Error code u80

usually this means the connection is not 100% or it can not charge or the battery is low ? How old is the unit ? and the regularity of the beeps and if they come from the base or the handset can give a clue try this method:
1. On the handset select Menu, Answer Phone is displayed, press Select .
2. Press CALLS until Settings is displayed, press Select.
3. Press to highlight Ans. & record and press Select.
4. Press to display Message alert and then press
or to select On or Off and select Save.
Saved will be displayed and the annoying machine has now been de-beeped
If you have messages that you have not listened to this can cause beeping . You should try to give the model number and more details that way the answer will be more relevent .

Error c3451 is a warm up error meaning the machine has not yet reached the correct temperature within a specific time. To Reset switch machine off using the switch inside the front door, not the one on the control panel. While holding the UTILITY key down on the control panel switch the machine back on keeping the UTILITY key held down. Eventually a Trouble reset key will be displayed in the LCD screen. Tap that, OK will be displayed then turn off the machine and then turn it back on. This will reset the error code, if the code reoccurs then there will be a problem with the fuser unit in the machine, and this will require replacing.

According to:

bassfisherman60

From the manual
02-57 Fan lock
This code is output when fan locking (over 30 seconds) is detected.
After the error message is displayed, the power turns off.

Perhaps opening the unit with the power unplugged (of course!) and clearing/cleaning the fan would help. It may be that the fan is just clogged with dust/debris.

Try pressing Setting, *,4,5 then Enter.
If the Error code goes away thats great, but if it keeps coming back you may have a more serious prob that would require a serviceman.

Try changing the "command mode" switch on bottom right corner of remote. Setting 3 is the default code. This setting must match the setting in the system setup menu.

door switch may need to be replaced.

Ld unit problem. This code can be very frustrating, as it can be triggered by several things -top right door switches shorting out, toner on the LD unit board, laser synch board problem, bad connection between the BICU and the LD unit, etc.
The bottom line is, if you're not a technician, you will need one to solve this error.
Make sure to always perform the LD pitch adjustment (both 400 and 600dpi) after doing any service to the laser unit.

You must manually hold in the on/off button on the machine itself (NOT on the remote) for approximately 30 seconds. This will shut the unit off. Then you can restart it.

Hi

This is not an error code!
RF CH21 simply refers to a channel that the recorder is set to and is the first channel it will display. For example, there is no CH20. Your recorder is trying to find stations on all its channels from CH21 through to around CH70 and when it gets to the end if it doesn't find any stations, it starts the process again. This will often happen when you first unpack the unit from new until it has been set up.

Firstly, make sure you have a TV antenna connected, even if you use a satelite receiver. If no antenna is connected, your poor old set will keep on searching until you tell it to stop. Incidentally, connecting an antenna will allow the machine to set the clock automatically too. Next, go into the menu options, this is incredibly easy, just follow the on screen prompt.

Find "Tuning Set Up" and make sure that it is not set to auto. If the recorder still continues to show CH21, you will need to switch the unit off from the power socket and leave it for at least 15 minutes before switching back on. Then repeat the above.

I am almost certain you'll fix this, because it sounds as though the machine is doing what it is supposed to. If it still doesn't work please give me a few more details.
Best wishes.....

I get this too, and a little research brought me lots of anecdotes but nothing concrete, but here's was I deduce from the stories...

The unit has an auto-scan feature that periodically checks for new services or channels. Sometimes when it adds one it encounters and error and hangs showing U80. When you're recording it seems the auto-scan doesn't interrupt, so your program will complete. I've had several failures of timed recordings when the unit has stalled before recording was due to start.

Try switching the auto-scan off...

Functions > Others > Display > New service message

Hoepfully that will resolve it, though you will need to manually scan for new services periodically to make sure you don't miss out. At least you'll be on hand if it fails so it won't sit showing U80 for hours!