Potential new project! Color Admiral! - Page 10 - Videokarma.org TV - Video

Alex KL-1 · #**136** 03-11-2024, 06:21 AM

Oh, these intermittent PITA issues... if this tube don't reached audiophile prices, is worth to try.

Yamamaya42 · #**137** 03-11-2024, 02:48 PM

Looks like I'm not the only one who has been though the Maggie hell!

http://www.videokarma.org/showthread.php?t=269466

Yamamaya42 · #**138** 03-26-2024, 10:33 AM

It's still tending to act up sometimes, turned it on last night, color came on OK, then after 10 min, barber pole effect was back for 30-90 sec, then it locked in again for the rest of the night.

On / off a few times, stayed locked.
Very annoying.

MORE NOS tubes on the way,
2x 6KE8s (burst amp / color killer ) , for a total of 4, 1 original, 3 nos, ( no sub listed for this )
Yet another 6GH8A , used in 2 areas ( 3.58 osc & cont / chroma bandpass & horz blanking) I already have many of these.

Other suspect, 6LM8 (video cathode follower-chroma sync amp / 1st video amp) 2 on hand, original , 1 NOS, it's stated that 6GH8A is a direct replacement, but not sure how this silly thing will react to it.
Will just have wait for the new tubes and play musical chairs with tubes to see if anything changes.

It works MOST of the time, but the 10-15% of time that it does NOT, is aggravating!

vortalexfan · #**139** 03-26-2024, 01:08 PM

I'm not sure if this is of any help or not, but it sounds almost like your TV is electrically similar to my 1968 Sylvania Color TV that I'm currently restoring and my Sylvania TV is having similar issues to your TV (barber poleing, color not locking in correctly, etc) and the interesting thing is that my TV has no paper caps in it to speak of mainly mylar or ceramic disc caps, and a lot of carbon comp resistors, of which the 1/2W or smaller carbon comp resistors all measure within specs yet, but the 1W or higher carbon comp resistors all measured 10%+ high, and I've also replaced many tubes in my TV and still have issues similar to your TV, but I think the issue might be mainly related to the resistors that have drifted high, I'm not sure if that might be the case with your TV but it might be worth looking into.

Yamamaya42 · #**140** 03-26-2024, 08:54 PM

HA!
I caught it this time!
ran it for a few hours, the first hour no problem..
then it did it again.

shut out all lights took a look REAL close, V22 was out cold! (6KE8 burst amp / color killer ) , wiggle tube, lit up again, color came back! dirty socket? perhaps?

I did clean them, perhaps it's being stubborn!

zeno · #**141** 03-27-2024, 07:44 AM

Quote:

Originally Posted by Yamamaya42

HA!
I caught it this time!
ran it for a few hours, the first hour no problem..
then it did it again.

shut out all lights took a look REAL close, V22 was out cold! (6KE8 burst amp / color killer ) , wiggle tube, lit up again, color came back! dirty socket? perhaps?

I did clean them, perhaps it's being stubborn!

Or the PCB ground lugs to the main chassis.

Zeno

Yamamaya42 · #**142** 03-27-2024, 08:29 AM

Quote:

Originally Posted by zeno

Or the PCB ground lugs to the main chassis.

Zeno

Those were touched up, and looking at the diagrams, the ground traces to that area would have impacted substantially more than just the loss of color sync if that area lost it's ground, so far it seems that it is just V22 losing heater power due to a weak / socket connection, or a missed broken solder joint under it.
But , at least now I know the source of the annoyance!

vortalexfan · #**143** 03-27-2024, 10:54 AM

Quote:

Originally Posted by Yamamaya42

Those were touched up, and looking at the diagrams, the ground traces to that area would have impacted substantially more than just the loss of color sync if that area lost it's ground, so far it seems that it is just V22 losing heater power due to a weak / socket connection, or a missed broken solder joint under it.
But , at least now I know the source of the annoyance!

That's good to hear, now I know what to look out for on my Sylvania TV that I'm restoring when I start losing color and what not, because like I said my TV is more or less a copy of your TV (an RCA Clone perhaps?) more or less the same tube complement.

Yamamaya42 · #**144** 03-27-2024, 11:12 AM

It's not exactly an RCA clone, I DO see some RCA in it, but also some Motorola and perhaps even some Zenith, it's like they took some from all, and headed out in their own direction.

vortalexfan · #**145** 03-27-2024, 11:26 AM

Quote:

Originally Posted by Yamamaya42

It's not exactly an RCA clone, I DO see some RCA in it, but also some Motorola and perhaps even some Zenith, it's like they took some from all, and headed out in their own direction.

Interesting, I'm kind of surprised that's the case, so I wonder if Sylvania did the same thing then because when I was following your thread I saw a lot of similarities between your TV and my Sylvania I've been working on, although I guess that wouldn't be too surprising if that was the case considering Magnavox and Sylvania both ended up getting eaten up by North American Philips in the 1980s...

Yamamaya42 · #**146** 03-27-2024, 11:38 AM

This set is sort of like the the RCA-CTC 20 with the cathode follower after the video det, but uses a demod I have not seen in RCA before, but does seem to have the RCA color ref osc and horz circuit.

old_tv_nut · #**147** 03-27-2024, 01:06 PM

Quote:

Originally Posted by Yamamaya42

This set is sort of like the the RCA-CTC 20 with the cathode follower after the video det, but uses a demod I have not seen in RCA before, but does seem to have the RCA color ref osc and horz circuit.

Interesting. Can you post a schematic of the demods?