I had an unusual experience with my remote yesterday.
I own a MX350/MRF250 combo that's been working perfectly for the last year.
When I tried to switch on my system the only thing that came on was the TV that's running on IR only. Checked batteries first. No change.
Then I checked the MRF and the activity light was constantly flashing! I thought the MRF was defective so I tried a new MRF250. Nothing. Tried a different remote. Nada. Nothing I tried made any difference. Bummer.
Today I brought a repeater home to change over to an IR only system after work but gave it one last try and of course the system worked perfectly.
What kind of thing would cause the remote to quit working in RF and then start the next day?

The activity light constantly flashing indicates RF interference. While that exists, your remote will not work well or may not work at all. Not a bad remote or MRF, but the interference is coming from somewhere. If you get that taken care of, you will be back to normal.

I assume you have the dial on the MRF-250 set to any number except 0?
If so, it's hard to say what might have caused the temporary interference. Could be a remote stuck on or another device transmitting the same frequency in your house or a neighbors. For example, I had a similar problem where someone placed a heavy object on a remote located in the household that pressed a button and caused continuous RF transmission. Also I've noticed that the MRF-250 will hang up occasionally and needs to be power cycled.

I once had a pump motor in a bird bath behind my living room cause RF issues. Let's just say they stopped the second I unplugged the pump.

I've unplugged everything to the point of having nothing but the MRF powered up.
The interference must be coming from outside my duplex. After a night of normal functioning I came home and the interference is back.
I guess I'll have to go back to IR only.
I really like the remotes, but the RF performance is killing me with clients and now at home!

P.S. Tom I've been selling and installing the remotes for years now and I've had too much experence with RF troubleshooting. I've heard that sometimes electrical transformers will start spitting out RF noise on the pole. Will I have to shoot the tranformer?

Power pole issues do come up. I'm a ham radio operator, and transformer problems or insulator problems on poles can cause radio frequency interference for hams. You can call the utility company out if you can sniff the problem and show them that it's really an issue.

Here's an example of interference that happened to me last night. I have a MRF-300 in my viewing room and the antenna module is in the adjacent room. I turned on my floor standing room cooling fan and discovered that my MX-3000 RF response was hit and miss. Turned off the fan and I was back to 100% response. The fan is a Black & Decker with electronic control. My conclusion is that interference can come from most any appliance or device.

I think Julie had a cordless phone goofing up her remote commands. You never know, you know?

Mark I think your problem is altitude related. You need to hold the remote less than 6ft from the floor. JK......Really what you should do is go to your breaker box and shut the whole house down the run an ext cord to your neighbors outlet outside to the MRF. Then see if it is still lit. If yes, then pull your neigbors meter and throw it in the woods. If no then turn each breaker back on until the offender surfaces then unplug it and go throw it in the woods.