[Staowners] [Fwd: Alpine Mk 1 tank gauge]

[George Simpson - Forums]

Ernie - following our correspondence of a few months ago, last week I 
got a complete set of instruments from Mark Chatel and now I'm home 
again, I took the petrol/temp gauge out of the frame. I have a spare AC 
sender so I started as suggested and tested the sender with a 12v supply 
and with a 12v 6W bulb in series  .... good news, the bulb went from 
dull to bright as I raised the float arm.

Then I looked at the petrol gauge. Funnily enough, if I hold the 
instrument upside down (I know - Alpines are not often in the 
position!!!), the gauge slowly goes round to FULL. I then gave the two 
terminals a brief 'jolt' with 12 volts. The needle came off its stop and 
sat on Empty - ah-ha, I thought, a good start. Then I reversed the wires 
to see if anything changed ...... no - the needle just came up to Empty 
again. Being a perverse character, I turned the gauge upside down and 
tried again. The needle still moved to the Empty mark.

Next step, connect them all up. Once connected, the gauge came off its 
stop up to the Empty mark but when I raised the float, the needle moved 
about a millimetre into the range - it was a barely imperceptible 
movement but there was a movement. I then reversed the terminals on the 
gauge but got exactly the same result.

All of this I did before getting the old gauge and sender out of my car 
to be sure everything worked but, as you can see, I have not made a lot 
of progress. The sender is an AC unit looking identical to the one shown 
on p. 144 of the Parts Supply book. It came with a paper tag showing 764 
which might or might not have been some sort of reference at an AutoJumble.

All suggestions are welcome

George
Cognac



Ernie and Doreen Taube wrote:
> Hello George:
> I had to overhaul all my instruments because they had been under water.  So
> here is some quick checks to do.  Remember all the instruments are basically
> volt meters.  Disconnect the wire from the instrument and using a jumper
> wire just activate the gauge and see if you get a needle response. If the
> needle goes to full then the instrument is  working. If it does not move
> then reverse the leads and see if you get the movement.  This little test
> will let you know the polarity and if the gauge is working.  If it does not
> work there is more than likely damage to the windings in the instrument.
> Not worth trying to fix. If this shows good operation then you will have to
> check the sender.  On the fuel tank unit , when you have it out you can
> dismantle the active part of the unit by removing  a couple of screws and
> this separates the main body from the active element. Check the windings
> that forms the rheostat.  In my experience these windings either wear
> through or break, also can arch through leaving a gap. This will make the
> gauge inoperative because you now have an open circuit.  I would check the
> tank unit first because the odds are that is where your problem is. I have
> not been able to make a good fix on these windings. The wire is so fine and
> it is a resistor and when you loose some of the winding it changes the gauge
> readings. But you may have some luck.
> Another note to you , if you do find the gauge defective do not give up, All
> the gauges in the ST 90 and Alpines are the same.  They just have different
> bezels. That is to say the gauge face itself is the same, it is just the
> instrument cluster face that changes.  The only different gauge is the
> Speedo. The 90's have a lower top speed than the Alpines, but can be used in
> pinch.  I hope this info helps you in your efforts
> Best wishes Ernie
>
>
> ----- Original Message ----- 
> From: "George Simpson" <george.simpson at tiscali.fr>
> To: "STAO" <STAOwners at sunbeamtalbot.info>
> Sent: Thursday, July 06, 2006 5:21 AM
> Subject: [Staowners] Tank gauge
>
>
>   
>> Since owning my Alpine, the petrol gauge has never worked. Last weekend,
>> I got round to testing it. First I added a wire from one of the screws
>> holding the sender unit to the tank to a good earth. Then, with a full
>> tank of petrol,  I verified that I had 12v at the gauge, measured
>> between the sender wire coming from the tank and the 'power' wire from
>> ignition.  However, when I connected these last two wires to the two
>> terminals on the back of the gauge .... nothing. As I cannot tell if
>> polarity on these two terminals is important, I swapped the wires over
>> but still nothing.
>>
>> Does anyone have experience with this instrument or know the resistance
>> value the gauge should give? The previous owner gave me a couple of
>> other petrol gauges he had bought in auto jumbles - is it worth trying
>> to take the instrument to pieces and check/change the innards? Is there
>> anything else I can do, apart from changing the gauge (which is a single
>> unit with the temperature gauge). Presumably it is the same instrument
>> as on the S-T 90 so I need to see if anyone has a spare (Pete ???)
>>
>> Thanks
>>
>> George
>> Cognac
>>
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>>
>>
>>
>>     
>
>
>
>   
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