If it works in one range, there's most likely nothing wrong with the video amplifier, the chopper amp and the thermo couple. Your problem is most likely a dirty range switch—simply clean it. And: Please don't mess with the thermo couple!
Thomas - thanks, that's on the list. And I am not going to
mess with the thermocouples, I am going to
experiment with them.
Seriously, if cleaning the range dial doesn't fix it and there's no obvious problem with the attenuator deck, I will follow the service manual procedure for testing the thermocouples. As for the fuse holder, I've decided to replace the back panel, as this one is seriously bent and impossible to make right. As noted below, there's a parts mule on ebay that may serve the purpose.
There is a parts mule here, it may even have one of those awful IEC connectors too. The previous owner EOLed the thermocouples and because they couldn't be arsed to fully screw it back together or pack it properly, the meter got busted on it's journey here.
David
David - thanks for checking your stock. Last night, I found an ebay offering, as-is, two units for fifty usd shipped. They both have the "modern" AC socket, which I'd prefer. I am going to make an offer on them and see what happens. I will let you know if it doesn't work out.