Pioneer LC-V300 LaserKaraoke Autochanger

[MIPS]

I always wondered if someone was crazy enough to make a multi-disc changer for laserdiscs. Turns out Pioneer was.

This four foot tall 150+ pound monster can hold 72 double sided laserdiscs which are played on a vertically moving double laser (two players sharing the same spindle) player.
Someone uploaded a clip on youtube of my unit being advertised by Pioneer. https://www.youtube.com/watch?v=c8GADxWKEKM
There were two of them sitting at a recycling center in Seattle. They wanted $350 each, presumably because one was recently listed on ebay for $637 but failed to sell. I wasn't about to blow $700USD on them for the reasons below but was able to negotiate down to $330 for the two. One was then loaded in my car for the trip home. The other is still in Seattle at a friends house until my next trip down in a few weeks.
Both are in very good condition. I was told however that when they plugged them in for testing it at least homes the transport but this one at least did no such thing. One of the fuses are blown. "Tested" my ass.
It says all over thing that it has "Digital Audio" but the back of the unit only has the usual composite out plus left and right RCA audio. No actual digital audio output. There is also a 25 pin D-sub connector so the changer can plug into the CO-V300 which apparently controls everything and does extras stuff like text superimposition and librarian functions. Neither machine came with one and the recycler said he did not see any come in either which means aside from some very limited functionality available form buttons inside the front of the changer there isn't a lot else it can do. :/
Thankfully however Pioneer silkscreened the pin designations for the port on both the rear interface bracket and the PCB the wire harness plugs into. Here is that pinout:

DB25----Name---Wire Color---PCB Connector---Name

1-------GND------BRN------------1----------GND
2-------DTA0-----RED------------2----------DATA0
3-------DTA1-----ONG------------3----------DATA1
4-------DTA2-----YLW------------4----------DATA2
5-------DTA3-----GRN------------5----------DATA3
6-------REQ------BLU------------6----------REQ
7-------RSTB-----PRP------------7----------RS
8-------TSTB-----GRY------------8----------TS
9-------RDWR-----WHT------------9----------RW
10------EXIST----BLK------------10---------EX
11------SELECT---BRN------------11---------AV
12------RELAY----RED------------12---------+12V
13------N/C
14-25---GND

There are other jumpers with silkscreened names but even without the controller there's not much more I can do without the service manual. I can find it floating around however. (Document number: ARP1850) This website even lets me preview a few pages before I pay for it but alas it is not already on ManualsLib.com. For the CO-V300 I can't even find a picture of it let alone a hoard of websites trying to sell me the service manual. (Document number: ARP1851)
I'd love the idea of consolidating my entire laserdisc library into two autochangers as there does not seem to be anything preventing you from using it for anything other than karaoke but I'm simply over my head on this one. Is there anyone in the laserdisc community who can shine a better light on the units or at least an idea of the signalling protocol it expects so a microcontroller replacement could be made up?