Had a TSU7500/ RFX6500 controlling a Theater for almost a year. (every thing working great) Suddenly it is only controlling 3 of 5 components. When I switch it to IR all 5 components work great. Switch it back to RF & it only controls 3. Tried different rf channels but no luck. I also loaded the original pcf to eliminate the possibility of a coorrupt file. (didn't help either)

Any suggestions?

The only thing I can think of is to check each of your devices to make sure that your RF channel and emitter ID did not somehow get changed.
That happened to me once and I have no idea how it did it.
Don't check your pcf files, check the actual setting on your 7500.
Good luck,
Rick

I have had emitters go bad or come unplugged!

Try a fresh emitter from one of the ports and see if it will control all each device.

Short of checking RF/IR settings for each device, checking emitters/connections I suppose you could have bad output ports.?.?.?

You can check your emitters using a digital camera because the camera's CCD is sensitive to IR. View the emitter using the digital camera's LCD screen and send then a command with the Pronto. You should see the emitter flash if it is working.