So is the digital decoder board on the CD PRO 2 unit or in the Preamp/control/amplifier 70038-1A unit?[/quote]


After looking at the CD PRO unit and tracing the wiring it looks like the audio goes to a pair of RCA female jacks which have the interconnect cable that runs to the preamp/power amplifier module.

Therefore having replaced the CD PRO unit with a rebuilt unit the problem then lies in the preamp/power amplifier section.

Thanks for all the help people.