Source or info for vertical integrators

[JCFitz]

Looks like I have yet another issue with the 1956 Admiral 20Y4E Super Cascode tv.Everything is pointing at the vertical integrator being my cause of critical and unstable vertical hold. Horizontal sync is fine. I scoped it last night and Sams shows 2 waveforms at the output of the integrator one normal operation (was low in amplititude but there suspect most is pickup of the oscillator circuit) 2nd is grounding the plate of the vertical oscillator to disable it (supposed to be 15v p-p at output of the integrator was extremely low at about 3v pp) Also I measure around 620k across the integrator. Shouldn't it be lower than that?

Anyway. It is an Admiral pt no. 63C9-1 which I doubt I will find anywhere. It crosses to a Centralab PCT-104 or Sprague 103C12.No internal schematic is shown on the Sams and I have yet to come up with anything googling it.

Does anyone know where I might find either one of these or a reference to the internal component values ?

[Tim]

PM me with your e-mail address and I'll send you the Centralab Couplate catalog that includes the PC-104 Vertical Integrator info.

[wa2ise]

I have the 1956 Beitman, and the Admiral 20Y4EF, shows the set using a 6BH8 triode as the vert osc, and shows the innards of an integrator 63C9-1 on the circuit board layout, which looks like yours. Diagram says M402.

Looks it should measure about 38K, not 620K.

[Eric H]

I wonder just how critical these integrators are?

I have two sets that I know have bad integrators, one has a broken center lead, the other measures completely out of spec yet both have stable vertical.

I forgot to fix the one with the broken lead (Sylvania) and put the set back together, touching it to where it was supposed to go only made a slight shift in the picture anyhow so I didn't feel like taking it apart again, the other one (Wilcox-Gay) i just left alone (i had made up one from parts and tacked it on but removed it).

I know you can build them out of individual components (most older sets have them made that way anyhow, always 8200 ohm resistors too.) but I was wondering what exactly are they supposed to do?
Maybe in the two cases here they were working enough to pass sync but were lacking in some other way?

Seems like you would have no sync at all without them?

[wa2ise]

Originally Posted by Eric H

I wonder just how critical these integrators are?



I forgot to fix the one with the broken lead (Sylvania) and put the set back together, touching it to where it was supposed to go only made a slight shift in the picture anyhow so I didn't feel like taking it apart again, the other one (Wilcox-Gay) i just left alone (i had made up one from parts and tacked it on but removed it).

I know you can build them out of individual components (most older sets have them made that way anyhow, always 8200 ohm resistors too.) but I was wondering what exactly are they supposed to do?
Maybe in the two cases here they were working enough to pass sync but were lacking in some other way?

One of the goals of a vertical integrator is to get vertical deflection such that you do not get line pairing of the scan lines from one field to the next. Analog NTSC TV used interlaced scanning, and one field's lines should get "written" on the CRT faceplate phospor halfway between the lines of the other field. The integrator ties to remove the effects of the horizontal sync pulses. One vertical sync pulse starts at the beginning of a horizontal line, next field, it starts halfway into a horizontal line. If the vertical oscillator gets too much influence from the horizontal, the scan lines will end up on top of each other (pairing) instead of halfway between, and the picture loses vertical resolution. The integrator filters out the horizontal pulses. A bad integrator will probably give you pairing. The picture should look better if you fix it.

[JCFitz]

Originally Posted by wa2ise

I have the 1956 Beitman, and the Admiral 20Y4EF, shows the set using a 6BH8 triode as the vert osc, and shows the innards of an integrator 63C9-1 on the circuit board layout, which looks like yours. Diagram says M402.

Looks it should measure about 38K, not 620K.

Thanks. I thought one of the resistors might be open inside from comparing to other schematics in books of vertical integrators. 620k is way too high.

Can I ask you one more question on this chassis since you have the Beitman's? What voltages and pp are shown on the HO tube grid and screen grid ? I replaced a bad drive trimmer that maxed out at 400 pf (half the stated max value). The new one goes up to over 800pf and it too is maxed out to stop the plate from glowing.Couldn't eliminate it with the other trimmer. Trying to figure out what is amiss that causes me to have to max out the trimmer to just barely get enough drive (if I have enough) instead of getting a drive line like I would expect with a trimmer maxed out.

Sams says -28 on the grid and 80vpp which I get when I got the line voltage set to give me the rated 265v B+ but Sams quotes 145 v for the screen grid. I'm getting more like 185-190v.The screen grid resistors are new. The originals were burnt to a crisp and the 8200 measured way low.

[wa2ise]

Originally Posted by JCFitz

Can I ask you one more question on this chassis since you have the Beitman's? What voltages and pp are shown on the HO tube grid and screen grid ?

Beitman's says -30V on G1 of the 6CU6 horiz output tube, and it shows a triangle wave of 145V (I presume that's peak to peak, it doesn't say).

I replaced a bad drive trimmer that maxed out at 400 pf (half the stated max value). The new one goes up to over 800pf and it too is maxed out to stop the plate from glowing.Couldn't eliminate it with the other trimmer. Trying to figure out what is amiss that causes me to have to max out the trimmer to just barely get enough drive (if I have enough) instead of getting a drive line like I would expect with a trimmer maxed out.

The Beitman's diagram has in series a 0.0047uF cap with that trimmer. A note says "may be used in some models". If your set has it, maybe it's bad?

Sams says -28 on the grid and 80vpp which I get when I got the line voltage set to give me the rated 265v B+ but Sams quotes 145 v for the screen grid. I'm getting more like 185-190v.The screen grid resistors are new. The originals were burnt to a crisp and the 8200 measured way low.

Beitman's has 145V for the screen grid. It says B+ is 270V, so yours is close enough I'd think. Boosted B+ is 520V, terminal 8 of the flyback transformer (don't know it that is marked, though).

[JCFitz]

Originally Posted by wa2ise

Beitman's says -30V on G1 of the 6CU6 horiz output tube, and it shows a triangle wave of 145V (I presume that's peak to peak, it doesn't say).


The Beitman's diagram has in series a 0.0047uF cap with that trimmer. A note says "may be used in some models". If your set has it, maybe it's bad?



Beitman's has 145V for the screen grid. It says B+ is 270V, so yours is close enough I'd think. Boosted B+ is 520V, terminal 8 of the flyback transformer (don't know it that is marked, though).

No .0047uF cap in this one.I think I'm a little low on horizontal coming out of the oscillator so I'll look there. The plate voltage on the 2nd triode is a little low at 142 vs 145 on the Sams not really alarming though.

[cbenham]

Originally Posted by Eric H

I know you can build them out of individual components (most older sets have them made that way anyhow, always 8200 ohm resistors too.) but I was wondering what exactly are they supposed to do?

The integrater circuit integrates the very narrow Horizontal pulses in the sync signal to broad vertical pulses.

See the explanation on the page attached from this very old TV book...
Cliff

[Phil Nelson]

I heard somewhere that the capacitors in (at least some) integrators are actually paper caps. My limited experience is that they're more reliable than ordinary paper caps, but they can fail.

Does anyone know what the caps inside are made of?

Just curious,

Phil Nelson

[wa2ise]

Originally Posted by JCFitz

I think I'm a little low on horizontal coming out of the oscillator so I'll look there. The plate voltage on the 2nd triode is a little low at 142 vs 145 on the Sams not really alarming though.

Beitman's says 165V on that 2nd triode plate (the driver) pin 6. 11V on both cathodes, -11V on the driver grid, pin 7, and 4V on the other grid, pin 2, 250V on the other plate, pin 1. It also says 55V waveform (seen in the upper left corner of my earlier attachment) on pin 1.

Does anyone know what the caps inside are made of?

Phil Nelson

I figured that they're ceramic, with metalization on both sides opposite each other to make a capacitor, and on other parts of the rectangular slab of ceramic they deposited carbon traces for resistors

[cbenham]

Originally Posted by Phil Nelson

I heard somewhere that the capacitors in (at least some) integrators are actually paper caps. My limited experience is that they're more reliable than ordinary paper caps, but they can fail.

Does anyone know what the caps inside are made of?

Just curious,

Phil Nelson

I have seen really old wax-paper caps and later, ceramic caps in slightly newer sets [mid 50s] but by then the little molded ceramic network was in use too. I usually use new plastic mylar caps and 2% carbon film 1/2 watt resistors to build my own replacements. I did that to the one in my 630 and it works great.

Cliff