Faulty GTA Speedo Circuit Board

by **AndyClark** » Sat Dec 11, 2004 12:25 pm

I have a 1990 GTA atmo. Does anyone know if the circuit board can be repaired or if any company can reproduce one?

The speedo needle would on start up stick at a very high indicated speed. After a few miles, it would work its way down gradually. It would then work normally only at speeds above 20 mph i.e would read 20mph when stationary.

Any help would be appreciated.

by **David Gentleman** » Sat Dec 11, 2004 2:04 pm

Hi Andy

Check the search facility on the forum and search for speedo. You will then realise no one has the faintest clue why the speedos go wrong all the time, and everything has been tried. It seems the only option is to replace the unit, if you can get one!

by **rupert** » Sat Dec 11, 2004 2:34 pm

Although there is a well known repair to the fuse board... one component has to be replaced and this can fix it... I will check to find out which one. After all, if you've gone to the trouble of undoing the binnacle you might as well get the soldering iron out and change the bit.

by **simontaylor** » Sat Dec 11, 2004 7:15 pm

My car had a new speedo/rev counter panel fitted in 2003, the receipt say £285. When I got the car it only had 270 miles on the clock this Easter, now has 2,500. It too has been playing up. The speedo needle has trouble keeping up with the speed of the car under acceleration, it also has a fit of jumping all over the place sometimes. Just last weekend, upon starting the car, the speedo accelerated upto 160 mph within 0.5 of a sec and I was still stationary in the garage. Then 10 minutes later, I had a problem with a STOP light coming on and both the engine fans not working , then they did start working another 5 mins later. Oh hell, now I know I've got some of the Alpine electrical gremlins on board. I feel it is an intermitant earthing fault and I will be cleaning/reseating all the earth connectors over the winter. As DG says, do a search, you will see that others have tried allsorts of fixes and some have done the trick.
Good Luck!

by **David Gentleman** » Sat Dec 11, 2004 11:44 pm

Just a thought today, but i wonder if it would help if a new power and earth feed from the battery was made for the speedo array. My car has the same problem of a dodgy speedo (reads 0 constantly), but if If both of my windows are closed and I push both electric window buttons up (to cause a power drain), by speedo slowly rises to 40mph, when I let go it drops to 0 again. Its definately a power/earth fault methinks....

I might not get round to fixing this as the fault doesnt bother me that much, and every time you pull the dash apart you just incur more rattles on an 18 year old car!, but im sure somebody will give it a go!

by **rupert** » Mon Dec 13, 2004 6:58 pm

I've been searching through old CAR 'le Journals' to find the article about these circuit boards but can't find it anywhere. I remember the the faulty component was the gray cylindrical bit near the top of the board, best take it to a component seller and get them to work out what it is and supply a replacement.
Thats what I'm going to try, unless anyone else out there remembers the article and can find it?

by **stephendell** » Tue Dec 14, 2004 1:58 pm

Diode at the top of the board or capacitor at the very bottom. The capacitor is easily damaged and on occasion has even been missing. Both available from Maplin or similar for a few pence. Easily fitted if you are handy with the soldering iron.

Worth changing both before spending $$ elsewhere (sorry no pound sign on Australian keyboards!!)

The drive for the speedo needle also wears quickly and can cause the needle to stick or flick. You can change this if you have a spare without changing the whole cluster.

Basically its all just rubbish. If you have the cash buy a nice set of STACK or similar instruments and bin all the GTA stuff. Demon T. have a nice new cluster in the 2005 motorsport catalogue with a rev counter needle that changes colour at programmable rev intervals. Very smart, not cheap though!

David can you get it any cheaper :wink:

by **peterg** » Tue Dec 14, 2004 3:51 pm

My rev counter and speedo were both wayward when I got my car. When I took the pod out the speedo wire was frayed.....I reconnected it and cleaned up the other connectors and wires and hey presto no more problem!

by **pgoldsmith** » Wed Dec 15, 2004 8:52 am

Speedo faulty? Subject close to my heart...

Ever since owning my GTA (2 and a bit years) mine has played up.
I have posted a couple of comments regarding it just not working but never suffered misreadings. However all I can say is that it would be worth removing the facade and disconnecting the main square connector block on located just off on the left of the speedo dial and spraying the contacts with switch cleaner. Also do the same on the two connectors on the rhs of the rev counter. This worked for me for and on the odd occassion when it decides to play up again I simply take the lhs air vent out and wiggle the big square connector again and it seems to spring back into life.

I believe as everyone else agrees its to do with bad earthing or just plain bad wiring design.

(I did also decide to remove both earthing straps to the chassis but that made no difference at all)

good luck.

by **LiamMcShane** » Wed Dec 15, 2004 9:13 am

My '88 Turbo speedo sometimes cuts out when I'm driving, but I also noticed sometimes it spins right up to 150mph when I'm stationary. Normally a slap on top of the dash corrects it!!

by **Alpineandy** » Wed Dec 15, 2004 1:30 pm

LiamMcShane wrote:My '88 Turbo speedo sometimes cuts out when I'm driving, but I also noticed sometimes it spins right up to 150mph when I'm stationary. Normally a slap on top of the dash corrects it!!

This is getting too technical for me now....

by **mitchella** » Wed Dec 15, 2004 1:59 pm

Mine does the 150mph thing and the 0mph thing fairly frequently but never in the middle of a journey. If it's like that immediately after starting, it will stay in whatever state it's in until the ignition feed is cut. I have found that dipping the clutch and switching the ignition off and on again whilst moving will usually clear the fault. I tend not to care about the 0mph but having the car's mileage rack up at the rate of 2.5miles a minute tends to sting me into action when it does the 150mph business.

by **peterg** » Wed Dec 15, 2004 2:20 pm

When my instruments malfunction I sometimes find that talking to them really softly then suddenly suprising them by shouting and slamming the drivers side door gets them working :lol: