MX83 speedo issues

**petergoudie** · 30-01-2011, 06:05 PM

My 91 Grande does all of the above however the water temp gauge seems to have an intermittent fault also and occasionally dies in unison with the speedo.

I have checked the electronic speedo sensor and it was working fine.

Is the speedo board exactly behind the speedo cluster?

How do you remove it?

Thanks

**WA_TRD_83** · 30-01-2011, 06:30 PM

I had this response on the Cressida forums - but I just havent gotten around to pulling apart the dash yet

Originally Posted by JasonP

the problem is more than likely on the speedo driver board. If you pull apart the cluster, it probably looks like this:

Clean the tracks off, repair any that look broken, replace the capacitors and it should be good.

... which is pretty much what Nilezy said

I'm not sure how to clean and repair the tracks, so I was just going to replace mine with one from another car that works and looks in better condition.

Damo

**Nilezy** · 31-01-2011, 01:34 AM

WA_TRD_83,

Best way to clean the tracks and repair is to desolder the PCB board from the speedo unit (The four gold looking screws in the middle of the board come out and there are four solder points next to those four screws that need to be desoldered and the little electric motor needs to be unscrewed, two screws for that, then take the PCB off the speedo unit)

You will need to buy a bottle of Isopropyl Alcohol, which is almost pure alcohol. You need alcohol without additives to clean the PCB on both sides properly to remove the electrolyte using an old, clean toothbrush.
Desoldering the electroyltic capacitors should also be done before the board washing so you don't get more electrolyte on the board after each wash. Remember the values and polarities of each capacitor as you remove them so you can replace them with new capacitors of the same value and the same polarity after you have finished washing the board.
Wash the board in the Isopropyl 3-4 times and let it thoroughly dry on the last wash. Then you can clean up the tracks. If there is a track that has a cut or gap you can join the start and the end point with a peice of wire to re-connect those points.

Then all you need to do is put the electric motor back and solder the four points on the board back to the speedo unit and it should work fine again.

If you want, I can do this for you if you send me the speedo.........

If you are not going to use that damaged one and it was still working, wana sell it to me?

Cheers,
Nilezy

**petergoudie** · 31-01-2011, 09:23 AM

Is the electric motor to silver can marked YAM-17 Seiko Epson in the photo or the can between the four screws? Thanks

**Nilezy** · 31-01-2011, 11:39 AM

Sorry, should have added the pic:

The blue arrows are the four solder joints that need to be desoldered. Best to use desoldering braid to remove any solder as it will be difficult to apply heat to all four points at the same time to lift the board off the speedo unit. BE careful that you have the four pins desoldered before pulling the board up as there are very fine wires attached to them for the speed needle motor and they can break very easily. The pins are also only pressed into plastic so can move when you pull the board up to remove it. If the four points have been desoldered fully, the board will lift away easily. If it doesn't, you still have solder still attached on one of the four points.

The red arrows are the motor YAM-17 and the four gold screws that need to be removed to lift the PC board away from the speedo unit. The motor has two small screws holding the motor onto the speedo unit which you can see after you remove the main PC board from the speedo unit.

The green arrow is pointing to the flat cable for the motor. You have to be careful when taking the main PC board off the main unit as this cable is attached to the motor, hence why the motor also has to come off and the flat cable is fragile.

Hope that helps.