Originally Posted by 68LANDYACHT
After researching this site for awhile, I decided to try and repair my dead Univolt. I acquired three 450 v. capacitors from a local A/C supply business and replaced the 650 v. originals. The told me at the A/C business that you cannot reduce the size of the capacitors, only increase the size. But, for 12 bucks and change I was going to try anyway. Well, the once dead Univolt immediately hummed to life after soldering in the new capacitors. It cranks out 12.8 volts which I think will be sufficient.
The transformer produces 6 VAC and that is supplied to the rectifier diodes. But there is in the circuit the cpacitors which turns it into a voltage doubler circuit....hence 12 V pulsin dc. the battery acts as a filter cpacitor stoing voltage to produce smooth DC Volts. This is a comm0on failure and your selection of 450 V cpacitors was sufficient to work.
I have done this on several units brought to my shop.
Rae Electronic Service Lab