Wow, just like you said: I bent the connector housing on the floating board back to being straight, and the error went away.
Thanks so much.
I also ordered a USD$30 LCD screen from Aliexpress to replace the one it has, which was suffering from a few dead rows.
Total spend so far for a perfectly working DSP-2000 = $0.99 for the "not working" DSP-2000 on Ebay, + shipping, + $30 LCD screen
I upgraded the firmware to the latest version too.
With the cover removed, if you turn the rotary switch to a position only available with the cover removed, it becomes a Smart Remote.
The Smart Remote status is displayed on the LCD instead of Smart remote LEDs.
I have replaced some of the CR2450 batteries, but just soldering onto cheap $6 Energizer batteries from the hardware store means they heat up a lot during the process -- that may make them leak over time perhaps. I am going to experiment with soldering using a low temperature solder (Chipqick SMD1 kit from element14 melting point 85 deg C but is actually an SMD removal product, so failing that: Chipqick SMDIN100 which an actual solder, Indium with melting point 143C). That is more economical than buying lots of tabbed coin cells.
If you need any spare parts or help let me know. I have posted all I know here.
https://drive.google.com/open?id=1yVDiAwMg3zo4jIwa44o64lHkammTZvIUI would really love a copy of the service manual if any has one...