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Re: 1963 zenith 19" space command 300
Quote:
Doug, I had a Zenith 19" set with SC300 in the late '70s. Portable, 19", b&w, and it worked as soon as I got it home (it was a trash day find in my hometown). Couldn't tell if the SC receiver worked, though, as the hand unit was missing. I couldn't figure out how the power tuning was supposed to work, either. Couldn't find a power tuning button or bar anywhere on the front panel; besides, I could turn the channel selector freely by hand, so I'm almost convinced the gear train between it and the drive motor had either been removed by the previous owner or was defective some way (stripped gears, etc). I thought this was rather unusual (a TV with remote power tuning, but no front-panel control of the function); further, the set didn't have a manual channel selector knob to allow operation of the tuner in case the power tuning went bad for any reason. Perhaps that was why it was still possible to turn the front panel channel selector knob manually. BTW, I had a K-series Zenith 23" console TV in the late '60s until 1972. The model number was K2739. No remote, b&w, VHF only. The set also had a 3DG4 LV rectifier, like yours (never could understand or never really knew why they couldn't have used a 5U4 or some other more common tube in this position) and the largest power transformer I ever saw before or since in black-and-white or color sets; the only one I ever saw with cooling fins as well. I have often wondered why other manufacturers didn't pick up on the idea and use fin-cooled transformers in their sets. What was so special about Zenith's finned transformer? Was the idea patented so the other manufacturers couldn't touch it? Also, my Zenith 19" SC300 portable was probably set up to use a three-button remote (the 3 in "three hundred"). Channel up/down, volume/mute and power on/off, I think. I might have had that 19" SC300 set for years if the horizontal output tube hadn't gone gassy after a year. The tube wound up messing up the keyed AGC circuit, which overbiased the IF strip, as I eventually had a picture so weak and washed out I couldn't watch it (contrast control or AGC control had no effect). I was not in a position to get a new tube at that time, so I put it in my basement when it started acting up and bought a new Zenith 12" b&w solid-state portable the next day. That set lasted 22 years without one bit of trouble (except when the detent mechanism of the UHF tuner broke some time in the '80s).
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Jeff, WB8NHV Collecting, restoring and enjoying vintage Zenith radios since 2002 Zenith. Gone, but not forgotten. |
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