Zenith System 3 CRT help

[dieseljeep]

[QUOTE=rtsherrod81;3231220]Hello Zeno,

Thanks again for the information. I have pulled the HV board and found the cap you were referring to. It is a 4.7uF 315V and it has been replaced at least once before as can be seen from below. Someone got a little overzealous with the soldering iron and lifted the trace.

I noticed a label on the board that states "RE MFG IN MEX BY ZENITH" which could explain the repair. Therefore this is not the original HV board.

I need to place an order for another project and I will include this cap. Are there any others I should get as a just in case? Is the installed cap the correct value?

Regards,
Some of the soldering looks a little suspect!
BTW, I read a notice that came with a Zenith rebuilt 9-160 module that they wouldn't accept a module that had a trace blown off due to a lightning strike, as an exchange. It wouldn't meet standards as a U/L approved replacement part.
They never looked at them if they were packed in the box the replacement came in.
I never had one that was damaged that way!

[zeno]

I never saw the lightning warning & I have opened hundreds of them
over the yrs. Never had a dud inspected either.
Zeniths almost never got lightning damage. They use a VERY effective spark gap
between the the cold ground & both sides of the AC line. I have seen many that were burnt but no damage to the set. The points are very close & I would bet it
will ark over at a few hundred volts. Anyhows its on the 9-160 & the black wire
goes to it.

73 Zeno

[rtsherrod81]

Hello Zeno,

I replaced the 4.7uF 315V cap next to the flyback/HV transformer as well as a 1000uF 80V cap that I think is for the degauss circuit since I had one. There was also a 4.7uF 315V cap on the neck board that I replaced for good measure. I'm planning on taking an accounting of the other electrolytic on the board to replace as well.

The picture seems to have improved. It is still a little soft and there is a little color bleed and streaking at times. The picture control (brightness?) is in the upper third of its rotation (CW) to get a good picture. The black level (contrast?) is at its midpoint. "Color Sentry" is off as I think the picture looks worse with it on.

When I turn the picture control beyond the point I have it set to almost max if not max, the picture obviously gets brighter but it blooms. This blooming is also noticeable with the controls set as previously mentioned when bright white text or scene elements are on screen.

I adjusted the focus to get the smallest "dots" on the screen with no signal. The focus control is in the upper quarter of its rotation (CW). I also checked the CRT anode voltage and it is at the 30 kilovolts specified.

Any other steps I can take to try to improve this? What is the "clean & balance you mentioned previously?

There is a Chromacolor II console for $60 about 1.5 hours away that is tempting, but I won't make a move unless this proves to not be worth continuing. Space is limited.

Regards,

Bobby

[rtsherrod81]

Hello Zeno,

I now have a service manual for Zenith Triple Plus Chassis System 3 TVs. This is the CM-130 I mentioned before and is for L-Line. My TV appears to be a M-Line as the model (Service?) number begins with SM and not SL as listed in this manual. The manual does cover the boards that are found in this TV and I will read and study it thoroughly.

If you have a moment, please advise on the clean and balance you mentioned previously. Your help is greatly appreciated.

Regards,

Bobby

[zeno]

Double check the value of that cap, I could swear it was a 10mfd.
The screen shots look pretty good to me.
The color level is a bit high IMHO.
Try this. Run it for a week or two. See if it looks better at higher
brightness & picture levels. Leave the auto color off so you can adjust.
CRT's that havnt been used often get weak & need a wake up period.
Some start unwatchable but will come back nicely.
As far as clean & balance AKA auto restore dont do it unless you
try the above first.

The CC2 set is the easiest set to fix & learn on. Simple design, serviceable,
& truck loads of parts still out there. Wont give you the super brite &
highly detailed pix as a S-3 but in its time the best 25" sets.

73 Zeno
LFOD !