Help troubleshooting SVR2000 reboots

[Jagermeister]

SONY SVR2000
Software is 3.0
Lifetime Sub (thus I'm spending time with it trying to fix it)

Unit worked flawlessly for several months (purchased used w/no obvious upgrades or hacks or even an opened case).

Slowly started rebooting...reboots became more frequent.

I suspected the hard drive and happened to have another HD left over from an earlier upgrade on another SVR2000. Switched out the HDs and the problem continued...with even more frequency. (But it would boot and I could get to menus, etc.)

Then I replaced the power supply.

Plugging in the unit now results in several scenarios, but the most frequent is:
"Your recorder is starting up. Please wait a moment..." Followed by either nothing (hung on that screen), or a momentary flashing screen with pinkish lines then another reboot.

I have also seen it get to the "just a few more seconds" screen...
And even to the "needs to make a daily call" alert...

I have replaced the hard drive cable and wiggled/reseated connections.

I've Googled and searched this forum til my eyes hurt. But seeing as how I've replaced the two things most common to these symptoms, I'm now stuck.

Any and all suggestions would be appreciated!

Thanks,

[funtoupgrade]

Have you tried a clear and delete everything and/or using a fresh image? You can always send it to Sony - based on previous experience cost will be $150+

[Jagermeister]

Since I only paid $160 for unit used...this wouldn't make sense.
And, I have two known good hard drives that I've tried.