I have an FR-101 that is deaf also.
It could be a dozen things wrong. Oscillator board, etc, etc.
The FR-101 has a built in signal generator operated by a switch inside the radio to test.
You need to get the manual if you don't have one.
There is a good you tube on it with possibly your problem.
If all this is not what you want to undertake RETURN IT. The "no returns" is BS, and unless it was sold as "parts not working" eBay will refund you all your money PLUS return postage.
Just last week I got a meter that didn't work. I contacted the buyer who said no returns. I contacted eBay and within 3 days I had a return label and in a week a full refund.
With regard to not finding anyone to work on the radio in Ireland............That problem is everywhere today on the older tube and hybrid rigs. Without an O-Scope, and a multitude of other test equipment, it's hard to do the work yourself.
It sounds like the return is the best option for your repair experience. Though you could learn a lot by digging into that 50 year old receiver.