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MGB solid state voltage stabilizer question

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wicklowwanderer Avatar
wicklowwanderer Silver Member David Steverson
Marietta, GA, USA   USA
My fuel and water temperature gauges have stopped working. I have a fairly new solid state voltage stabilizer on the car. When the ignition switch is on, I have power to the green wires ("B" post), but no power to the light-green green ("I" post). All the stabilizer does is take 12 volts and reduce to 10 (or something), right? I should have power on the "I" post, so could these new new solid state units go bad in just a few months? Am I missing something here?....

Thanks, David

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Steven 67GT Avatar
Steven 67GT Steven Rechter
Imperial Beach, CA, USA   USA
You may be missing a good ground connection.

The voltage regulator is a three wire device; input, output and ground.

Clean up your ground connection and it will probably function again.

ddubois Avatar
ddubois Gold Member Dave DuBois
Bremerton, WA, USA   USA
Quote: The voltage regulator is a three wire device; input, output and ground.

That is not entirely correct. The stabilizer does have three spade lugs on it but it gets its ground through the mounting screw that holds the stabilizer to the bulkhead. Make sure that you have a clean surface, completely free of any paint or primer on the both the bulkhead and the bottom of the stabilizer and insure that the mounting screw is tight. Cheers,



Dave DuBois
1953 MGTD
1966 MGB
http://homepages.donobi.net/sufuelpumps/


Member Services:
SU fuel pump restoration and conversion to solid state. Information and technical articles on SU fuel pumps.
jjonns74 Avatar
jjonns74 Gold Member John Dailey
Indianapolis, IN, USA   USA
1974 MG MGB "Athena"
1974 MG MGB "Apollo"
You could also temporarily connect a jumper wire, with alligator clips, from a known good Ground point to the VS metal case.

If output on "I" terminal is now present, you know the physical Ground connection is insufficient.

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wicklowwanderer Avatar
wicklowwanderer Silver Member David Steverson
Marietta, GA, USA   USA
I tried John's suggestion. With the stabilizer just hanging and green wires attached, I have power to "I". Now with a test light on "I", as soon as I touched a ground to the metal case, "I" lost power. This is one of those modern solid state type stabilizers, it must have become "intermediate" state somehow. I'll order another one.

Thank you all for your help, David

jjonns74 Avatar
jjonns74 Gold Member John Dailey
Indianapolis, IN, USA   USA
1974 MG MGB "Athena"
1974 MG MGB "Apollo"
I just replaced my OE VS with a Solid State version.

Well, Almost replaced: mine is hanging by G and LG/G wires with a jumper wire from case to Ground (so I Know this works).
I'll get around to properly mounting it one day soon.


I also see an alternate 10v source:

http://www.ebay.com/itm/NTE-NTE1953-IC-Vltg-Reg-Pos-10V-1A-Low-Dropout-/200404969310#shpCntId

Looks like the center pin (Gnd) could be snipped off > G wire to Input, LG/G wire to Output > mounting screw to good Gnd = very basic install.
I've seen guidance on gutting the OE case, & installing the Vltg Reg inside the case (for a better appearance).


John

Wachtmans Avatar
Wachtmans Wouter Strodijk
OVERVEEN, Noord Holland, Netherlands   NLD
1974 MG MGB "The Bee"
1974 MG MGB "The Bee"
1974 MG MGB MkIII "The Bee"
I had installed a new solid state voltage stabilizer unit as well. New solid state (Chinese) units ar crap; temperature and gas level were still far out (too high) as measurement revealed the output voltage was around 12 volts as it should be 10 volts. You can buy loose, reliable voltage stabilizers (e.g. Ebay) and mount/solder them inside the old housing. I did and it works very well now.


Attachments:
Voltage regulator 10 volts.jpg    3.4 KB
Voltage regulator 10 volts.jpg

Chriswatts Avatar
Chriswatts Silver Member Chris Watts
WISBECH, Cambridgeshire, UK   GBR
1975 MG MGB "JMMY"
So would I have one of these on my B 1974/5 and is it something I should change?

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ozieagle Avatar
ozieagle Gold Member Herb Adler
Geelong Victoria, Australia   AUS
1958 Wolseley 1500 "Wooly"
1966 MG MGB "Bl**dy B"
In reply to # 3718145 by Chriswatts So would I have one of these on my B 1974/5 and is it something I should change?

OEM was a mechanical device, not solid state.

There is no need to replace it, if the gauges are working correctly.

Herb



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MGB567 Avatar
MGB567 Gold Member Barrie Braxton
Sunshine Coast, Queensland, Australia   AUS
1966 MG MGB MkI "Money Guzzler"
1979 MG MGB GT V8 Conversion "Darkside"
"So would I have one of these on my B 1974/5 and is it something I should change"

Yes you have one (provided your gauges are OEM Smiths). As Herb says if they work no need to change. The OEM are NLA (although some like to repair). If it's not evident on your firewall when you look it could be like mine on the '79 and hidden up behind the wiper motor.



Convertible: CKD 11/66 first registered 8/5/67. Owned since 3/77. 90% original sheet metal. 18GB +40 balanced with almost all new internals. Peter Burgess big valve fast road head. Piper 285. Fidanza FW. Basil's followers and pushrods. TR7clutch. TT exhaust. ARP everywhere. 123 ign. Needham 4synchro c/r box.. Stock rebuilt/replaced suspension. Superpro bushes. New brakes all round including all pipes in SS flex. Interior redone. CAMS approved roll bar and side bars. Lots more. Hybrid of o/e and show/fast road car. Not for sale - it's my toy!

GT: UK car built/sold December '78. Stripped back to bare shell (with extensive bodywork to come). Powered by 'worked' Rover 5 litre V8 (ex TVR Chimera) with efi. T5 box. FC IFS. CCE rear attached to Salisbury axle with Quaife. And a whole lot more to yet to come. Stealth is the word.



Edited 1 time(s). Last edit at 2018-04-16 07:17 PM by MGB567.

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