Printed Circuit Board Instrument Cluster


(Greg) #1

So my circuit board is in pretty bad shape, I’ve tried to salvage it, but I think I need a new one.

Is there a source for new ones still somewhere out there? Or decent used ones? Part# is DAC3152.

Thanks.

1988 Jaguar XJS


(Robert King) #2

White Allen Jaguar shows available, $50.85


(Greg) #3

Ha, I guess I could try another. But I’ve already checked two Jag dealers who’s website claimed to have them, but when I phoned, they don’t really.

Looks like I’ll have to do my best to salvage my own. Lots of copper tape, and a few wire connectors.


(Robert King) #4

Or maybe a used one; my ‘88 had a broken trace at the tach illumination socket, and I was able to bridge it with solder. Hopefully won’t have to disturb it again.


(Stephen J. Niznik) #5

I have five or six. If interested contact me off list. All were working when cars went to storage.

Stephen


(Ed Sowell) #6

If you’re talking about the flex instrument cluster circuit, I don’t believe they have been available new for a long time. Moreover, you’ll have a hard time finding a decent used one. Typically, the conduction paths become delaminated, especially along the top and where the connectors plug in.


(Greg) #7

yes, that’s what i’m talking about. Hmmm, that’s too bad. I’m hoping to at least make sure the speedometer, tachometer, battery indicator and fuel level indicators work, as I’ll be adding my own water temp and oil pressure gauges.

But was also hoping to eventually restore the vehicle to original, so would be nice to have the full instrument cluster working. You would think in today’s day and age, someone could print one up.


(Jimandhelen) #8

The flexible printed circuit doesn’t normally fail unless repeatedly flexed. Repair is best done with loops of tinned (like a question mark with the circle going under the fixing screws) copper wire or copper foil. The wire or copper foil needs to be tinned first, then quickly soldered to the flexible circuit. Soldering flux can help. Allow to cool if it doesn’t work first time.

Jim Brighton UK
XJSC 1984 3.6 manual


(Greg) #9

thanks, I’ll look into that if I have to. My problem is there was quite a bit of corrosion on flex bits around oil pressure gauge, and many of the copper bits where the connectors push in were cracked and brittle. I bought some copper foil tape, but it doesn’t stick very well. I thought you couldn’t apply solder or it would melt the plastic?


(Jimandhelen) #10

Flexible circuits are made of a higher temperature melting point plastic
& hopefully Jaguar obeyed! Mylar melts at 254C about the same
temperature as a soldering iron, so you have to be quick. The oil
pressure gauge seems easy enough to fix with wire or foil loops or you
may be able to replace that part of the track with insulated wire
bypasses. None of the tracks carry much current, even the lighting
bulbs are low power. The area round the connector is more tricky, can
you manage a photo?

You could try https://simplyperformance.com they have in the past helped
me with spares. They are based near me in the UK & it shouldn’t be
costly to post to you.

Best regards

Jim Brighton UK
XJSC 1984 3.6 manual


(Andrew Waugh) #11

If you’re in doubt as to the melting point of a flex pcb, get some Kapton tape, and stabilize the back of the area you’re trying to fix.


(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #12

Might it be possible to replace that flexible circuit entirely? I’m thinking perhaps some sort of homemade miniature wiring harness actually made of wires. The connectors would be the tricky part, but perhaps the thing to do with some of them would be to simply dyke off the original connectors on the Jaguar dashboard harness and splice on some generic connectors. You’d still need to connect to instruments, indicator lights and illumination lights, but perhaps each can be managed? One possibility might be little miniature flexible printed circuits at each one. The end result might look like a rat’s nest behind the dash, but as long as all the connections are made it should work OK.

I’m just thinking about how to proceed once it is no longer feasible to find replacements. Perhaps we’re not there yet, but eventually it will happen.


(Greg) #13

Ha, that’s taken from your book, right? Yeah, I read that and thought about it, but boy that’s a big job.

With 3D printers and now electrical printers, isn’t there some way to print a new circuit? Could we send an original to someone and have them print out a dozen or so copies at a group rate? just thinking out loud…


(scrimbo) #14

wire it… what else can you do on a cold winters nite !


(Richard Dowling, 1979 XJ-S HE+5sp coupe, 1989 XJ-SC, 2003 XJ8 3.5L) #15

We buy lots of circuit boards from China. Very cheap and very good.
Never bought a flexible one as big as the XJ-S needs.
My guess is we would pay US$20 each in lots of 10.

Naturally somebody has to do the artwork for this board and that is about 5 hours work to measure up an existing one and produce the file.
Not in any rush to do that.

The big drawback is the method of using bare copper contacts to mate with the existing plugs. Still, plenty of those boards still working after 40 years or more, I guess if not disturbed too often it will last a while.


(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #16

I suppose we are all aware that there are at least two different versions of that flexible circuit? The later one has several circuits making a wide sweep around something that wasn’t there on the earlier version. I think the later version might work on earlier cars, but the earlier version will not work on later cars.


(Richard Dowling, 1979 XJ-S HE+5sp coupe, 1989 XJ-SC, 2003 XJ8 3.5L) #17

The 1979 coupe originally had a mechanically driven speedo.
After fitting an HE engine and 5 speed manual box I needed an electronically driven speedo. On Ebay I bought a 2nd hand instrument cluster from an HE XJ-S. The different speedos accounts for a need to change the printed circuit board, and maybe at the same time a few other minor changes were made.
Could be early HE cars still had a mechanical speedo, that I do not know.