Did Hans Berliner win the world ICCF championship using computer help? Way back when, Hans Berliner worked for IBM.  I met him at an IBM data center one time, but he worked in the Federal division and just used the center for a demo. I had known him from the Washington Chess Divan earlier.
I know he had done a computer program to help with chess. It was the first as far as I can tell. This was in the days when the s/360 was ruling the market, and there were no PCs, and pdp8s and the like were not up to the job although they did cause IBM a lot of grief by their cheap price and what they could do for small special-purpose jobs.
The question I always had was did Hans use the IBM computers to assist his game when he won the ICCF world championship? I know that Hans was very good as a player,  but was he so good that he could have won the ICCF world championship without the computer's help? It is certainly possible, but having a really good computer analysis on some tough positions had to be helpful.
Short of asking a deceased man, I would say that the answer is "no way".

He won the 5th World Correspondence Chess Championship in 1965. Computer chess, if it existed at all, was not strong at all. Even with mainframe-type hardware back then, it paled on comparison to the first Chess Challengers of the early 1980's, and they were only rated about 1200 then.

My first chess computer in 1985, and it was the strongest and most expensive on the marker at the time, was only about 1600. There is no way that you could win against correspondence Grandmasters with that type of help.

I would say, fairly confidently, that is was all his work.