JVC RC-656 tape sound muffles

[bobmonkhouse]

I've got a beaten up 656, somebody cleaned it up inside for me and changed the belts.
The radio and line-in work well but the sound when playing tapes is not good; it sounds muffled.
Does anybody have an idea if it's fixable, if it's the head to blame or could be something else?

 

[docs]

Could be azimuth which is adjustable via small screw on the head. Have a research into that.

 

[bobmonkhouse]

I will. Thanks a lot!