Last day of work to the CTC-4 for this weekend. I decided that after the success of getting both oscillators up and running, I should go for broke and see if I couldn't get some HV flowing.
I wired some 10-meg power resistors from the HV tower to ground as a load, and let 'er rip.....
Nothing. Not only did I not have any HV, but the previously observed waveform at the HOT grid was mysteriously gone.
I couldn't find anything at all wrong with the horizontal oscillator, then I pulled the HOT and damper out. Come to find, the HOT had a short which shunted the grid to ground, which explained the loss of a drive signal. I don't have any spare 6CB5's around, so I subbed in a 6CD6 for testing (not same ratings, I know!). Still nothing. Tested the 6AU4 damper next, and it had 0 emission. I was beginning to think the HV transformer was bad at this point, since both tubes that run it had gone bad...dramatically, as it turns out.
In the pic, you can see what's left of the 6CB5 HOT. It burned a hole right through the plate on both sides! Cathode was done for too, and the grids were melted.
But my fears were proved wrong about the HV transformer. I put a new 6AU4 in along with the 6CD6, and while the 6CD6 did not like being put in the position of having it's ratings exceeded, it did drive the HV transformer for long enough to let me know HV was working. I saw the normal blue glow from the 3A3 rectifier as HV came up strong, and the power resistors got nice and toasty after a short run. I'd call this a very productive weekend, all in all.
So to 'recap' recent events (pardon the pun!):
I now have a redone power supply, 2 good oscillators, good HV, and all that remains is the matrix recapping before I can take this thing on it's maiden voyage with a real picture tube! Nothing but excitement on my end!
