This project took awhile...12 years to be exact! I wanted to completely restore one of the early, great Philco chassis' to it's original beauty of operation.
I first began servicing NTSC sets in 1958, at the age of ten. While my parents always owned Zenith, even from an early age I began to appreciate Philco's design and construction techniques. They produced a picture most-like the legendary Conrac monitors in service at television studios of the day. Well, this model was one of their best. It paralleled the great radios they built ten years earlier, was easy to service, and the results were top-drawer.
Just from this crude mini-DV recording, the pro will spot the extremely wide bandwidth, full DC restoration, precise AGC and sync clamping and full NTSC interlace, under widely varying modulation conditions. Not being an intercarrier set, the audio is also superb. It took them four IF amps to get the 26Mhz strip widened and high-gain, but that left so much adjustment latitude that bandwidth was easy!
I have to admit that I lucked out! The original 12LP4 CRT was new-perfect. Healthy, slow lighting orange heater, emission out the top, aquedag coating intact, and burn-free. So were the yoke and flyback in near-original shape. The tuner was the Standard "strip" tuner of the J series...one of the best ever built, and not their early wafer tuner, which after 60 years can be a problem.
I got the set working in 1999, after only a couple days during which I replaced all the original oil caps (they had the right idea, but these just didn't last) and reformed all the major electrolytics. Then, it got kinda shelved for a decade while I searched for a replacement cabinet and got up the nerve to tackle my first 26Mc IF alignment in nearly 50 years. I even bought and serviced an Eico sweep and marker generator and B&K Analyst!
Once the cabinet was secured, I sat down to "do it." Well, in strong light, I observed that one adjustment slug was not at the original position, as shown by the broken glyptol seal. It was a trap at the tuner output. These were often changed by repairmen in an effort to eliminate early color transmission problems. I carefully returned it to the end of the glyptol and immediately, all smearing and telltale ringing as the fine tuning was rotated were gone. Color bars were then tried and, as I suspected, Philco had it covered. Not a hint of a problem! I swept it and the desired inverse-saddle appeared at once...opposite of how the best-looking TV transmitters were tuned for sixty years! All that apprehension and the job took four minutes!
All that remained then was to install a small fan above the HV cage to pull heat from it and the chassis below, out the top rear of the new cabinet, and to restore and polish the plexiglass faceplate.
The only mod made to the chassis was the addition of high-impedance vertical and horizontal retrace blanking to prevent both retrace lines and to accentuate detail in the critical dark gray areas of the picture...those lost forever to us by LCD, Plasma, and the awful HDTV system we are now forced to watch.
This is one of the sets that sold television to America. While that may have been less than a blessing in the long run, as always (until the printed circuit and American Meltdown of the late 50's) Philco did it right.
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7:11
1965 Zenith Roundie playing "Honey-Mousers"by wurly11001,480 views
Amazing job, I'm speechless.
cazzozzo 3 months ago
Nice set I have a 1950 set that looks very simmalar
avaelectronics 3 months ago