91 GT-S Stock CD player-no volume?!

[TBayToyotaBoy]

I've tried searching both the Camry and Celica forums because the same CD deck was installed in them in 91, no luck on this one...

The original CD/tape deck in my GTS still works, but the CD function has almost no volume. Tape and radio have normal volume control, but when I play a CD: I can turn the volume to maximum, and still barely hear what's playing. I'd prefer not to swap-in my good aftermarket deck until next spring, so can anyone help me on this one to limp the factory CD player through the winter?

Thanks for any ideas...hopefully I won't have to solder anything.