Voltage Regulator Modification

Just when I thought I had Tom Wilson’s White GTE’s electrical system sorted, the voltage regulator stopped working. I had this unit tested, and it was working fine for days installed in the car, but last week, I started to notice the ammeter showing full charge all the time. On closer inspection with a meter, I confirmed the VR was stuck in full charge mode and overcharging the battery. Old electronics can sometimes simply fail and this unit may have simply burned out after sitting dormant for so many years. Either that, or it’s suffering from Bartleby’s Syndrome.

A few months ago I suffered the same problem with my personal car and I replaced the Magnetti Marelli VR with this simple solid state unit. I noticed it might be small enough to install inside the original VR, but never had time to circle back and try.

With a second failure and broken Marelli voltage regulator, I spoke to my electrical supplier, and he suggested another unit that was even smaller than the one I got from him last time. Even though it was inside a larger steel box, my electrician knew it was much smaller internally.

With the cover off, you can see the electronics are tiny, and there was definitely a way to make this fit inside the original VR.

The first task was to gut the old electronics and decide how to mount the new internal electronics.

I ended up using some of the mounting plate from the new VR to attach to the old mounting points. I soldered the connections and put it all back together and I now had two functioning VRs with new internals for Tom’s GTE and my 330 America!