View Full Version : Zenith 23ZX38Z - a performer!


jpdylon
11-09-2007, 12:54 AM
I picked this set up from Adam a few weeks ago. He had re-capped the set and it had a fair picture. I thought that due to the old buck rogers dvd the color wasn't all that great.

Upon bringing it home and performing setup adjustments, I could get good grayscale but the white balance was a terrible amber-green. This made the color look awful of course. I had no blue drive, absolutely none

Further inspection turned up a defective blue drive pot. The high side to the center cap was a fixed 10k! although the center to the low side was normal (0-5k). Cleaning did nothing, so since one side of the pot was good, I decided to install a fixed resistor from the high side to the center tap. I calculated the value using the emission of the CRT guns and the current resistance value of the green drive was set at between the mid and high side of the pot. The green was at around 3.8k ohms. Since the blue in this set is a bit weaker than the red and green I figured around 2.5k would be adequate. I had a 3.3k 2 watt, and in parallel with the now fixed 10k value that the pot was at It turned out around 2.2k. This way I had slight control of the blue drive, which allowed my to get perfect white balance.

Now the set has brilliant and beautiful color just as a zenith should. Even off air with no antenna this set pulls in the stations. I even dragged out my old nintendo for some fun. 10 points if you know what game that is...

so what year was this set made? It has only a few transistors in the video, and IF section.

radiotvnut
11-09-2007, 01:09 AM
I'll say you've got a nice set there. My uncle had a Zenith with an identical control panel as this one. I think I remember seeing a date of '66 on his. His went out in the early '80's and sat there until the early '90's when he let me get my 13 year old hands in it. I remember plugging it in and all it had was a raster. Probably an easy fix; but, I hacked it to pieces so I could see how it was made. Since I've aged and matured a few years; I've kicked myself for destroying that set. In fact, the cabinet and CRT is still burried in the basement. The tube was a Chromacolor that was installed in the early '70's.

Oh, I promise not to hack anything else that has potential to be restored.

jpdylon
11-09-2007, 01:23 AM
I did the same thing to a few sets at that age. I had an admiral portable that mysteriously died. It was a cool little set, but I wanted to see how it worked and possibly fix it. Unfortunately I tore it apart and my folks canned it after they saw the mess I made.

Now I take them apart to fix them :yes:

Adam
11-09-2007, 02:03 AM
Looks good:thmbsp: I think it was made in 1967. I had that set for a while, I bought it in a thrift store back when I lived in Berkeley in march of 2002, and then carried it with me when I moved to LA later that year.

sampson159
11-09-2007, 08:36 PM
67-68 we had a zenith dealership in columbus and alot of those were sold.still running service calls over 20 years later on the same sets. they won t die! very good picture-beautiful zenith color at its finest!!

radiotvnut
11-09-2007, 11:37 PM
I also remember a set like this that was sitting in my high school electronics classroom around '94. The back was long gone but the rest was there. The HO tube was glowing red. My teacher kept telling me to take it because he was going to have the custodian put it in the dumpster. I kept putting it off; and, guess what: It wound up in the dumpster. Lesson learned: if someone offers you somehting; don't keep putting them off! There was also a late '60's RCA color console there with a blown off CRT neck. I did rescue the chassis in that one before it got tossed. But, I did bring home several TV's from that class over my two year period in there. I remember one RCA my teacher said I could have; but, I made the mistake of fixing it in class. He wouldn't let me have it after I fixed it. Anything else I got from there quietly got lugged home and fixed.

julianburke
11-17-2007, 07:01 PM
This set was from the 1967-8 model years. When the other Zeniths were $699 and up, this was the "cheapie" model with a $499 price tag. It didn't have the features the others had and had a masonite type of photographed finish cabinet.

Findm-Keepm
11-17-2007, 11:15 PM
If you still need/want the pot, gimme the part number - I have many (new!) Zenith pots, and if I don't have it, then Doug (drh4683) might.

Cheers

jpdylon
11-18-2007, 02:11 AM
THanks Brian. if it comes down to it, I will do that. As long as the blue gun holds up for awhile I should be fine :thmbsp: