I have Comcast cable. Recently, the remote control - 'Comcast On Demand Custom 3-Device Universal Remote Control' - stopped functioning partially. We could still change channels, but it wouldn't turn the TV on & off, change the volume, or turn on the DVD or VCR hooked up to the system.

We checked, & all batteries were fine. Changed them anyway, in the remote! Comcast first said that we'd lost the signal, & needed to input the code again. Couldn't find the code - not the numbers listed. When a repairman finally arrived, he said we needed an RF modulator.

I don't see why we need an RF modulator, if this setup has been working fine for years! He didn't seem to know why the remote control wasn't working. Any suggestions?

Currently, the cable connects to the Cable box (Motorola DCT700), which connects to our VCR (Emerson VCR988). The VCR connects to the TV (Sylvania SST4192). These are all connected with the thick black round cables (sorry don't know correct term). The DVD (Magnavox MSD124) is connected to the TV w/ the 3-colored connectors.

We can't use the DVD or the VCR now. What happened! :confused:

You don't need aModulator since TV has 3 cable input.
If Batteries were changed slowly or button pressed while batteries out, you likely lost remote control codes and needs to be reentered. It will not lose the Comcast code.

Thank you for your response. It does appear that the remote control code was lost. We tried the listed codes, & none of them worked. Spent over an hour 'seeking' the code. Very frustrating!

The repairman was totally off! Said our DVD was at fault (?! ).

We will persevere!

The code search can take 200 presses, more on some remotes. You can get going so fast and pass the one that works, some you can press channel down to go back a code, then enter.
Verify you are going into code learn mode and codes for correct device and manufacturer.
If TV doesn't learn, try next item(VCR), If none program you may be missing a step or unit is defective.
Good Luck

Found this, may help if instructions were for a different model:
Remotes