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Regulator RB106/2 Caveat Emptor

Posted: Thu May 14, 2026 5:10 pm
by geoberni
I thought the Caveat Emptor was quite appropriate for this discussion, given the seller location.

I was browsing FleaBay and looking to see what vintage RB106 units might be around; not that I actually need one, I already have 2 spares in the garage :roll:

I saw this one, being sold from Italy just under £50 with over £81 shipping, so having a laugh there for starters.
Browsing the images, the condition looked quite fair for 1967, but I immediately noticed this.....
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Ummm.JPG
Ummm.JPG (51.91 KiB) Viewed 5257 times
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A & A1 shorted together.
I suspect this may have come from a car with an alternator conversion and the RB106 has been used as a Junction Box. Anyone who just sticks it in the car to see if it works as expected may get a surprise.
We've seen a form of this before in the forum : viewtopic.php?p=683045#p683045

Unlike when that topic was posted, I now know what the result is; it's bypassed the Compensation Coil so the Unit doesn't recognise when the load increases, e.g. switching the lights on.
The Dynamo may therefore work too hard and overheat, possibly boiling the battery or just setting fire to some wiring.... :roll:
Always take car when buying old electrical items... :tu1:

Re: Regulator RB106/2 Caveat Emptor

Posted: Thu May 14, 2026 6:09 pm
by svenedin
Interesting!

If one goes to autojumbles there is usually a selection of RB106 regulators. Remember that you can make one good one out of two if you have some basic skills. For instance, often there will be units with broken lids, cracks or bits missing from the Bakelite case but they have perfect internals. Then there will be wrecked internals and perfect case examples....

Stephen

Re: Regulator RB106/2 Caveat Emptor

Posted: Thu May 14, 2026 6:38 pm
by myoldjalopy
Caveat Emptor indeed! A second hand regulator may have been working fine when it was removed from a car - but where has it been stored since - and for how long? Has this caused corrosion? Do the cut-out and regulator switches still operate properly? These things can, of course, be bench tested, but this may not be easy for some owners without requisite knowledge and equipment. A lot of these items on Ebay are listed as 'untested' and, even at an autojumble, unless the seller can absolutely guarantee the item, it is a bit pot luck.......