Proceed CD Library

@tonyaudio
Can you provide some picture of the battery compartment?
What you need is a 4.8V battery pack connect or clip to the battery compartment + and - terminal to make it work or see if the Communicator (the controller) still in working condition.
If you got 4 of those 1/2C rechargeable NiCad battery on hand, add some conductive spacer to make it to correct length.

That sounds like it would work but what kind of a conductive spacer can I make or buy that you think would work best? I probably need about 3/4" in length to fill the gap, width is perfect. I am connecting them in series not in parallel so as you say that would give me 4.8 Volts.

My suggestion is cut a piece of 1" dia wood to 1/2"-5/8" length, drill and insert a 3/16" dia x 3/4" copper rod in the center.

Another option just for testing purposes would be a DC voltage power supply that is adjustable.
We use them at work, that way you could set to 4.85vdc and clip to the posts and see if it at least works.

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F113712045556

Just an example, tons of options on ebay