencil iron some nice resin core solder 63% tin 47% lead known as eutetic solder though 60/40 solder OK too should all be resin core flux.
Make sure your IRON tip is clean and silvery and well wetted with solder will help reduce the time the tip is on the parts solder pad. If the solder doesn’t melt on the PC board in say 10 seconds ish remove and try another joint. Don’t heat any area too long though for a large cap or transformer you may have to. Putting a small blob of fresh solder on the tip and then touching the tip to the PC board will hasten the remelt time and help with larger parts solder pads.

If unsure on the POWER board which ones have cold joints and some cold joints are barely visible hairline cracks. To hell with them solder them all there are not that many on the POWER board. Most of the other boards in the 89 with digital dash were digital boards carrying low current, low voltage and therefore low power and low heat and did not need any soldering.
Now you are expert
Good luck
PS one of those jointed table clamp lamps with large magnifying lens and built in light could serve you well.
And don’t poke any circuit parts with fingers as static electricity can cause semiconductor failures

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