Zenith Roundie Craigslist Score!

[fsjonsey]

Originally Posted by edison64

The no color issue, is most likely caused by a bad Colorburst crystal some are mounted in a glass tube and sum are mounted in a metal can check the schematic it will show you where it's at. Also I suspect you may have bad or leaky caps in the chroma section yet, most times when you have no color or you can't even tune in color you can usually adjust the peaking coils in the chroma circuit slightly and you should notice rainbow bars start to appear keep going until the rainbow bars lock into true color. It's kind of a down and dirty way to do it but techs used to do it all the time why hook up all the equipment when you have a fiddle stick.... also the no color issue can be caused by a dirty VHF tuner

I replaced the colorburst crystal with one I salvaged from a working, but otherwise worthless touchtone phone. I'm storing this TV in an old office building I'm renting and we literally have piles of old phones lying around, left behind by the newspaper that used to occupy it. Nothing old enough to be valuable of course, 90's clones of ATT 1500 series desk phones made by CorTelco/StarTech in Thailand. After soldering in the crystal from the DTMF keypad, I now have rainbow bars. I'm guessing I'll hit the integrators next, and start looking for any other leaky caps in the chroma section. I also recently picked up a working NTSC vectorscope for next to nothing. Would it be useful for this?

[zeno]

Integrators are disc shaped & have 3 wires. Early ones
were dark brown, later ones tan. Part number stats with 87-
The rest of the number is a paint splotch on them. Color
will match the resistor color code. So if you got orange
paint its an 87-3 yellow 87-4 etc. Sometimes the factory
manual or Sams will show the break down of values. If
not there WAS a page out there that listed them all.
Do not confuse them with 3 legged caps that Zenith used.
They were blue or brown & had a 22- part number.

Odds are the crystal is the wrong freq. so DONT go tweaking.
Pull one out of a junker must be a 3.58###.

73 Zeno

[fsjonsey]

Originally Posted by zeno

Integrators are disc shaped & have 3 wires. Early ones
were dark brown, later ones tan. Part number stats with 87-
The rest of the number is a paint splotch on them. Color
will match the resistor color code. So if you got orange
paint its an 87-3 yellow 87-4 etc. Sometimes the factory
manual or Sams will show the break down of values. If
not there WAS a page out there that listed them all.
Do not confuse them with 3 legged caps that Zenith used.
They were blue or brown & had a 22- part number.

Odds are the crystal is the wrong freq. so DONT go tweaking.
Pull one out of a junker must be a 3.58###.

73 Zeno

DTMF touchtone phones have always used the same 3.58XXX reference crystal as NTSC color TV's. I think Ma Bell did that for a reason, touch tone phones came of age at the same period color tv's did.
Shango's page has the integrator values listed.
http://boxcarcabin.com/integrator.html