Along with the Hitachi I have acquired a Mitsubishi CP-145B. This is another set that I am led to believe was once in the hands of crustytv.
On setting this one up, I was able to find the Sky box signal in colour and the signal from the JVC video but no colour. It did need the hold controls adjusting - they are on the front of this set - and the picture was very grainy, but I had been advised of its poor gain. The tuner door also does not close firmly, leading to the AFC switch not remaining depressed, but that may be fixable if I warm the latch and flex it out slightly.
Until the poor gain is corrected, it will probably be difficult to obtain colour on the JVC output. Picture geometry, though imperfect, is not far out. One oddity, which may not be a problem, was the appearance of coloured dots near the centre of the screen after switch-off - not converged - though there was no sign of any convergence error on testing.
I don't have any servicing information for this set, though I believe it to be similar to the CP-140B which is mentioned in Radio and Television Servicing 1974-75. I am on the lookout for this.
Sounds like a lack of "switch off spot suppression" - Different makers had different ways of doing it, and a circuit diagram will be invaluable in tracking it down, unless someone on the forum has a good knowledge of the set in question.
Definitely not a convergence fault though, which is one good thing.
This set has two power switches, which might leave the CRT heater powered aka Instavision?. The main switch is a rocker at the front bottom right.
Did the Hitachi CNP190 display similar artefacts on switch off, it was another Japanese set but not Mitsubishi, it would have been a Hitachi or Toshiba.
I don’t know about Mitsubishi but the Hitachi models such as the CFP470, CNP680 & CNP190 carried out auto degaussing at switch off and not switch on via the switch on the front of the set. This resulted in the strange effect as the scan decayed. I suppose this was so as not to spoil the instant on effect of the picture, of course if you switched off with the mains switch at the side then degaussing could not occur.
Hitachi PAL-1 and PAL-2 sets degauss on "main power on, pull switch in standby", which is of course the situation at switch off. I haven't noticed anything odd scan wise at switch off apart from a brief but noticeable field collapse on my CSP680. On the other hand I've not had it very long and have decided it needs a dust bunny eviction from one side before I try it again, as part of dealing with the appearance of smoke the second time I tried it. I was too young to notice anything as being odd on the CEP180 we had.
I have not investigated the Mitsubishi that far yet, but I know that at least some of their models had "quick start" like the Hitachis did. The slight plus is that the CP-145B has a standby indicator.