My CTC-16XL Project.

[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

[Yamamaya42]

Got the new parts today as expected, and it never ceases to amaze me how much resistors have advanced since the 60s, I mean they ARE 1w but they are ¼ the size of what they are replacing, and will most likely last much longer!

WOW, just wow!

[dtvmcdonald]

"¼ the size of what they are replacing, and will most likely last much longer!"

Also, a certain bridge to Brooklyn is 1/4 the size it used to be, but carries as much traffic.

If they are that much smaller, they will run that much hotter. Its the laws of physics.

Because they are hotter they may well not last any longer than the old ones.

But worse ... being hotter, they are more likely to damage other parts close to them.
You need to space the new ones out so that they are centered exactly where the old
one was. Even then the spot directly above them gets hotter.

In general, if an old resistor is rated more than 1/2 watt, I make sure the new one
is roughly the same size, even if much higher rated. If the old one was 1/2 watt,
I just check and make sure the new one is running at less than 1/3 its rating, and is long enough to take the peak voltage across it. Of course lots of old 1/2 watt carbon resistors were run at far less than 1/2 watt.

[Yamamaya42]

https://www.mouser.com/datasheet/2/4...03-1762580.pdf

It's unlikely that heat will be an issue with these at all, I chose “power resistors” vs standard ones, and the rated voltage @ 350 is far beyond the original carbon composites, and even if they do run a bit warmer, they are going to be mounted raised a bit & not flush like the old ones were.

[Yamamaya42]

Another thing to keep in mind, the newer ones are much better in dissipating heat than the old carbon composite resistors, and thus are substantially smaller.
I can't find by what factor exactly they have improved, but it seems by being made of better materials, IE glass/ ceramic cores vs doped carbon, and thinner insulation ETC, what physical size resistors that were approximately 1W now are 3w, so on and so forth, this is how they have progressed things.

[Yamamaya42]

i put in one new resistor , the one that was worst off, just to see what difference it would make.
https://i.imgur.com/joQpdzx.jpg


and you can see on the thermal scan how much cooler it runs vs the old carbon ones.

also it DID change the center.
https://i.imgur.com/S6HMTfL.jpg