Nuffield 4/65 instrument failures

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DAL PZ
Posts: 113
Joined: Mon Apr 09, 2018 10:39 am

Nuffield 4/65 instrument failures

Post by DAL PZ »

Doing some baling with the 4/65 last week when simultaneously the battery condition/ammeter gage & the fuel gage stopped working. As both went together am I right to suspect the voltage stabilizer? Is there another explanation of this B.O.G.O.F event.?
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Nowtnew
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Re: Nuffield 4/65 instrument failures

Post by Nowtnew »

No
The voltage stabiliser only drives the fuel gauge and temperature gauge.
If the Voltmeter has stopped reading it means you have lost the supply, which means everything except the oil pressure gauge will fail

Have you any other 'ignition' controlled systems, eg indicators? This might help you diagnose the fault.
What about the charge warning lamp?

Regards
DAL PZ
Posts: 113
Joined: Mon Apr 09, 2018 10:39 am

Re: Nuffield 4/65 instrument failures

Post by DAL PZ »

Thanks Notnew.
To be honest I actually don't know if the Temp gouge is working or not as I was away & someone else was using it who only reported the voltmeter & fuel gouge as failing & having put it away in store had removed the dash panel as there was some condensation as well. By the time I got to it all that I could verify without starting it & getting it out was that the fuel gage wasn't working.
The unit itself was New old stock Leyland several years ago & I transferred the original Nuffield voltmeter, oil pressure fuel & temp gages to it. The fuel tank sensor, temp sensor & the loom were also renewed & its all worked fine since the only "problems" being with the voltmeter reading low & the control box sticking.
Its still negative earth & a dynamo There are no other ignition controlled circuits its not fitted with indicators.
There is no charge warning light fitted either just redundant indicator warnings L&R & a air filter warning (dry type only) Main beam is the only functional warning light on the display & that's working as are the dash lights & in establishing that just now I have discovered that the voltmeter actually does respond when the ignition is on with all the lights switched on showing the discharge but not the fuel gage so there is power!
I suppose the place to start is to see if the temp gage works when its started & warms up then look at the fuel gage sender & circuit
Nowtnew
Senior Member
Posts: 297
Joined: Sun Apr 01, 2018 8:49 am
Great Britain

Re: Nuffield 4/65 instrument failures

Post by Nowtnew »

If you do eventually find that the instrument regulator (stabiliser) is faulty, solid state replacements (plug in) were available on ebay, Some were direct fit. About a tenner and far better than the original
You can test it out by connecting the input and output together. This will put full voltage on the instruments. It wont break them but they'll read incorrectly and erratically. I'm assuming you are sufficiently electrically savvy to work out which of the terminals is which.

Good Luck and regards
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