Cluster regulator?

[Cookie77]

I have looked on wiki but a little confused on the checking of my instrument cluster?

When I look at my cluster from the rear I can see the regulator with 3 prongs and fixed with a screw at the bottom.
When I test it I am getting 12v from the 1 on the left, the centre pin go's nowhere (not connected to anything)
And the right hand pin I am getting 10.5v

Is this correct or backwards???

[Oldiebut goodie]

You read HERE bit on changing it?
That should be correct.

Centre pin is negative.

Now it depends upon whether you are looking at an original or a replacement. If you have a replacement it may be 'upside down' with the tab away from the fixing point. Are you looking at it in the same orientation as in the figure? What are the markings on the regulator?

[Cookie77]

The codes on the regulator are. Ka78-10a

I am looking from the rear of the clocks so I am looking directly at the ribbon and the regulator

My centre pin has no where to fix to ?

On the tab where it fixs on to the clocks there is also a collar/washer fixed to it? Not sure if this goes in contact with the ribbon or faces out?
It faces out at the moment and as I said before looking from the back I am getting 12v from the left pin and 10.5 from the one on the right (looking directly at it from the back of the clocks)

[Oldiebut goodie]

The tab is the same as the centre pin.

If the tab is raised from the mounting point, by a washer, with the writing on the regulator face down to the ribbon that is correct for a replacement standard 7810. The A suffix denotes that the voltage tolerance is 2% rather than the standard 7810 which is 4% voltage tolerance.
It sounds to me that it is working perfectly normally.

What is the problem with it?

[Cookie77]

The fuel gauge and temp gauge seem to read wrong ( higher than they should be)

When I first looked at the regulator the earth screw fixing was very loose and loose on the 2 prong fittings so I removed it and could not remember witch way around it went???

I have since found another regulator in the dash so I think it has had a problem in the past?

At the moment the wrighting on the reg is facing out and the readings I am getting are as above in last post

So does it need to go the other way around??

[Oldiebut goodie]

With the KA7810A the writing should be face down with a spacer under the tab.
The left leg should read 12v+ measured between the centre leg or tab and the left leg.
The right leg should read 10.4v -ish between the centre leg and the right leg.
This is with looking at the regulator with the tab at the bottom and outmost with a spacer underneath.
Ideally there should be an aluminium heatsink added to the tab when using the standard 7810 upside down as it hasn't the same contact to the mounting point.

Is there any sign of the wiring having been changed/tampered with as it seems odd that you are getting the correct readings in the right positions with the the regulator the wrong way round.

Remember to take a photo before you disassemble - saves a lot of head scratching later!

[bigherb]

It sounds like you have an early dash where the regulator centre pin is not connected. From your description it is working correctly the right hand pin is the output and should be between 9.5V and 10.5V.
This is the early regulator.

[Oldiebut goodie]

But the KA7810A has the output on pin 3 and the input on pin 1 (checked the datasheet) - that is what is confusing!

[bigherb]

But the KA7810A has the output on pin 3 and the input on pin 1 (checked the datasheet) - that is what is confusing!

Without seeing which way his is mounted cant tell, but as long as the 10v output is to the right it's working. I used a L78S10CV the last time I did one and that has to be reverse mounted as well.

[Cookie77]

It sounds like you have an early dash where the regulator centre pin is not connected. From your description it is working correctly the right hand pin is the output and should be between 9.5V and 10.5V.
This is the early regulator.

Yes this looks the same as mine

but the regulator does look different and as i said the collar/washer on the tab is facing out at the moment, but will re-check the voltage i am sure i had it so the 10.5 was on the right hand pin

will re-check tonight

Thanks for the help

[Cookie77]

Yes as I have it fitted now I am getting the readings from the pins as the picture above. So I take it this if fine and working correctly

[Oldiebut goodie]

Yep - we got there in the end.

[Cookie77]

Thanks for all the help