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MG MGB Technical - Voltage Stabilizer

What is the conventional wisdom on replacing the Voltage Stabilizer for temp/fuel gauge with a modern solid state unit. If so, what, where do I and from whom, Canada or US. How would I wire it up. If 10 volt not available, how about 2 5 volt units. Any joy?

Thanx
Paul
P. E. Landry

Paul,

There's plenty on the voltage stabilizer in the archives. The short of it is that there are reasons not to substitute, but it is certainly something you can do. 10 VDC solid state regulators are available (I have about 30), and the archives explain how it's done. I never replaced mine, but had planned on it, at one time.
Fred Doyen

My feeling is IIABDFI ("If it ain't broke, don't fix it"). Do you have reason to suspect yours is bad?
Rob Edwards

Thanx for your prompt responses, Fred and Rob. The fuel gauge shows overfull all the time. I changed the sending unit and everything worked fine for a couple of months but not anymore. I looked up the problem in the archives but couldn't find any answers. Can you point me in the right direction?? I can replace the existing but thought I could do an end run and modernize!!

Thanx again for your help.

Paul
P. E. Landry

I don't know about other vendors, but the MOSS Voltage stabilizer, while looking original, has solid state innards.

Pretty easy and inexpensive to make one. Dave Dubois has plans. I belive they are in the archives.

Dave should be able to give you some advice on if that is the problem. He is super with guages and fuel pumps.
Bruce Cunha

You don't say what year car you have, but I *think* on most years the the fuel gauge and the temp gauge both run off the stabiliser, so if the stabiliser is wonky both gauges will misbehave.

The stabiliser works by switching 12v on and off to generate a squarewave that has an average voltage of about 10v. (The technical term is "pulse-width modulation" http://www.embedded.com/story/OEG20010821S0096 ). You can check it with a voltmeter -- you should see alternating 0v and 12v. They typically either work or they don't. Often, when they don't, it's not the device that has failed but rather it's lost its ground. Make sure it has a good ground if it's not switching....

HTH!
Rob Edwards

Paul,

What have you decided? If you're determined to replace the VS with a SS unit, you can have several of my chips (10VDC regulators). Email your address to me, and I'll send them. This assumes you've found the assembly instructions, however.
Fred Doyen

http://shadetreemg.com/voltage_stabil.htm is Wray Lemke's description on how to convert your thermal instrument voltage stabilizer to solid state. Pretty simple.
Bob Muenchausen

Bob:

Thanx for your interest and your information. Unfortunately, Wray's website referred me to Rick Astleys website. This latter has been shutdown and he has ncorporated all his stuff in a book which should be available on the Amazon.com website as we speak. Any other leads on a diagram??

Thanx for your help.

Paul
P. E. Landry

A simple case of lack of grounding of the stabiliser will cause high readings on both fuel and electric temp gauges. The gauges themselves are adjustable, and I have found that changing the sender does cause the gauges to read different to before - significantly - requiring recalibration. Easy to do with the fuel gauge as E and F are easy to achieve, less so with the temp gauge on one hand as there are no definitive limits, but on the other if you are confident that your engine is at a 'normal' temperature then it is easy to adjust the gauge to read in the middle of the 'normal' position.
Paul Hunt 2

Paul,
I have a diagram from a different website where the guy built the solid-state stabilizer using the same chip as above, but slightly different values of resistors. I have the parts to build a couple of them, and plan to do at the slow time during the holidays. If you can wait till Monday, I'll try to bring the website home and post it. Joe
Joe Ullman

Sorry to be a letdown, but the link no longer works. The circuit and article were done by a fellow named W, for Warren, I believe, Haussmann, if anyone cares to search, under Instrument, or Instra Stabilizer.
Joe Ullman

Does anybody have a part number for the Texas Instruments 10vdc Fixed Voltage Regulator mentioned in the MGB VOLTAGE STABILIZER (WRAY LEMKE) web site?

Thaks

Larry
Larry Hallanger

Okay, here's the link that works to see a little different approach:


http://home.comcast.net/~whaussmann/InstrStabilizer/Instr_Stabilizer.htm
Joe Ullman

Thanks for the new link, Joe. Might as well have one that works . . . today at least. It is hard to keep up with links that go dead or are not easy to get to.

BTW, for the time being, you can still get much of Rick Astley's info from the internet archive (tho some photos and graphics will be missing)at http://web.archive.org/web/20050304025645/http://www.mgcars.org.uk/electrical/

You are better off, in the long run to just get Rick's new book on MGB Electrical Systems than to depend on the Internet Archive. Too many old sites now have 'bots that block your access to even archived info.
Bob Muenchausen

Texas Instruments part number UA7810CKC. However, here's the link I stumbled across while searching for the part number:

http://www.nicolamarras.it/tr4/techtips/voltage_stabilizer.pdf#search='Texas%20Instruments%2010%20volt%20regulator'

This points to original instructions from the MG Cars Enthusiasts Club, for both the fixed and adjustable replacement regulators. If you have trouble, email me and I will send you the PDF file I downloaded

Paul, my wife is mailing a package to you. Ignore my request to return the instructions, since I will no longer need them.
Fred Doyen

Well, the link didn't come across too well, but you'll know what to do with it. Copy and paste the entire line into your browser address window, and execute.
Fred Doyen

Also here:
http://www.freewebs.com/classicstabilizers/
Robert Dougherty

Hey, Bob, great link too!! Thanks!! You too, Fred!! This is what makes this BBS great.
Bob Muenchausen

This thread was discussed between 18/09/2006 and 28/09/2006

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