CTC-7 metal table top

[DaveWM]

figured I should start a thread with a good title

some action started, trying a few things on rust removal, followed with some shots of the fly cage and finally the chassis

[DaveWM]

the chassis only has a little bit of surface rust on the back corner near the HOT.

All the tube shields were badly rusted, and the shield on the tuner was also badly rusted. Lastly the fly cage was a mess. Very few papers, so should be an easy recap to get to a test run stage. I will replace the top hat that had a rusted off lead, check the B+ for shorts and if ok will try a slow start with the HOT and VOT pulled.

[DaveWM]

the horz centering pot was a little bit stiff, some lube spray helped but I will test to be sure its not open. I have had problems with those before.

[Eric H]

Let's see some pics of the cabinet! Is it a Blonde by chance?

[DaveWM]

http://videokarma.org/attachment.php...0&d=1361386075

its in really rough shape, lots of rust on the inside and surface rust ruining the blonde faux wood finish.

[DaveWM]

did a little more cleaning, replaced the broken power diode, checked the plug resistance 150 ohms? oh yea the thermal switch. The B+ was about 10k thats good and it started out at about 3K so the filter caps don't seem to be shorted.

So next up will be the jump the thermal B+ AND jump the heater since I will be using a variac. Monitor the B+ and see how she goes.

Almost all of the tubes were heavy with corrosion on the pins, I used a wire brush and contact cleaner. I will prob have to work over the tube sockets as well with the dental brushes and cleaner.

The vert out looks like it was chewed on by something at one point, but I have a NOS one of those, same with the horz eff coil, but also have a backup.

The G1 and G2 pots are hidden behind a bolted on cover (nice) and were mostly frozen. again cleaner and lube seems to have gotten them going, but I may replace them all, I hate crappy pots, and I dont think they are anything special.

[miniman82]

You like to live life on the edge, huh? I personally won't give an old cap a chance if it gets slightly warm, that just means it's past its prime and likely won't smooth out the voltage well at all. It will act like it has reduced capacity, so ripple will be higher as will leakage. Why not just put new ones in? It seems such a small price to pay for transformer protection.

[DaveWM]

I will prob do just that, BUT I like to base line a set and I know the caps will last long enough to test the HV and basic function of the set. That being said I have many sets built a little later than this (mid 60's) that have been running fine on the orig caps for a couple years now. I will generally test a can cap and IF it test well after all this process then I will leave it be. I don't really think I am taking any big chances since I will be putting a very conservative B+ fuse and ad a thermistor to absorb the inrush. Besides sometimes I wonder if new caps are really all that great, I use the best I can (nichicons 105c rated) but still wonder if they will last, esp since I have 40 year old caps that work just fine.

My main concern is to not introduce any possible errors and then replace one can at a time (if the fail to come around). I do replace all paper based caps (wax cover, Bumble bees, etc...) as I know they always leak, prior to any full power test.

[DaveWM]

I after the GE detour, I finally got back on this set. Replaced the 2 .47's in the fly and put the cage back on (to avoid any oops's with the fly out in the open).

Mostly has brown drops which often are ok, so I went about replacing some the ceramic tube elmenco caps (some were replacements done in the past).

there was a bumble bee on the primary of the audio out, and there is one in the IF that looks to be a pita to do as its got the solder on bottom shield. I am tempted to just do a j hook from the top replacement, I dont like unsoldering those covers, alway worry about a slip of the iron then melting down some insulation. there are a couple single electro as well, one on the video bd and one in the chroma section. those will get replaced as well before the initial power up. Nice to see the use of better caps on this vs the CTC-5 which had ALL papers.

[Sandy G]

If you wanna take care of the rust business PERMANENTLY, on the inside of the cabinet, there's this stuff called Duro-Extend that I can HEARTILY recommend. You brush it on, it looks like watery milk, smells worse than Sh!t, & dries to a purplish tone, over which you can then paint. It bonds to/with the rust, & then the metal's protected for good. I would imagine any good industrial paint store would have it. I would imagine the salty air in Orlando wreaks havoc on things that were haphazardly painted, like the inside of TV cabinets...

[DaveWM]

I could not bring myself to doing a 1/2a$$ job on that cap in the IF board, so managed to remove the shield and replace it. That should do it so I hope to try it out soon. I know one of the filter caps have to be replaced as it still runs warm after my extended reform process.

[DaveWM]

whoo hoo whe got a raster!!

time to leave it alone for the night.

[DaveWM]

todays project will be to check all the tubes (yea I only did some subs on the HV tubes to get it working thus far), see about installing a cathode fuse on the HOtube (or at least a test point that is easy to get at).

there was some issues with the 1st start up, the drive to the HO tube was not right, very small PP and way to fast (like 8x fast) It seems to start out this way and then pops in as the H tube warms up. Not sure if its just a tube issue or one of the feed back caps in the H board may be an issue. I will check out some of those mica caps as well if a tube swap does not settle it down.

I need to get some correct fuses (the kind with the ears on one side) but at least I know the fly is ok, so I am willing to spend some more time on it.

the vert sweep was not full, about 4" short. I dont know if it was a mis adjusted pot (as I had cleaned them) but if not then I will need to check the electro in the cathode circuit, pretty sure its in a can as I could not see a single anywhere on the board.

My shop is in a bit of a state of flux, so I am having to work on the floor, in the garage, on top of boxes etc... not the best situation.

[DaveWM]

ah ha, a 1.8 meg plate load resistor in the H osc tube is reading 12+ meg. bet that has something to do with it. Turns out the is no cathode bypass electro cap in the vert out anyway. Since its a plate load resistor just another reason to get out the tube tester and check for shorts.

[sampson159]

looks good!those sets were a bear to converge.this one is almost perfect