XJ750 rebuild - electrical issue

I recently purchased a non working 83 XJ750 K. The seller told me the issue was in the TCI. He deduced it was the TCI because he had a second which fired the other 2 cylinders. I went over the bike, checked compression, grounds, cleaned out the carbs. I got it running today, on only 2 cylinders. Going through electrical tests, I found that the rectifier might be no good. I did a voltage test and found less than a volt.
My question is there another test I could perform on the rectifier and could the rectifier be the cause of the TCIs burning out?

 

A service manual will tell you how to test the diodes in the rectifier/regulator. If you don't have one then I suggest getting one, its valuable information.
Possible the regulator/rectifier might have put out too much voltage to harm the TCI, I doubt it though. If there is not enough voltage that can also cause problems, but not preminate dammage to the TCI. Get the charging system working at the correct voltage before condeming the TCI. Check all the connections in the TCI circuit and the ignition coils then go from there.

 

maybe coils, which 2 are firing ?

 

1 and 4 currently. If I switch TCIs 2 and 3 fires. Turns out the Tach is controlled by the 2 and 3. Took apart the whole tach and most of the harness before I figured that out.

 

Sounds like the PO was telling the truth.

 

I did the diode test, out of the Haynes manual, and I got no conductivity, forwards or reverse. A little strange to me, how can all 6 diodes fail simulatenously?