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-   -   Zenith 5311U / 24MC32 restoration (http://www.videokarma.org/showthread.php?t=268586)

Robert Grant 03-28-2017 08:14 PM

You SO make me want to take on my 5317U again, but I have several things ahead of it.

consoleguy67 03-29-2017 09:03 AM

The dial bulb might be easier to access from the front of the set, by removing the knob.

bandersen 03-29-2017 11:09 AM

I tried that but didn't see any obvious way to get the bulb

Electronic M 03-29-2017 01:05 PM

The socket might be on a slide on-off mounting.

Tom9589 03-29-2017 01:11 PM

You might want to simply pull the VHF tuner. Zeniths (at least the B&W ones) had the VHF tuner mounted with two screws in the cabinet back. I see what looks like rubber grommets on the side of the VHF tuner mounting bracket interfacing with pins on the front face plate.

bandersen 03-30-2017 11:06 AM

I tried getting at it from the front and the knob came apart :(

I think the smoked plastic goes towards then then white paper then the clear plastic then the black ring :scratch2:
https://c1.staticflickr.com/4/3681/3...f6f62b0b_z.jpg

https://c1.staticflickr.com/3/2877/3...2befe006_z.jpg

After a bit of poking around, I realized the bulb holder slid off pretty easily. The holder clip is the ground and the wire clips onto the tuner.

https://c1.staticflickr.com/4/3927/3...12dacee7_z.jpg

https://c1.staticflickr.com/4/3844/3...e3db24ba_z.jpg

It appears to be a #240 bulb - 6.3V @ 0.36A.
Specs: http://www.taillightking.com/images/...0240%20USA.pdf
https://c1.staticflickr.com/4/3927/3...84f5197b_z.jpg

All I had handy was some #1847 (long life #47) and an LED equivalent. They only draw 0.15A and I expect are not as bright.
https://c1.staticflickr.com/3/2873/3...e5d3a22e_z.jpg

It works but is really dim.
https://c1.staticflickr.com/4/3684/3...6438e981_z.jpg

bandersen 03-30-2017 11:12 AM

I noticed the width slowly expands over several minutes when the set is first turned on. No doubt it's the old caps reforming.
https://c1.staticflickr.com/3/2911/3...b6b827bd_z.jpg

https://c1.staticflickr.com/3/2811/3...917d71e4_z.jpg

Zentih sure went cheap on the control door.
https://c1.staticflickr.com/4/3932/3...4c1be926_z.jpg

All the controls appear to be working correctly. Going to put together an order, get some new caps and pull the chassis soon.
https://c1.staticflickr.com/4/3842/3...c57a078c_z.jpg

Findm-Keepm 03-30-2017 11:27 AM

Be careful with that knob - that pot metal "cage" liked to break. I broke the one on our neighbors' Mother-in-Laws set....

https://flic.kr/p/Td3QqK


Cheers,

compucat 03-30-2017 07:04 PM

Quote:

Originally Posted by bandersen (Post 3181560)
I tried getting at it from the front and the knob came apart :(

I think the smoked plastic goes towards then then white paper then the clear plastic then the black ring :scratch2:
https://c1.staticflickr.com/4/3681/3...f6f62b0b_z.jpg

https://c1.staticflickr.com/3/2877/3...2befe006_z.jpg

After a bit of poking around, I realized the bulb holder slid off pretty easily. The holder clip is the ground and the wire clips onto the tuner.

https://c1.staticflickr.com/4/3927/3...12dacee7_z.jpg

https://c1.staticflickr.com/4/3844/3...e3db24ba_z.jpg

It appears to be a #240 bulb - 6.3V @ 0.36A.
Specs: http://www.taillightking.com/images/...0240%20USA.pdf
https://c1.staticflickr.com/4/3927/3...84f5197b_z.jpg

All I had handy was some #1847 (long life #47) and an LED equivalent. They only draw 0.15A and I expect are not as bright.
https://c1.staticflickr.com/3/2873/3...e5d3a22e_z.jpg

It works but is really dim.
https://c1.staticflickr.com/4/3684/3...6438e981_z.jpg

When I restored my 25MC33 Zenith roundie ten years ago now, I too had the tuning knob come apart. The two sections are just lightly crimped together. I had to use some JB Weld to make a more permanent fix. The channel display looks about as bright as mine does with the correct lamp. These are not very bright. I love the metal cabinet. I wish mine were in a metal cabinet. They are more compact and less prone to nicks and scratches. They are great sets and the color is unbeatable when everything is working right.

bandersen 03-30-2017 09:48 PM

Thanks for the info :thmbsp:

I hooked the set up to a converter box and watched a little MeTV tonight. Definitely an improvment over the weak OTA reception! There vertical height is a little lacking and horizontal hold is at one extreme. Also some streaking when text appears. It ill be interesting to see how things change after a recap and weak tubes are replaced.

https://c1.staticflickr.com/3/2930/3...5821941a_z.jpg https://c1.staticflickr.com/4/3894/3...b7e96665_z.jpg

https://c1.staticflickr.com/3/2854/3...fb1e4cf1_z.jpg https://c1.staticflickr.com/3/2898/3...c4a02653_z.jpg

Electronic M 03-31-2017 08:32 AM

Tip on the horizontal hold: the control is a coil, not a pot....So the stop is the knob's pointer hitting the metal tab in the pencil box. To get more range pull the knob out past the point where the pointer hits the stop then turn it some more. The knob should have a hex shaft so you could set it up so the pointer is at mid mech range at the center of the electrical sync range. I can't remember changing caps having much effect on H hold range in Zeniths.

DaveWM 03-31-2017 08:55 AM

biggest issue with Zeniths was the coil forms, the plastic is an issue, other than that they pretty much just work, even with the old caps. Sometimes you may find a cold solder joint on a tube socket, IIRC the video out on later models had this issue, maybe not a prob on the roundies, but it would manifest as a overly bright pic esp near the bottom, solved with a smack of the cabinet. A good socket cleaning of all the tubes will get you 90% of the reliability back, and that's assuming it was stored where corrosion could take hold. Zeniths were built to last, the other plus is the HV was very robust with no flyback issues.

compucat 03-31-2017 11:12 AM

Quote:

Originally Posted by DaveWM (Post 3181607)
biggest issue with Zeniths was the coil forms, the plastic is an issue, other than that they pretty much just work, even with the old caps. Sometimes you may find a cold solder joint on a tube socket, IIRC the video out on later models had this issue, maybe not a prob on the roundies, but it would manifest as a overly bright pic esp near the bottom, solved with a smack of the cabinet. A good socket cleaning of all the tubes will get you 90% of the reliability back, and that's assuming it was stored where corrosion could take hold. Zeniths were built to last, the other plus is the HV was very robust with no flyback issues.

Best of all is no printed wiring, no production shortcuts. You can run a Zenith all day without cooking it to death.

DaveWM 03-31-2017 12:27 PM

Yea the RCA PCB's on high hour sets are frequently smoked.

DavGoodlin 04-02-2017 11:16 AM

Quote:

Originally Posted by DaveWM (Post 3181618)
Yea the RCA PCB's on high hour sets are frequently smoked.

Unfortunately that was also true of clone sets by Philco sylvania magnavox GE Emerson etc. no wonder zenith got such a jump on everyone else🙂


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