I opened the unit to replace the belts that had turned to goo. I got almost all of the goo cleaned up from the inside. Put batteries in and the radio works but is not very loud.  There was battery corrosion inside and looks like there may be damage to the PCB near the battery terminal.  The cassette motor does turn when play is engaged.  I did not have the proper size belts so I did not go any further, the repair this needs is beyond what I work on.  Also I noticed the yellow switch on the side does not seem to slide properly. 

If you have any other questions please send me a message.