#1
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Convergence issue right and left R/G
Been fussin with the final registration on a CTC-16 and right and left sides were way off to the point of affecting purity in that area. The answer was in plain sight all along. When recaping a set, don't forget the convergence panel! I don't have a cap checker that applies voltage so when I removed them I checked them anyway on a digital unit I have and they checked as marked.
The replacements however made all the difference and I can get almost perfect convergence. The .082 and the .12 were replaced with .1's and I still had adjustment range either way. This is a set put together from a combo and put in a standard cabinet that I striped and refinished. I'll post some pictures soon. All it needs is some Hang-Tags. Last edited by 6GH8cowboy; 08-16-2013 at 10:30 AM. Reason: add photo |
#2
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It looks really nice, and I think many will be impressed when you post the pictures.. The actual cabinet use to house a set exactly the same.. Only thing that's different are the serial numbers not matching back cover and chassis... The pic tube tested almost new on all three guns.. It's a Colorama rebuilt..
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#3
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This is the same chassis that was taken out of that combo listed here in this thread..
http://www.videokarma.org/showthread.php?t=259193 My my what a beauty.. Dave you did a great job.. This is an actual cabinet that fits the exact chassis and bezel style.. We maybe the worst creatures to do such a thing to some.. |
#4
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That's a good tip! I never thought about recapping the convergence panel, although I've replace that selenium rectifier a few times for leakage, and of course found a few boards with missing coil slugs, torn windings, and burnt-up pots.
Charles
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Collecting & restoring TVs in Los Angeles since age 10 |
#5
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cabinet look really good.i do wood working also and shame the combo was parted out but this is a fine looking set.
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Audiokarma |
#6
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Thanks, he did a great job...
Last edited by tvcollector; 08-22-2013 at 10:45 PM. |
#7
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Adjustments are done and ready to go home with TVCOLLECTOR. Dust not included.
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#8
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Rock Hudson Lookin' Good
Saw that movie yesterday before Work !
Lookin' Good !!! |
#9
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There's an issue now.. Picture is not so bright with a reddish tint.. It would flicker back to normal, but then it got worst. I would change the channel and it would correct it, but that doesn't work now.. Tint doesn't take much effect.. All colors are still there, it's just the picture is alot dimmer with a reddish tint.. And it didn't gradually get like that, it flickered to that.. I'm thinking a tube or capacitor or resister problem.. I hope it's not the picture tube..
When the set is powered off, it seems to do the normal down to a bright white line still.. Last edited by tvcollector; 08-29-2013 at 03:35 AM. |
#10
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voltage checks (of crt pins) are in order to diagnose CRT brightness problems. this will point to what area to look into.
common problem to watch for on ALL ctc-12 thru 17 at least are chroma board ground stakes and Jumper wires that run on the top of the pcb. checking the -y amp plate load resistors for heat would be a good start as well. Question for Dave C, did you replace the .01 grid coupling caps of the 6GU7 -y amps? EVERY rca of the era had a problem with the cap that is between the tube and the power resistor (the middle 6GU7 tube). It would test "funny" not leaky but the eye tube would be fuzzy. The two other -y grid caps were often fine, I assumed it had to do with the hot evviroment (sandwitched between the tube and power resistor). While it did not seem to matter, I would replace it anyway (no real change was noticed in the pic). My read on this is the cap is not only responsible for passing the chroma signal but also part of the DC restoration (rather than the more common use of a diode). cycle the bias adj and service setup switches a few times. wiggle tubes on chroma board. check jumper wires confirm CRT pin voltages check HV Last edited by DaveWM; 08-29-2013 at 10:38 AM. |
Audiokarma |
#11
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Yep, the 27k plates, .01 grid caps , 100k CRT resistors, ground stakes, PCB jumpers (orig were gone), and new 6GU7s. CRT grid volts will tell the story real quick.
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#12
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Weak static magnets?
Not as pink as expected by a long shot. Turned out to be a dead spot at the wiper on the green drive control. Returned to normal when touched and after a couple of turns to excersise it, no problen at all. Touched up the purity. it looked like it changed slightly after the ride home the other day.
In setting up this set several times I have observed the static convergence magnets are at their extream ends of their range (some almost touching the glass, some barely still in the slider) to get proper center registration. Adjusting the purity even slightly causes a moderate interaction with that center convergence. Could the magnets be so weak that they are influenced by the purity rings or just a picky gun structure? |
#13
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did you try flipping them over? I have always had purity upset center convergence.
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#14
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Oh yea Dave, flipped and even tried reversing the purity rings once. Don't get me wrong, it is set OK at this time. It just seems that there is more interaction than what I usualy experience and red purity is extreamly critical. If this were a rectangular tube I'd suspect the shadow mask was warped or popped loose, RE the purity issue.
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#15
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take out magnets and rub another bigger magnet on them.we did this a bazillion times back in the shop days.keep a 1 pound magnet in the drawer just for this.
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Audiokarma |
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