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.[/quote]

Is anyone capable of of answering the question of if the "RED" electronics could be used in place of the "YELLOW"? I found a "RED" preamp/power amplifier unit for sale.