RCA 6T75 Restoration (16GP4)

[dobulee]

Thanks for the input,

I'll take a stab at the heat and twist method on the next twist lock.

I have access to a wide array of HV capacitors, so getting 1kV 5% Films in just about any value isn't a big problem. I'll ohm out, and hipot test the Flyback and vertical oscillator trans. before firing the set up for the first time.

As for the line caps and line resistor, my work in the power electronics industry tells me that the line caps are there as much for RFI suppression from the set out to the world, as for the world into the set. Without them I imagine you could get some local oscillator noise out onto the line which would interfere with other sets. However, I doubt the single order filter really works any miracles -- modern RFI filters are quite an artform in themselves! I'll put in new Y2 safety grade ceramics. I have an isolation transformer at my disposal as well.

[dobulee]

I was replacing caps around the vertical oscillator, and something didn't look quite right --My first schematic change!

Sam's shows the vertical oscillator as a 6J5, where as the RCA chart in the cabinet shows the 6SN7 Dual Version. 1/2 of the 6SN7 is connected exactly as the 6J5 would be, with the other 1/2 pulling duty as the synch amp, where sams shows 1/2 12AU7. The 6SN7 is biased differently than what is shown on the 12AU7, but I guess that is to be expected.

Things get even weirder upstream of that at the DC-Restore/Synch Sep tube, where my chassis bears little resemblance to the Sams schematic. There appear to be both halves of a 12AU7 interconnected up there, where sams shows only 1/2.

I haven't fully traced out that schematic yet, but if I get time, i'll do my best to plot it out.

For what its worth, my Sam's guide for the 6T75 shows chassis KCS47, A; where the actual unit is stamped KCS47AT. Does anybody have this particular schematic? Right now i'm pretty much operating on the 'Blindly replace what is there' technique with no schematic of some sections.

Other than that, a few pics of the re-leaded transformer. Luckily wire is available in all colors under the sun!

Alex