stereo question

[76bonanza]

Yesterday I was wiring my alternator and did not disconect the batery, I touched the positive to the block and it sparked. I hooked it all up and it seemed all ok.

BUT I noticed just my radio stations reset. the time was ok. I Reset the stations seems ok now.

BUT I also have a Cd changer fm type. It has power at the changer. I reset it and it cycles thru the cds no problem. Checked all the wires all have a good 12volts. But the control unit in the dash will not power on all connections are good.

My question is could I have wiped the preset stations and not the time?

Also do you think I smoked the control unit and not the changer?

Thanks for any help.