Found the problem
In case anyone has the same problem I'll post the fix.
"Playback on channel 1&2 NOT PLAYING BACK THRU MIXER SECTION.
Solution got from the Tascam board
"The two insert channels on the bottom front of the 488(that have been in use for awhile)need to be cleaned and lube.
An insert jack has a contact which closes when a plug is NOT inserted into the jack. The contact connects the preamp output to the rest of the channel strip. When the insert plug is in the jack, this contact disconnects. Then the tip of the plug carries the preamp output to the insertion effect, and the ring brings the modified signal back to the channel strip.
The trouble is that the contact is dirty, and is not making good contact. This usually happens when the insert is left unused for a long time.
This is what I bought:NOTE: (Name change in 2006: From CaiLube MCL to DeoxIT FaderLube, part numbers remain the same)
• CaiLube MCL will change to DeoxIT® FaderLube
