My CTC-16XL Project.

[old_tv_nut]

Vertical linearity errors can affect the convergence at the top or bottom. I think you will "converge" on better performance bit by bit.

[Yamamaya42]

Originally Posted by old_tv_nut

Vertical linearity errors can affect the convergence at the top or bottom. I think you will "converge" on better performance bit by bit.

Yes, I can see how it can, as its fed directly off the cathode of the Vert output via a cap resistor network, (50uf/5.6k) , but I MAY have screwed the pooch a bit here, , I did not replace c4 with an exact 50uf 150v cap like as listed, but with a 56uf 200v.
Will that 6uf throw things off that much?

[old_tv_nut]

Originally Posted by Yamamaya42

Yes, I can see how it can, as its fed directly off the cathode of the Vert output via a cap resistor network, (50uf/5.6k) , but I MAY have screwed the pooch a bit here, , I did not replace c4 with an exact 50uf 150v cap like as listed, but with a 56uf 200v.
Will that 6uf throw things off that much?

My guess is it's not critical because it's not in the feedback loop for the vertical circuit.
Edit: besides, electrolytic tolerance is so wide it would never be designed into a spot that could have a large influence. It generally just needs to be big enough.

[Yamamaya42]

Originally Posted by old_tv_nut

My guess is it's not critical because it's not in the feedback loop for the vertical circuit.
Edit: besides, electrolytic tolerance is so wide it would never be designed into a spot that could have a large influence. It generally just needs to be big enough.

but it does go down (pt 51) to pin 2 on the convergence assy plug, which goes directly to r27 R-G vert lines top, I have always wondered if that 56uf cap was a mistake.

[old_tv_nut]

Originally Posted by Yamamaya42

but it does go down (pt 51) to pin 2 on the convergence assy plug, which goes directly to r27 R-G vert lines top, I have always wondered if that 56uf cap was a mistake.

Again, I think its only job is to be big enough. If you have a spare 50 microfarad of the right voltage rating, you could tack it across C4 to see if even doubling the value does anything.

[old_tv_nut]

If I'm following the circuit correctly, the total resistive load on C4 is about 100 ohms. This corresponds to a cutoff frequency of about 32 Hz, which should be good to carry the 60 Hz sawtooth shown on pin 2 of the convergence connector. Increasing C4 should only make it work better.

[Yamamaya42]

I tweaked the vertical linearity and it mad a minor dif at the top, right top corner is still worst, may never get that perfect.

THIS time I know the placement of the neck parts are right, as i used the GE CTC-15 clone as guide.
https://i.imgur.com/jN1Qj1g.jpg
CTC-16

https://i.imgur.com/kjHeZ2J.jpg

clone

convergence yoke just inside the black area, purity magnets, red area, blue lat, just beyond that.

I may play with it more this weekend, but i NEVER did replace ALL the resistors on the convergence PCB, caps, the selenium device, but not all resistors, and they DO get hammered, this may be a source of trouble..

[old_tv_nut]

Just a note: on my CTC-5 adjusting the V lin could not get it there, but replacing the vertical tubes improved the linearity a little bit and the top convergence quite a bit. No guarantees, but new tubes may be worth a try.

[Yamamaya42]

Originally Posted by old_tv_nut

Just a note: on my CTC-5 adjusting the V lin could not get it there, but replacing the vertical tubes improved the linearity a little bit and the top convergence quite a bit. No guarantees, but new tubes may be worth a try.

easy enough to try, its only 1 tube 6GF7A found a NOS for $$9.75.

unlike the HOT, which the audiophiles have driven up to insane prices...

[Yamamaya42]

While I wait for the NOS 6GF7A to come, next week, or so the tracking says, I have decided to re build the convergence PCB (again), THIS TIME, making sure to replace all resistors that were not replaced before with 5% metal film, and all caps with 5% Panasonic, not sure what caps are in there now, this SHOULD make some dif, I hope, not sure why I skipped the 100 ohm & 180 ohm resisters last time.
Over all cost, $13, costing more for shipping 250 miles from Mouser than the parts, nothing new, but they get here in a day most of the time!

[Yamamaya42]

And shipped.
that's one of the good things about being so close to Mouser, always next day service!

So there will soon be all new parts on the Convergence PCB aside from the coils and Pots.

new parts are.
ECG120 Color TV Convergence Rectifier (on PCB,got in 2019)

ECQ-E6823JF3
ECQ-E2563KFB
ECQ-E2104JF
ECW-FD2W124JQ
PR01000101000JR500 x3
PR01000101800JR500
PR01000102700JR500

No clue if this will make any difference at all, but you never know.

[Yamamaya42]

Definitely a Resistor problem don't know WHY i did not change them when I put the diode pack and other caps in

did a quick check while i had nothing better to do.

1 of the 100 ohms checked at 106 (passable) another at 205 FAIL HARD!!
will wait till Friday night to rebuild the PCB, and the start the convergence process all over again, cause no doubt this will change everything.

If i had $1 for every time i have done the convergence process, I'd be a millionaire! :P

[Yamamaya42]

I really am curious just how much an overall effect this 1 bad resistor can really have.
https://i.imgur.com/exgm9RR.jpg
I know it all interacts with each other, but will that 1 bad resistor being over 100% off cause the center to be off ( static convergence) by being so far off?
I'm very eager to see how much it's going to change.
R220 was within tolerance, as was R218& R217, could not test R219 in circuit, as they are across coils.

[old_tv_nut]

The diodes are meant to keep the center adjustment constant when adjusting left or right, but I don't know how much that is affected when R221 and R220 are so imbalanced. Guess you will find out.

You could test this before you replace R221 - does the center remain constant when you adjust R25 and R28?

[Yamamaya42]

Originally Posted by old_tv_nut

The diodes are meant to keep the center adjustment constant when adjusting left or right, but I don't know how much that is affected when R221 and R220 are so imbalanced. Guess you will find out.

You could test this before you replace R221 - does the center remain constant when you adjust R25 and R28?

It always has to some degree if I remember, in fact, SAMs has doing static convergence a 2nd time in the procedure.
So I guess it WILL be changed by quite a bit!
I'm in for a fun night Friday!
SAMs steps.

static convergence
R-G Vert lines top
R-G Vert lines bottom
R-G Horz lines top
R-G Horz lines bottom
Blue Horz lines top
Blue Horz lines bottom
static convergence a 2nd
Blue Horz lines right
Blue Horz lines left
R-G Vert lines right
R-G Horz lines right
R-G Vert lines left
R-G Horz lines left
go crazy because you have just spent 2+ hours on this going round and round and you have a headache from looking directly at the the screen 3 inches away from your face because your glasses cause chromatic aberration making it even harder to get the silly thing set right! T_T