yamaha car radio-early 1990's vintage

[crjdc10]

Hello-

I have a yamaha car audio that won't retain the radio presets and the clock starts over at 1:00 every time the radio is shut off. Any ideas on why this is-is there a battery in the radio unit that needs replacing or does there need to be some rewiring.

Thanks in advance,
crj

[crjdc10]

The model number is ycr-220.

Thanks.

[tv.service]

Most likely a back-up capacitor.