Hi Tri-comp/Torben,
Sorry, didn't pay more attention to new posts, as I had and still have more important things to do (work), so not much time available to work on the Capri. Sounds really interesting about working as an apprentice in the 70'ies. I wish I knew that you had all the required tubes - already bought an extra set.
One thing I noticed about the AW43-88 heater is that it glows extra bright while the set warms up. It did not do that before while the set did show a raster.
I also got myself a Müter BMR7 CRT tester with the appropriate adaptor.
The BMR7 also allows connection of an amperemeter to measure the filament current draw, and I have some bad news: It draws about 600 mA at 6.3V instead of 300 mA, and glows brightly.
The CRT of the 21" Capri (AW53-88) draws 290 mA at 6.3V and glows normally, as the AW43-88 used to do.
The BMR7 does not report any shorts on the AW43-88 (or the AW53-88).
Can the filament suddenly become half the resistance? Is this a known issue?