Thread: Zenith "coffin"
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Old 08-23-2015, 08:28 PM
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old_tv_nut old_tv_nut is offline
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Join Date: Jul 2004
Location: Rancho Sahuarita
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Doug Harland, a great guy, came over today and spent 8 hours putting all the chassis back in place and connecting everything while I acted as gofer. I'm so glad he did, because this set seems to never have used identical screws for nearly identical functions. I would have spent a week just trying to figure out which screw held what to the cabinet.

First thing, though, was to replace the picture tube with the rebuilt from Scotty and a faceplate from a donor tube. I thought the original faceplate gasket would be Ok, but it had continued oozing gunk and had to be discarded. So, there was a detour to Home Depot to look for some gasket material. We bought several kinds. Here is the stuff that worked out best:

CAM01072 by Wayne Bretl, on Flickr

CAM01073 by Wayne Bretl, on Flickr

You stick the gasket to the tube, then lay on the faceplate, and finally seal it against dust with clear packing tape.

CAM01068 by Wayne Bretl, on Flickr

CAM01077 by Wayne Bretl, on Flickr

In this set, the CRT mounts from the rear. It mounts to a plate behind the bezel, and the plate and CRT have to be removed and dropped in as a unit. The bezel itself is cast zinc.

CAM01082 by Wayne Bretl, on Flickr

CAM01084 by Wayne Bretl, on Flickr

CAM01090 by Wayne Bretl, on Flickr

CAM01093 by Wayne Bretl, on Flickr

Did I mention Doug is a great guy? He stayed 8 hours until everything was connected and could be fired up. Unfortunately, the result was not simple plug and play - some tube sockets appear intermittent; and Doug also suggested testing tubes with a better tube tester to weed out any with grid emission.

The audio amp and tuner do work, if the source switch does.

Currently needing debugging:
Audio selector push buttons switch in the stereo did not want to turn off when "off" was pushed. This is a problem because it also kills the TV sound.Finally got it to turn off after a dozen tries, but probably ready to fail any moment.
Remote control is balky - probably needs retuning, and looks like some old caps are present and may be a problem.
Cannot make cutoff - extinguishing the lines in setup mode leaves a medium bright raster even at minimum brightness setting.
No RF snow; can get audio noise intermittently by playing with tube seating.Tried Deoxit on IF tube sockets, which helped a bit, but still intermittent.
Phono works in manual mode, but won't complete automatic cycle (probably loose belt).
Convergence cloverleaf is broken in two places, currently held together with electrical tape and a tie-wrap. Need to find a replacement if possible.

So, will be investigating tubes and sockets and looking for what's wrong with cutoff.

To thank Doug, I gave him the old CRT (with the hope that the open filaments are a lead wire issue and not actually open) and an interesting Zenith portable (OOF! you call this portable?) from 1980 with continuous VHF and UHF tuners.
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Last edited by old_tv_nut; 08-23-2015 at 09:34 PM.
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