Channel lock or revert feature on D-11 100s and others?

[AntAltMike]

A DirecTV commercial dealer who has every category of dealership gave me a few old D11-100s that had been in a sportsbar analog modulated headend. It was my intention to use them for SMATV also.

I'm having problems with two of them. One that I set for CNN 202 keeps switching itself to Fox News 360. The other, which I set to Fox News 360, jumps to Comcast Sports Mid Atlantic 642 and says "no subscription". I have changed them back three or four times each, and have had DirecTV confirm every digit of every registered identification number, to no avail.

Is there some kind of channel lock in these receivers? I remember back with the RCA DRD303s, and maybe with the 100s, if you held down "info" and either the right arrow or the down arrow, a service screen would be accessed that enabled the receiver to be set to return to the selected channel five minutes after anyone had surfed away from it. Is there a similar channel lock-down in these late model receivers?

 

[Hutch1814]

No channel switching like that to my knowledge. Are you sure you don't have a switch going bad? This could cause random channel changes and even a bad line if the voltage drops to low. Or maybe somebody is too close with a remote? Does these receivers change at the same times?

 

[AntAltMike]

No chance any switch failure could cause this. Each receiver consistently elects the same channel (360 on one, 642 on the other) every time, and since the receivers were used in a sportsbar, it had to have had one receiver dedicated to 642.

Someone in another forum has said that there might be a feature called "auto-tune" that might be doing this, but I'm not a DirecTV customer anymore and so I have no hands on familiarity with consumer features that might be responsible for this.

I have had fits with old DISH 2800 headend receivers changing channels. I had one customer with narrow, four foot flourescent tubes that emitted a slightly different frequency white light than the standard 4 foot tubes, and the harmonic of it would be detected as an infrared command. It would only be percveived as a single digit, but after an interval of a few seconds, the receiver would process the flicker as a single digit number and default to the lowest channel in the guide, which was a 2-digit Home Shopping channel. I had to cover all the receivers with tin foil. Eventually, the problem went away. I'm guessing that DISH changed the parameters of pulse sensing such that the flicker didn't satisfy that new parameter.

And not that this could cause the symptom, but I like to remind people of it anyway... those screw in flourescent lights that say LOA (Light of America) used to emit a harmonic that created enough background interference that, after the first time a TV received and responded to a command from a remote, a lot of TVs would not accept