2002 Eldorado Bose radio - intermittent no radio, ground

2002 Eldorado Bose

I've searched and found nothing definitive, so thought I'd ask again.

If car sits for 2-3 days without starting the radio will not 'turn on', no display, antenna is not powering up, no sound, no controls. Clock display works all the time. Radio is not losing presets when i disconnect ground.

If I disconnect ground at battery (as had been commented on in several posts), it 'clears' and works perfectly, antenna powers up, etc.

While I can't say with 100% certainty, I THINK I can say that if I drive car every day it doesn't recreate.

But I can't get out and disconnect battery every time I want to play radio. Something isn't 'right'.

It has the 12 disc changer, and I've just removed the cartridge to see if the Changer is somehow or another trying to read the discs or somehow draining battery. But no result to report on that one yet.

I'm not getting a theft/lock code or anything like that.

I haven't had the car very long, so I don't know how old the battery is, but I doubt a few days drain would affect the radio coming or, nor would disconnecting ground 'restore' the battery per se. I assume it has to be a module issue? Or at least something that has to be 'rebooted/cleared'. But that's just a guess.

No current codes. History had a low battery volt code and one EEPROM memory, but don't know how old they were. I'm also going to pick up a multimeter that has right settings to test if there is any battery drain going on.

I didn't know if anyone has seen anything like this before. I can keep chasing, but would like to avoid too many goose chases if someone has some direction for me.

Thanks for any insights.