I have a MTS2000 (48 Ch. VHF) that I purchased off ebay last fall. I
recently had it programmed and it worked fine for a day, but now it
displays "F001" when it turns on. I read somewhere that this error
code means the synthesizer is out of lock.

Can someone please tell me what this means, and what it takes to get
it fixed?

Also, when it worked for that one day, I noticed the three buttons on
the side all did the same function, even though I watched the tech
program each button to do something different (backlight, scan on/off,
unprogrammed). Is this a related issue?

Any help at all anyone can provide will be appreciated! Thank You!!