Problems with Celestron 11" Ultima clock drive

I am posting this for my next door neighbor (who doesn't do Usenet).

The clock drive on his 1991 Celestron Ultima (11", fork mount)
telescope stopped working. When he tries to turn the drive on all
that happens is that one of the lights starts flashing. The manual
says that this indicates that battery needs to be replaced. He tried
this several times without success. There does not appear to be
anything physically wrong with the drive and it works fine manually.

He then contacted Celestron tech support and was told that they
neither repaired nor had parts for this model/year of drive. Their
suggestion was to buy a new GEM with a dovetail mount. This is a
rather expensive solution to what is probably a minor failure.

Does anyone know of any place that can repair this drive? Is there a
source for the schematic of the electronics in this drive? Any other
suggestions?

Thank you,
Charlie