Sentinel 1U562C (27EP4) Restoration

[Nick]

This was recovered from its original location, from the original owner who has since passed.
It is in very good condition but still needs cleaning and electronic restoration. The SAMS instructions for removing the safety glass do not, or at least do not appear to work with the design of this particular cabinet. Obviously, I would LOVE to not dismount a 27 tube if at all possible.

I would like tips from people who have worked on THIS particular model so I can get accurate information. I had previously posted on other sites/groups without a lot of success with relevant info.

[Yamamaya42]

W/O knowing what was done to it before, it's hard to know what is still needed, the standard always applies, ALL paper caps must always go, including all black beauties etc, and out of tol resistors.
If this has been done, who knows. It is VERY obvious from the screen show that the horz freq is WAY off, so far that the hold can't pull it onto lock.

[kramden66]

Get the set working before you worry about the screen , what is wrong other than the dirt at the bottom of the glass ?
It shows an image , it might be simply recapp , check tubes and resistors and good to go.

You gotta love the dual 5u4 set up , it started the peace sign lol

[Electronic M]

Most makes offered the same chassis in dozens to hundreds of different cabinets (and often different screen sizes) each cabinet having its own model number. 21" sets were more or less the standard from 1953 onwards...Bigger screen sets were typically top of the line luxury models and are rare.

Sentinel wasn't exactly in the top 3 TV makers. You'll be somewhat lucky to find anyone who has serviced that chassis (there's probably a collector or two out there somewhere), but if you find someone who has serviced that model go buy a lottery ticket.

In the first post it sounds like you are having troubles disassembling the set to begin repairs.

If you are having troubles removing the chassis we can give some advice. Generally consoles were built so the chassis is securely mounted, but relatively easy to pull for service (a technician who has done other TVs should be able to figure it out and complete the task in 3-15 minutes).
Back then there were 3 main CRT mounting configurations. Some sets mounted the CRT to the TV chassis only, some mounted the CRT to the cabinet only, others mounted the CRT to both the CRT and cabinet.
If the CRT is mechanically attached (not counting wires that can be unplugged) to the chassis then they have to come out together.
The chassis will be bolted to the cabinet from under the shelf the chassis rests on and possibly behind the pencil box door. Once those bolts are out and the front knobs are off the chassis will be free of the cabinet. CRTs typically bolt to the inside of the front of the cabinet and sometimes there will be a yoke support bolted to the cabinet. There's also a very small chance that there could be mounting hardware for the CRT or chassis hidden behind the safety glass for the CRT that removes from the front.
Given the CRT neck on yours doesn't appear to connect to the chassis you will want to disassemble the front knobs and safety glass, turn the set on its face and remove the chassis and if necessary the CRT facing down. If the CRT and chassis are mechanically connected remove them as a unit, unplug all the wires from the CRT, then mechanically separate the CRT and place it face down till you are ready to reassemble.

Electronic restoration is basically change caps, electrically tubes and resistors and replace bad ones, power up to check opperating, troubleshoot any issue beyond user controls (or that can't be easily attributed to service controls) reassemble and make final adjustments. When troubleshooting you want a schematic for the set Sam's photofact manuals are good for that.
It's time consuming and requires thinking and knowledge. If this is the first tube device you have worked on get a late 40s 5 tube AM tabletop radio and fix that first for practice.

[nasadowsk]

See if you can did up a chassis number - that makes it easy to locate the Sams file, with the schematic, service info, and yes, how to remove the chassis and glass and CRT. 27 inch CRTs are big and kinda dangerous to handle, so be really careful.