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Re: What have you done with your Series 3?

Posted: Sun Aug 09, 2026 8:14 am
by Neil Bymouth
How do you know that it's an electronic stabiliser by testing the voltage to the temperature sensor?. It could be a bi metallic strip one working properly?

Re: What have you done with your Series 3?

Posted: Sun Aug 09, 2026 8:37 am
by o4dn
The way the metallic strip works is by interrupting the circuit. It shows on a digital voltmeter, the readings fluctuate constantly, whereas an electronic device produces stable readings on the digital voltmeter.

It's actually well described in the page I've linked previously:
the original MG Voltage Stabilizer doesn't actually regulate voltage at all! Instead, it cycles power "on" and "off" to achieve an average voltage (over time) of about 10 Volts. If you take an old-fashioned Voltage Stabilizer apart, you'll find a bimetallic element with a resistance wire wrapped around it (much like an automatic-reset circuit breaker, and not entirely unlike the gauges themselves.) Heat in the resistance wire causes the bimetallic element to bend. The bimetallic element actually bends back and forth quite rapidly, and in turn it rapidly opens and closes a set of contact points. Thus, it switches between a nominal supply voltage of about 12 Volts and a disconnected state (i.e. zero volts!) That suits old-fashioned, single-coil MGB gauges pretty well because they have a lot of mechanical dampening built into them. If your gauges are sufficiently damped, you may not see that their needles constantly wiggling as the Voltage Stabilizer chatters on and off; you'll only perceive the "average" readings they're showing you.
Source: https://www.britishv8.org/Articles/MGB- ... ilizer.htm

Re: What have you done with your Series 3?

Posted: Sun Aug 09, 2026 9:40 am
by Neil Bymouth
Thanks. I missed that. I know I've gor a bi metallic one at present because the gauges are up and down all the time. I've got a spare electronic one to fit when I get around to the dreaded job of pulling the instrument cluster forwards.

Re: What have you done with your Series 3?

Posted: Sun Aug 09, 2026 9:48 am
by o4dn
Neil Bymouth wrote: Sun Aug 09, 2026 9:40 am [...] I've got a spare electronic one to fit when I get around to the dreaded job of pulling the instrument cluster forwards.
Honestly, it's not that dreadful.

Remove the steering wheel (after marking the position on the steering column), unplug the speedo cable from the cluster, and you have enough room for a screwdriver to undo the stabilizer.

While at it, I took the opportunity to replace the light bulbs for the instruments with led replacements (that I had for some time waiting to be fitted).

Re: What have you done with your Series 3?

Posted: Sun Aug 09, 2026 10:42 am
by Neil Bymouth
I had to replace the electronic voltage stabiliser recently becsuse it kept blowing the fuse. I had only a bi metallic one. Howrvet, I managed without removing the steering wheel but the clip on the speedometer cable is broken and it's fiddly getting it to stay when pushing the cluster back. I've got to do it some time to replace the voltage stabiliser and the trip reset cable.
Another job I'm dreading is replacing the dashboard top with the NOS one I bought from Blanchard's.

Re: What have you done with your Series 3?

Posted: Mon Aug 31, 2026 7:24 am
by Carlos Fandango
Spent a day green Laning with Hert and Upper Great Ouse
Great day with Great people

Re: What have you done with your Series 3?

Posted: Mon Aug 31, 2026 12:08 pm
by Neil Bymouth
I had a choice of sorting through my large collection of Whitworth spanners to see what sizes there are, or walking the dog to the pub at lunchtime. I asked him and immediately it was the pub.

Re: What have you done with your Series 3?

Posted: Mon Aug 31, 2026 1:57 pm
by Carlos Fandango
Tomorrow take the spanners to the pub and sort them there :-thumbsup

Re: What have you done with your Series 3?

Posted: Mon Aug 31, 2026 2:41 pm
by Neil Bymouth
Tomorrow I've got to de ivy a shed at the pub so no alcohol as I'll have to drive there.
Next session will be Saturday 5th September.