Your "workaround" is totally fascinating to me. It helps me to understand, and who says you can't teach an old dog new tricks, eh?
You hooked up a DVR recorder, and used it's tuner on your TV right? You auto scanned it's tuner, and the TV only locked on channel 3 from the DVR, correct?
Then you had to manually ADD each channel to the TV set, and that's when you got ALL your Channels back on your TV?
If that's the case, then the TV Tuner's BAND has been selected correctly, and you could store ALL channels into your TV manually, yet your TV can only SEE the channel's SYNC PULSE on SOME TV stations but not ALL TV STATIONS.
That's logical analysis...we use that as part of our "tools" to isolate and figure out what is going on with a TV set.
So your auto programming mode will capture the sync pulse on channels 2 to 28, yet 29 to whatever channel numbers are the highest won't capture.
I still think it's a band switching issue, simply because of the fact that at 29, it dumps all stations above that.
Band switching....Let me explain that to you.
You own an AM FM radio ? Do you ever remember your parents or grandparents owning a MULTIBAND RADIO from the 1970's?
It did AM, FM, Shortwave, Fire, Ambulance, Cops....
It was ONE RADIO doing multiple Bands of different frequency channels.
Some were in the VHF and others in the HF and others in the near-UHF bands.
It switched on and off different tuners in the radio to get the channels.
Anyways, TV sets are similar and have always been that way, even back before cable TV became popular.
We had VHF channels and UHF channels. But what you didn't know is that the VHF channels actually had 2 bands of frequencies, and you had to turn on one tuner for low band and another for high band.
Cable....Analog Cable has about 5 Bands making up the entire cable spectrum.
I thought Cable 22 was the END of one band, and 23 was the beginning of another band of Cable, but now I'm wondering if it's 28 is the end.
That would make sense to me if it was....then you'd have a bad tuner that can't tune in Cable 29.
But you manually INSTALLED it....so the tuner is working.
But it doesn't mean the tuner is delivering it's sync pulse to the
Auto programming memory.
And it still points to the tuner -- in a roundabout way. The tuner works....it just isn't delivering the sync to the auto programming's memory to lock onto.
So that's a nice workaround you found.
If you want to spend the money to get the autoprogramming to lock onto channels, you'll need to take apart your TV set, look at the board with the RF coax jacks on it, and find some numbers/letters printed on the board. They're in that yellow box area on this picture --
The code is basically 3 letters/4 numbers long. Yours is AMW or AMV 2432 or something like that.
If you want, you can get that number or even take a picture of the board's numbers and get another main board for it.
A new one is just too much.
That's from a salvaged one...one that broke it's Plasma panel. It's better, less cost. But always verify that part number matches the AWV number on it, if you decide to replace it.
It's the fix for your problem now that we know the problem is not due to some change in Cable's channel delivery.
Believe me....we're stuck with using the box in the FORT.