RCA CTC-16XL Suggestions/Tips

[Yamamaya42]

Originally Posted by Rocket

That's awesome! : D

I tend to take my inspiration from something about a decade sooner Darkstalkers!

[Rocket]

Originally Posted by Yamamaya42

I tend to take my inspiration from something about a decade sooner Darkstalkers!

Cool

[Electronic M]

Originally Posted by Rocket

Progress update,

New 6kv cap arrived so I thought about getting that knocked out. Got it pulled out and it was 3 times out of range on just my multimeter. While having that out, I also pulled that 4.7 meg that was at 6 meg that was connected to it to replace it as well. connected up with this 6kv cap is a 6kv 66 meg crazy looking resistor. It reads completely open O.o I was not sure if there was a special way to test such a resistor, but I would figure a resistor is a resistor right? I should get 66 meg give or take. So if that is bad where about do I even get a resistor of that size? I could not find one on mousers.

Next, I don't how I missed this when I looked over everything under the chassis and cleaned up the controls, but the Service/Normal switch is burnt to a crisp O.o and is even missing part of its wafer and 3 of the 4 connection points broke away from the switch. Not sure what would cause that switch to burn up like that.. Anyone have an idea where I could pick up a replacement switch?

Most DMMs don't measure as high as 66M and indicate open on anything 1 ohm above whatever their max range is. Odds are it is still okay. If it is actually bad you can take a few xxM ohm resistors of lower value and make a 66M resistor (resistances in series add)...I did something like that on my 21CT55 about 6 months ago.

[Rocket]

Originally Posted by Electronic M

Most DMMs don't measure as high as 66M and indicate open on anything 1 ohm above whatever their max range is. Odds are it is still okay. If it is actually bad you can take a few xxM ohm resistors of lower value and make a 66M resistor (resistances in series add)...I did something like that on my 21CT55 about 6 months ago.

Thats cool, I will leave it be for now until I have a way to properly measure it. I will get the other parts replaced and see how the focus control works.

[Rocket]

Update;

Its looking pretty good, not quite perfect yet and still got work to do until I am fully happy. I still have not found what has the horizontal centering pot control out of alignment. Also the focus control still does not work after replacing the 130pf and 4.7m resistor. I wonder if the pot is any good or if its something else causing a problem. But it isn't too far off from where it needs to be.

Moving the convergence coil up to that mark on the neck of the picture tube did the trick! and the convergence pot controls work much better.

I also can't do the grey/white setup until the replacement service/normal switch shows up and I figure out how to undo and fix that mess. Its a bit off from when I cleaned the pot controls, but it isn't terrible.

Thought id give it run for a few weeks and see how everything ive done so far holds up and works. Got everything put back together and move it up to the living room. I then thought maybe I may pull that back cover back off so it can run cooler.. but its nice having the original back on it.

I am surprised how close the colors are to my flat panel and how nice the picture is on this set, though its not perfect yet. even the audio is pretty darn good. I really love this TV set.

[old_tv_nut]

Nice!

Call me a worry wart, but it always bothers me to have the back off a set off when it's on a wall with a picture hanging above.

[Electronic M]

The original backs give plenty of ventilation. What I'd do is drill a few holes in the base of the HV cage and a install a fan at the too to draw hot air out. If you're really worried about too much hot air in the cabinet hook a fan to the top inside of the back blowing out.

You can bust the CRT neck way too easily without the back on.

[Yamamaya42]

Originally Posted by Electronic M

The original backs give plenty of ventilation. What I'd do is drill a few holes in the base of the HV cage and a install a fan at the too to draw hot air out. If you're really worried about too much hot air in the cabinet hook a fan to the top inside of the back blowing out.

You can bust the CRT neck way too easily without the back on.

I'm thinking of doing that to mine, once everything is all done, but I can't decide on an ac or a dc fan, would brushless dc fan be OK with all the RFI and xrays in that cage? or would AC be better?

[Electronic M]

Either would probably be okay. My 21CT55 has an old 12V computer fan (straight from my PC junk bin), running off 6Vdc of rectified, filtered heater voltage.

It is only rated to draw about as much current as a 12AX7 running at 12V so at 6 it should draw around half that. At 6V a noisy high flow 12V case fan runs quiet and moves plenty of air for a small HV cage.

[Rocket]

Great points! Id sure hate for that picture to fall off the wall and hit the neck of my picture tube! I was feeling a lot of heat coming from the back of this set last night after about 4 hours of running.

I did drill holes in the top of the HV cage as well as 2 bigger holes in the bottom of the HV cage.

I have not yet installed a fan but have been thinking of the best way to do that. And some great ideas posted here.

Tom, did you do that fan inside of your HV cage? I know they make some smaller sized computer fans that I probably get to fit into that cage. What do you think of pulling off the heater power from focus tube, the connections are right there inside of the HV cage? I even thought about placing a normal sized PC fan under the chassis blowing up under the HV cage drawing in cool fresh air from below.

Also, so far it seems that sanding that HV reg cap down with some fine grit paper and covering it with that silicon, so far seems to have stopped the leakage. not sure how long that fix is going to last. I have been occasionally turning off the sound and listening for it.

I have noticed today that the convergence has drifted out a bit, I kinda figured maybe this would happen as the new parts break in? I will give it another good few days of working before realigning it again, maybe just wait till this weekend and bring it all back in.

Anyone got any suggestions on doing grey/white scale setup without having a usable service/normal switch? I have the RCA book that explains how to do purity, convergence and the grey/white black/white setups. and I can tell its off a bit and I had to eye the blue/green/red screen pot controls since I move them all out of adjustment when I hit them with contact cleaner and lube. I may just have to wait until I get the new switch and get it installed.

oh! I got about a total of 10+ hours so far on that 250ma fast blow fuse since I installed it so far with no problems : D

[old_tv_nut]

You can do minor gray scale tracking on a picture, but it's best if it's a still test pattern with a full range from black to white, like color bars. And it's really best to have the service switch. The problem is that the brightness control and G2 controls have similar effects on the picture, so it's hard to tell if they have been set in opposite compensating directions. The service switch puts a fixed bias on the tube so that when you adjust the G2's you are setting them for design center normal cathode and G1 voltages, and the video output tube has the fullest possible range available.

So, yes, you can tweak the G2 controls, but when you get the service switch fixed, you may find that all three are off by some amount.

If you want to play with it now (and maybe have to readjust later), the principle is to turn the color all the way down, set brightness to mid range, and make the blacks just black and colorless, and the dark grays also the same gray as the highlights, with the G2 controls. Then if all the shades of gray from black to white are off color (but are the same color, that is they are tracking), adjust the green and blue drive. You may have to go back and forth from drives to G2s a time or two.

It's the setting of brightness arbitrarily to midrange that may cause a discrepancy with the service switch procedure, but what the hey, if you want to try it, go ahead.

[Electronic M]

Originally Posted by Rocket

Tom, did you do that fan inside of your HV cage? I know they make some smaller sized computer fans that I probably get to fit into that cage. What do you think of pulling off the heater power from focus tube, the connections are right there inside of the HV cage? I even thought about placing a normal sized PC fan under the chassis blowing up under the HV cage drawing in cool fresh air from below.


Anyone got any suggestions on doing grey/white scale setup without having a usable service/normal switch? I have the RCA book that explains how to do purity, convergence and the grey/white black/white setups. and I can tell its off a bit and I had to eye the blue/green/red screen pot controls since I move them all out of adjustment when I hit them with contact cleaner and lube. I may just have to wait until I get the new switch and get it installed.

The customer's CTC16 I did I never installed a fan on the HV cage. Given HV arcing tendencies I would never install a fan on the inside of better than 95% of the sets I've seen... The CTC16 seems like an especially bad choice for an internal fan. I'd also strongly advise against powering the fan from a flyback winding... you will probably cause more extra current/heat in the flyback than the cooling the fan provides can balance....use the heater winding on the main 60Hz power transformer or a separate power supply for the fan (you could wire a wall wart in parallel with the main power transformer so the fan comes on with the TV power switch).

Blowing up from underneath is a valid approach. On my 21CT55 I glued a fan to a 3" PVC pipe section about 4" tall. The PVC sits on top of the cage over a factory vent hole that has a bulgy cover and extends that vent into a duct for the fan which pulls hot air out of the cage. I used the two power leads to tie down the fan/PVC assembly to the chassis so it won't be displaced in normal use.
You could pull a vertical yoke lead with brightness at min and adjust the screens or pull the vertical output tube... I've done it both ways in sets that lack a service switch by design.

[Rocket]

lol if I would have thought about that fan in the HV cage for just a moment I would have realized how bad idea that would be as well as I have been thinking of going ss on that to lower the heater load to help the flyback..

well it can't hurt to get some practice setting up them grey scale settings. I will also try pulling the vertical tube as well and try it that way as well and get a feel for things.

The RCA book mentions flipping the kine bias switch and video peaking switch. I am curious the operation behind these switches and what they do?

[old_tv_nut]

You would change the kine bias setting if you can't get the correct result on one or more guns when adjusting G2. This should be part of the adjustment instructions.

Not sure what the peaking switch has to do with gray scale, would expect it to only affect picture sharpness.

[Yamamaya42]

Originally Posted by Rocket

lol if I would have thought about that fan in the HV cage for just a moment I would have realized how bad idea that would be as well as I have been thinking of going ss on that to lower the heater load to help the flyback..

well it can't hurt to get some practice setting up them grey scale settings. I will also try pulling the vertical tube as well and try it that way as well and get a feel for things.

The RCA book mentions flipping the kine bias switch and video peaking switch. I am curious the operation behind these switches and what they do?

no two CRTs are alike, nor do they STAY the same in their lifespan , I'm pretty sure those switches are there to adjust for subtle differences in CRT gun outputs , and to adjust for how they may change as the tube ages.