Director 21 resto begins....

[miniman82]

I was not content to stop at having a waveform, as the next day dawned. Something about finding life in a 56 year old chassis gets me going, call me crazy. So after finding the horizontal oscillator working, I decided to pump as many new caps as I could find into critical circuits to see what else I could get. I ended up doing everything on the 2 PCB's, everything in the vertical oscillator, everything in the horizontal oscillator, and a few other random caps just to exhaust my supply. I'm now totally out of .047's, .022's, .01's, and the 'lytic bin took a good hit as well.

Turns out the vertical section is just fine as well, though the 6AQ5 running the show tests barely into the green scale on the tube tester. I'll have to get a fresh one before attempting to run a CRT. As you can see in the first 2 pics, I did a whole lot of recapping. Took me the better part of the day to get to this point, my back is killing me. I'm way ahead of the power curve as a result though, I figure there's only about 2 more days of recapping to the matrix section (3rd pic), and the chassis will be 100% free of PIO's.

Tidbit: every single paper cap in this chassis was made by Dumont...strange?
Most were MicaMold labeled made by Dumont, a few were were Aerovox and 'MicoMould'. I left the ElMenco micas in place, as every one I tested was within tolerance. I'll probably get to those at a later date, when I'm not so tired of capacitors.

The one bad part I found so far was a video peaking coil that had split it's case all the way around. The wires inside were eaten by corrosion, so it's toast. If I can't get another one, I'll have to wind one with the help of my brother.

[miniman82]

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!

[old_tv_nut]

I hate to tell you, but you also let the vacuum out of that 6CB5

Really, great progress! Keep us informed.

[old_coot88]

Originally Posted by old_tv_nut

I hate to tell you, but you also let the vacuum out of that 6CB5

That's whutcha call a sacrificial anode (and cathode too):
http://videokarma.org/attachment.php...5&d=1290924895


Bill(oc)