Zenith porthole poor width question....

[Findm-Keepm]

Yes, they used to make a Damper width "cookie" - just plug the damper tube into the cookie, then into the set. In the cookie was just a low-pF cap, around 100pf or so.

I still have a NOS one, from Workman (before they were Workman, they were Dunwell)

http://www.videokarma.org/showpost.p...5&postcount=10

Yours for 5 bucks, postage included.

Cheers,

[old_coot88]

I've done this numerous times. But there's a caveat. It's always been on the standard layout with the damper in series with the B+ line going to the flyback.
I never did it on a pre-standardization layout where the damper is not in series. Your porthole is probably pre-standardization, so it might not work. Probably wouldn't hurt to try, though.

Try a disc cap of around 47pf - 82pf @4KV.

A quick check of the schematic will tell if it's a series layout or not.

(EDIT.) Have you checked the G2 (screengrid) voltage on the H out tube? If it's low it'll cause reduced width and HV.

[Findm-Keepm]

Originally Posted by old_coot88

I've done this numerous times. But there's a caveat. It's always been on the standard layout with the damper in series with the B+ line going to the flyback.
I never did it on a pre-standardization layout where the damper is not in series. Your porthole is probably pre-standardization, so it might not work. Probably wouldn't hurt to try, though.

Try a disc cap of around 47pf - 82pf @4KV.

A quick check of the schematic will tell if it's a series layout or not.

(EDIT.) Have you checked the G2 (screengrid) voltage on the H out tube? If it's low it'll cause reduced width and HV.

Tim,

In your package, along with the cookie, is a bag with some 4KV caps - 100, 130, 160 and 220pf - I was gonna send a PM about them but saw this. I remember we used a 100pf cap in some sets, but I couldn't remember the range of values, and it is probably 47-100pF, so I erred on the wrong (high)side. Hopefully all you need is the cookie.

I see the flyback has been changed. FLy 52 and 53 (thordarson spec'd two flys for the PH's, not sure of Merit or Ram) are different animals, and it wouldn't be the first time someone (not you) changed a Flyback and used the wrong replacement. I have - on a Sony multi-system, and horizontal linearity was off - I adjusted to get it normal, and then had reduced width. So I called Sony, and they confirmed that I had the wrong fly, my mistake, and costly at that. Thankfully the set belonged to a good friend, so I didn't mind the lesson.

On a side, the ETF museum has two flys for Zenith PH's listed on their website...

Cheers,

[bigaudioal]

Originally Posted by Findm-Keepm

Tim,

In your package, along with the cookie, is a bag with some 4KV caps - 100, 130, 160 and 220pf - I was gonna send a PM about them but saw this. I remember we used a 100pf cap in some sets, but I couldn't remember the range of values, and it is probably 47-100pF, so I erred on the wrong (high)side. Hopefully all you need is the cookie.

Has the fly ever been changed? FLy 52 and 53 (thordarson spec'd flys for the PH's) are different animals, and it wouldn't be the first time someone (not you) changed a Flyback and used the wrong replacement. I have - on a Sony multi-system, and horizontal linearity was off - I adjusted to get it normal, and then had reduced width. So I called Sony, and they confirmed that I had the wrong fly, my mistake, and costly at that. Thankfully the set belonged to a good friend, so I didn't mind the lesson.

Cheers,

Fly was replaced with a Merit HVO-11, which listed this chassis (23G22) in it's literature that was in the box with it as an exact replacement.

[Findm-Keepm]

Originally Posted by bigaudioal

Fly was replaced with a Merit HVO-11, which listed this chassis (23G22) in it's literature that was in the box with it as an exact replacement.

What was the original Zenith Fly? It'll start with an "S" - most of the Portholes used the Merit HVO-53, with some windings not used on some models.

[bigaudioal]

Originally Posted by Findm-Keepm

What was the original Zenith Fly? It'll start with an "S" - most of the Portholes used the Merit HVO-53, with some windings not used on some models.

Original flyback was Zenith S-16204. On your attachment it says replacement should be Merit HVO-53 (3). What does the "(3)" indicate? Assuming it is a reference to a footnote. What does the footnote say?

I cross referenced S-16204 to Merit HVO-11. When I got the part, the original paperwork was inside (got it from Moyer in PA). Below are two photos of that paperwork. Showing it is a HVO-11 and showing that it replaces S-16204 out of the 23G22 chassis. So not sure if one is wrong, or both are right, etc??? Interestingly, all the S-numbered Zenith flys on the HVO-11 paperwork cross to the HVO-53 on your paperwork.

Wonder if the HVO-11 was a no good replacement in these models and updated to the HVO-53 later??? Anyone have any insights?

Thx.

[Findm-Keepm]

The (3) indicates that the installer should use the inclosed sheet for instructions. Merit apparently consolidated their flybacks for the PortHoles into one number, unlike Thordarson, who kept it between FLY 52 and 53.

With the Merit HVO-53, there are several sets of windings, and you use only the ones for your set.

Thordarson lists one flyback for your model number, and another flyback for the chassis:

For Chassis 23G22 (and 23G23), use a Fly 53 to replace a S-16204

For Model G2346R (and G2346RZ), use a Fly 52 to replace a S-16566

They show the early PH's as using the 52, and the later chassis using the 53.

Dunno why the discrepancy - anyone have a Zenith 23G22 parts list? Going by model is sketchy, it appears.

Cheers,

[vts1134]

Originally Posted by Findm-Keepm

Yes, they used to make a Damper width "cookie" - just plug the damper tube into the cookie, then into the set. In the cookie was just a low-pF cap, around 100pf or so.

I still have a NOS one, from Workman (before they were Workman, they were Dunwell)

http://www.videokarma.org/showpost.p...5&postcount=10

Yours for 5 bucks, postage included.

Cheers,

Do you happen to have any more of these?

[Findm-Keepm]

Originally Posted by vts1134

Do you happen to have any more of these?

Unfortunately, no. The cookie places a cap of undetermined pf value across two pins of the damper - easy to do without it.

Cheers,

[John Marinello]

A small cap across the width coil will help also, but I agree with the others, there's something you're overlooking.

[vts1134]

Originally Posted by Findm-Keepm

Unfortunately, no. The cookie places a cap of undetermined pf value across two pins of the damper - easy to do without it.

Cheers,

Forgive my ignorance but what two pins and why does that work?

[Findm-Keepm]

Originally Posted by vts1134

Forgive my ignorance but what two pins and why does that work?

Me thinks 3 and 5 - look at the picture - the bottom two pins (holes on the "cookie") are the two pins. I'm not sure, and also not sure of the capacitance, but 47-100pF has been suggested. I mailed it to Tim un-opened, so I didn't have a chance to measure it with my LC Meter. The cap is actually in the little tab that sticks up from the bottom.

Edit: 3 and 5 are the plate and cathode, so it makes sense.

Edit 2: Looking at the schematic, there is a 56pf cap in the yoke. As the yoke was replaced, it may not have the correct values in the yoke, making the cookie do the job of the missing/too low of value cap in the yoke....



Cheers,

[Kamakiri]

Originally Posted by Findm-Keepm

Yes, they used to make a Damper width "cookie" - just plug the damper tube into the cookie, then into the set. In the cookie was just a low-pF cap, around 100pf or so.

I still have a NOS one, from Workman (before they were Workman, they were Dunwell)

http://www.videokarma.org/showpost.p...5&postcount=10

Yours for 5 bucks, postage included.

Cheers,

Well, thanks to the cookie, I now have full width!!!

Picture's off center, but at least it's a full picture!

[Findm-Keepm]

Originally Posted by Kamakiri

Well, thanks to the cookie, I now have full width!!!

Picture's off center, but at least it's a full picture!

Cool! I am Portholio.......sorry Beavis.....

[old_coot88]

Hey cool! That answers sumpthin' I've wondered about for very a long time-- whether or not the damper cap trick will work in a pre-standardization setup (i.e., where the damper is not directly in series with the B+ line to the flyback).