Clock and Radio resetting evertime I start?

[fodo91ls]

Everytime I start up my 1991 4 door my clock and radio completely reset.
I can't think of anything I've done to make this happen, I haven't even drove it the last 2-3 months really.

Any ideas?

 

[xusake]

Short ground(-) or power(+).

 

[Future91Sleeper]

Or a bad fuse for the radio memory could be either really