Help Identify My New Zenith

[TinCanAlley]

Originally Posted by zeno

Without going into much detail.........
I always pulled the IF jack when doing a grey scale if it was easy.
This gives a totaly dead raster or line.
Pin 9 is focus so not to worry for now. Pins 5-6-13 are G-2 and
may concern you. Measure at the chassis unless you have a test socket.
The only thing in the socket is spark gaps & 1 K resistors.
they do go bad but usually the focus pin from too much focus voltage
or constant high humditity.....
I highly recomend a rebuilt Fluke meter
off e-by. Got them for both sons & do more then the cheapo
meters. Also can drop them, hit people with it etc & will keep
running. Just be sure it goes to 1 KV DC. They run abt $75
but will last your life. Beond 1 KV you need an HV probe..........

73 Zeno

Do you mean 5,4 and 13? The leads to the socket go though to under the chassis. Do they have test points somewhere on the top of the chassis?

I'll see about unplugging the IF lead and check for a rebuilt Fluke or borrow my brother's. Will still get one, but don't want to wait any longer than necessary to get this puppy up and running. The safety caps will be here Tuesday.

Thanks

[andy]

...

[TinCanAlley]

Originally Posted by andy

4, 5, and 13 are the G2s. You won't be able to fit a meter probe in the socket (don't force it, or you'll ruin the socket). The exact voltage isn't important, but they should all cover roughly the same range when adjusting the corresponding G2 control. They should max out around 900v or so. You'll probably have to measure it from under the chassis.

Thanks. I see they run under the chassis to the G2 pots. I will have to put the set on its side, take the base off, take the underside chassis cover off and leave it like that so I can measure the voltage. Since each one of those leads has more than 500V, I'll have to get my hands on a DMM that can do more than mine.

Is there any danger of a short if I accidentally touch any other lead on the G2 pot or the body of it?

Thanks

[zeno]

Originally Posted by TinCanAlley

Thanks. I see they run under the chassis to the G2 pots. I will have to put the set on its side, take the base off, take the underside chassis cover off and leave it like that so I can measure the voltage. Since each one of those leads has more than 500V, I'll have to get my hands on a DMM that can do more than mine.

Is there any danger of a short if I accidentally touch any other lead on the G2 pot or the body of it?

Thanks

Sorry about the pin mix up
You could slip & put 800-900 V where it doesnt belong so
use a clip lead to play it safe. Slip happens when working in
dark, awkward conditions. When doing it for a living you just
measure away for the sake of speed but you can relax &
take your time. Less mistakes that way.
BTW when working on its side the purity will usualy be bad,
just ignore it.

73 Zeno

[TinCanAlley]

Okay, got the safety caps in and double checked I didn't mess something up while cleaning. Made sure I didn't dislodge any transistors or cause any two or more leads to touch each other. All was well upon start up.

I used clip on leads on the center post of the G2 pots (that's the lead to the CRT socket). I measured each G2 to be between 426 with pot down and 752 with pot up. So I'm assuming those numbers are good.

Next...as I'm typing the set is warming up so I can try the grayscale again. Hopefully I can get the red raster line this time.

Wish me luck.

[TinCanAlley]

Well I managed to get a dim red raster line and adjusted the blue and green to the same level (really the best I could guess as a dim line looks like a dim line). From there I got a b&w image and adjusted the taps to a screen that had just a very slight blue tint to it. Moving the tap lower made the screen a bit red. So I put it back. Should I try moving the blue G2 down a bit?

The convergence is a bit messed up. I'll have to wait until Thursday when I get the pattern generator. I'll use it to converge the center dot, then do a purity and finally do a convergence. Hopefully all will go well.

I do have a question about picture height and width. On my other CC2 it has height and width adjustments. On this one I don't see them and they aren't listed in the SM. The overscan is a bit too much and I'd like to reduce in all directions.

Thanks.

[TinCanAlley]

I got my hands on a Minwax mahogany stain scratch cover up stick. As long as you don't get too close or shine a light directly on the surface, you'll hardly notice if at all. My next step is to get all the off white color cards from Lowes and see if I can find a white the matches close enough. Can't exactly take the set to them for color matching.

[TinCanAlley]

The set is making itself at home.

[andy]

...

[zeno]

Maybe I missed it but whats the chassis ## ?

IIRC the vert controls are on the module with little extention
shafts. If there is a large adjustment needed UNLESS the pot has
a bad spot or someone messed with it it HAS a problem.
You should do the vert next, it may cause more damage.
BTW your voltages are OK, its not unusual to tweek the
grey scale a little especialy an old set.
Be sure when doing your doing the final set-up the set has
run a few hours & is nice & warm.

73 Zeno

[TinCanAlley]

Originally Posted by zeno

Maybe I missed it but whats the chassis ## ?

IIRC the vert controls are on the module with little extention
shafts. If there is a large adjustment needed UNLESS the pot has
a bad spot or someone messed with it it HAS a problem.
You should do the vert next, it may cause more damage.
BTW your voltages are OK, its not unusual to tweek the
grey scale a little especialy an old set.
Be sure when doing your doing the final set-up the set has
run a few hours & is nice & warm.

73 Zeno

It's a 25EC58. The reason I want to adjust the sizing is I noticed that what I see on my 18 CC2 in the upper part of the screen is about 1" closer to the top or actually off the screen.

I got this set from someone that got it from a shop of sorts. It looks like they messed with things as I just noticed the deflection yoke clamp wasn't tightened down.

[TinCanAlley]

Originally Posted by andy

You will probably need to readjust the G2s after changing the drive taps since they interact. Always finish with by adjusting the G2s for a dim white service line.

There is definitely a vertical size adjustment, but there might not be a width adjustment. It's not unusual (and considered normal) for there to be up to 20% horizontal over scan. Be sure to adjust the size before the convergence since they do interact.

I'm getting the CRT tester and the pattern generator today, so I can start the process of making sure the static convergence, purity and convergence is correct. Then I'll tackle the G2s again. I figure it'll take a few attempts. My other CC2 was a bit easier. It had a main G2 that I set for dim raster and then adjusted the color G2s with a b&w image. Didn't have the taps to deal with.

I'll looked over the SM again and found that on the vertical board there are two pots. One for size and one for linearity. Not sure what the second one does. Is it important to adjust that one while adjusting the size pot?

I didn't find a horizontal size adjustment.

[NowhereMan 1966]

Originally Posted by Jeffhs

I just watched an episode of Kojak (on MeTV) in which a Zenith Avanti color TV like yours was featured in an apartment. However, your Avanti is in excellent shape for being well over 35 years old. The white pedestal base on these sets often turns yellow with age, but yours seems to have escaped that, at least for now. Congratulations on finding one of these in nearly pristine condition.

I agree that the 4-lead safety capacitors should be tested and replaced if necessary, before the TV is used any length of time. I don't know how much you know about color-TV high-voltage systems, but one serious problem that can occur with them if the safety capacitor(s) should short or open is that the CRT second-anode voltage will go sky-high, often causing the neck to shear off the tube. I don't know what type of CRT the Avantis used, but if they are rare (or at least difficult to find), it is best to correct any HV problems before the original tube is damaged or destroyed.

Good luck. Your Avanti should give you many years of good service, once the HV safety capacitor(s) are replaced and the area around the second-anode connector is cleaned well. Dirt, dust or other foreign matter in that area of the CRT, especially under the rubber 2nd-anode cap, can and often does cause HV arcing, which in solid-state TVs can destroy parts such as the HV tripler. These may well be NLA (no longer available) for this set at this late date, so anything you can do to keep the original in good shape will be worth the effort.

I just saw that episode too! BTW, my best friend had an Avanti (the space age looking) Zenith when we were in high school.

[Findm-Keepm]

Originally Posted by TinCanAlley

I got my hands on a Minwax mahogany stain scratch cover up stick. As long as you don't get too close or shine a light directly on the surface, you'll hardly notice if at all. My next step is to get all the off white color cards from Lowes and see if I can find a white the matches close enough. Can't exactly take the set to them for color matching.

Before you paint, look at the retrobrite project - they use chemicals to brighten yellowed plastics:

http://retr0bright.wikispaces.com/
I'm happy with the results on an old RCA plastic radio from the 70's. Best use of peroxide since gold recovery.....

Cheers,

[TinCanAlley]

Originally Posted by Findm-Keepm

Before you paint, look at the retrobrite project - they use chemicals to brighten yellowed plastics:

http://retr0bright.wikispaces.com/
I'm happy with the results on an old RCA plastic radio from the 70's. Best use of peroxide since gold recovery.....

Cheers,

I was only planning on painting the chipped areas of the paint. Wasn't planning on painting the plastic stand. I do like the site you gave. I'm going to make the paste and test it on the back side of the stand and see how it works. If it works well, I'll make enough to cover the entire stand. And to think I was trying to figure out how to submerge the darn thing and how much that would cost. Glad to find a formula that makes a gel. Should cost about $40 to make.

Thanks!