Quote:
Originally Posted by joe111671
It's been a long time, but that's how I remember it and the set came out fine. In your case, I wouldn't use any of the settings of the corrupt chip that you had messed with. John, does that sound right?
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That's correct. I was an RCA ASC and we did it by the book, which was a new eeprom and a full chassis and tuner alignment. Any eeprom failure meant *something* was corrupt in the eeprom, and it usually affected a bunch of areas. I never used any data in the original eeeprom.
Back when a lot of these TVs were used on antennas or cable systems with no cable box, some servicers would replace the eeproms either with a new RCA chip or a "preprogrammed" one, and have issues with certain bands being snowy.
As an RCA ASC, we had to buy the TAG001 tuner alignment generator, which made alignments a snap. Basically it's a frequency agile modulator that had RCA video inputs. It worked on the RCA remote so if you punched in channel 2 on the remote, the TV would go to channel 2 and the TAG would display a channel two and modulate your video source on channel 2. Punch in channel 6, and both the TV and TAG would go th channel 6 at the same time.
Back when these were new, I was doing a ton of these and I could do a full eeprom alignment in about 10 minutes, including the tuner. These tuners covered 125 channels but had only 19 specific channels which had to be aligned/peaked. Tuner alignment only required a DMM to monitor the AGC line, and truth be told, you could do it by eye just watching the screen for signal level. The TAG generator had four attenuator switches so as each band's target channel was adjusted, I would just drop the signal and peak it for no snow. No DMM needed.
If the TV is only going to be used on channel 3 or 4, only one alignment point needs to be adjusted (three parameters for each alignment point IIRC) to cover low band VHF. Full alignment is no longer needed.
John