Rowe MM5 Low Frequency issue

My MM5 has terrible audio, just seems distorted and no low end.
I have recapped the Power amp and all the electrolytic s in the pre-amp assembly as well as the 22uF and 68uF in the speaker networks.
Bench tested the amp and it has a fairly good audio response but the pre-amp doesn't seem to have a very good low freq function.
If I disconnect one channel feeding the pre-amp I get better low freq.
This thing sounds like crap, speakers do not appear to be dragging or having any issues.
Has anyone dealt with this kind of issue before?
Thanks.

Is this machine equipped with a tube power amplifier and transistor preamplifier?

If so, double check the resistors in the output stage of the tube amplifier around the 7868 tubes. I've seen several of those become way off value because of the heat build up over the years.

Have you checked to be sure that the pickup is wired out of phase.

The older Rowe machines placed the bass speaker(s) across both channels so as make them mono. This necessitates a few changes from normal circuit design and wiring.

Also, be sure to carefully clean and slightly tighten the edge connector on the preamp card. I've had frequent problems with these and just finished modifying one of the outboard preamp boxes for a different application. I removed the edge connector and soldered the leads directly onto the board.

Rob/NYC