Finally joined the club! (CTC-9 content)

[wa2ise]

Originally Posted by miniman82

It's more like a weak signal. I had my RCA jack coming from the LD player going to the 1st vid amp's grid, then switched it to the 2nd and it was worse (lost color).

Usually video amplitudes in a TV set are significantly higher than the 2Vp-p unterminated you'd get from the player. Something like 7Vp-p, so it looking like a weak signal would make sense. So you may not be in that bad of shape.

[leadlike]

I had similar results injecting video into my CTC-9 as well. Since I had an rf modulator laying right next to the tv, I went with that and didn't investigate it further. This may also help with your sync issues, as I have seen pictures fall way out of sync when injecting video.

[miniman82]

Originally Posted by wa2ise

Usually video amplitudes in a TV set are significantly higher than the 2Vp-p unterminated you'd get from the player. Something like 7Vp-p, so it looking like a weak signal would make sense. So you may not be in that bad of shape.

Maybe for this CTC-9, but my Philco set worked great using the same method.


Mark: That first shot with the purple-ish screen was just to see if it would even do anything late at night, so don't pay it any attention. It looks a lot better now, but will likely need a lot of adjustment. I didn't know where the controls were set at that time, so... might have been tint way to one side or something.

[freakaftr8]

Sounds like either you are injecting video into the wrong area, or something's amiss with IF circuits. Is the raster washed out?

[miniman82]

Could be, guess I'll find out here in a little bit.

[wa2ise]

Oh, and another factor to consider: Video is "unipolar", a fancy way to say it matters if it's in phase or 180 degrees out of phase (inverted). Sync tips are the most negative part of the waveform, and white the most positive part. Though, on an RF carrier, sync tip is max amplitude modulation, and white around 10% of that. They did it that way so AGC circuits would have a constant thing to look at, when slaved to the horizontal osc, which should easily find said sync signal. Get it inverted to the way the TV circuit you're trying to inject into, and it's a total mess, no sync, and pretty much unintelligible. Unlike audio, which is "bipolar" in the sense that it doesn't matter (in mono, anyway) which way it is fed to an amp or speaker (in a stereo system, you need to be consistent channel to channel, but otherwise it doesn't matter).

[miniman82]

Not sure what I did, but....



I decided to put all the RF tubes back in and try the tuner again since composite injection was not working out, then low and behold it starts working! Unbelievable, this set is straight outta '59 and works with no resto at all. This is with some coax (not matching x-former) going straight from the DVR to the set.

Vertical looks a bit stretched at the top to me, and height needs adjusting.

Where the heck are the height/width controls on this thing anyway???

[old_coot88]

Originally Posted by miniman82

...Where the heck are the height/width controls on this thing anyway???

Concentric with some front panel controls possibly(?). If you're unable to get enough sweep at the bottom of the screen, look and see if there's an electrolytic to the cathode of the vert. out tube. If it dries up it can cause unsufficient sweep.
Bill(oc)

[old_coot88]

OOPs! Brain fart. There's no electrolytic cap at that location in the CTC-9.

[wa2ise]

Originally Posted by old_coot88

OOPs! Brain fart. There's no electrolytic cap at that location in the CTC-9.

But other caps in the vertical, if leaky, will throw off the linearity and height. Replace all the wax paper caps (if you haven't already) and it should become adjustable.

My old Admiral does have an electrolytic at that location, and yes, it dried out and I had to replace it to get the linearity and height correct.

[miniman82]

All the caps in this set are film, but I'll have a poke at the vertical board anyhow. I searched the interwebz, and found that this set has 'controls inside controls'. In other words, the front panel controls are hollow, hiding another pot inside. I was able to tweak vertical so it fills the screen now, but it's still folding over. Also recentered the horizontal. More in a bit.

[miniman82]

Celebrate our Independence, happy 4th!

Took the chassis with me back home to my folks house, so I could get more in depth with it. There's a scope here, and better tables to work on. Thanks to Mark I now have a good Sams for this set, so things are moving fast now. I found some out of tolerance resistors in the vert board, and replaced some suspect caps in various other parts of the chassis. Still have to order the can caps...

Main thing I'm glad I found was a whacked resistor on the vert board, which came from the height control. It was supposed to be 1.8 meg, but read out at 2.2 meg. I'm betting that's why the height control had needed to be full CW to get the screen to look right. Unsure if it will fix the vert folding as well, we'll have to see after I get the 'lytics swapped out.

More good news: according to Mark's Sencore picture tube tester, I have a like new 21CYP22 in my set!

[miniman82]

Guess I'm talking to myself at this point, but I guess some things never change.


Just thought I'd update everyone: the work I did this past weekend did a lot of good. Vertical now fills the entire screen, the horizontal control now sits more in the center of it's adjustment instead of at an extreme like it had been, and I did a 'ghetto convergence' job tonight using the DVR.

This is what it looks like now. (excuse the crappy cell pics)

It really does look quite good. If I can get Mark to bring along his bar gen next time he stops by, we'll be able to tweak it a lot better than it is now.

[ChrisW6ATV]

That is looking good!

[old_tv_nut]

Progress!