Given that these can be quite sought after and are highly regarded pieces of hi-fi kit, I don't plan to do anything too extreme with mine.
This page gives some idea of how highly regarded they are even now - One Thing Audio MPX1/MPX2
But, I would like at least one to be capable of stereo, so here goes .....
Setting up a Trough-Line with no test equipment
This was how I went about getting my 1957 Trough-Line into working order. OK, so I do actually have some test equipment, but the following proved to be a very quick way of checking that the thing was working and getting it into a reasonable initial alignment.
1. Visual inspection. Always important with old electronics. There was one small electrolytic on the underside of the transformer that had leaked. I replaced this. Fuse was OK, one bulb missing (not important) and the valves looked OK. I have a tester so was able to check these, but they were all reasonable (not like new, but good enough).
2. Added earth wire and powered on.
3. Connected aerial and amp. Only slight hum at full volume, nothing else.
4. Connected audio out of working trough-line to volume control of through-line being tested. Ouptut stage fine.
5. Took IF signal from working trough-line to one being tested. Adjusted core of detector transformer to give strong output.