No sound through speakers or headphones , cd spins, cassette tape turns.

The difference between cassette types is the length of the tape and the quality of the tape. Your recorder will work on all types of cassettes.

Is there any sound via the headphones? If it is normal but not on the speakers you have a faulty headphone socket.
If you turn it up to full volume can you hear anything? If you can then the main amp has failed.

Could be a bad wire from cassette player to speakers. Do you need to change setting from stereo to cassette

their is a good chance the amp or volume control has failed, the only other possible cause is that the headphone socket has got something inserted to cut the sound or has failed

try plugging headphones in if still no sound, its a fail end of life for item

hope it helps a little

I use a tape head adaptor . Tape cassette fits in as normal , the attached wire plugs into the headphone socket in either your personal cd player or mp3 player .

check your cables to the units channel that doesn't work, for breaks. Does the cassette player play back a pre-recorded tape okay? if it doesn't there might be a internal fault.
Check the wires to the tape head to see if one is off.

Could the tape be a Mono recording? Have you tried to clean the head on the tape player? This could fix it if the head is dirty. Do you use the tape player very often? It could have a dust build-up. Hope this helps...

Unit may have defective amp or blown speakers. Have serviced

Make sure speakers are still good and not blown

Here is the entire troubleshooting section from the manual.

Your problem is presumed to be a shorted speaker wire. I assume you're not getting the failure ONLY at extremely high volume levels.

Care and maintenance
Occasional care and maintenance of the unit and the software
are needed to optimize the performance of your unit.
To clean the cabinet
Use a soft and dry cloth. If the unit surfaces are extremely
dirty, use a soft cloth lightly moistened with mild detergent
solution. Do not use strong solvents such as alcohol, benzine
or thinner.
To clean the tape heads
Dirty tape heads cause sound deterioration. After every 10
hours of use, clean the tape heads with a head cleaning
cassette. Refer to the instructions of the cleaning cassette.
To demagnetize the tape heads
Use a demagnetizing cassette after every 20 to 30 hours of
use. Refer to the instructions of the demagnetizing cassette.
Care of CDs
When a CD becomes dirty, wipe it from the center out with a
cleaning cloth. After playing a CD, store it in its case. Do
not keep it in hot or humid places.
Care of tapes
Store tapes in their cases after use. Do not leave tapes near
magnets, motors, television sets, or any source of
magnetism. Do not expose tapes to direct sunlight, or leave
them in a car parked in direct sunlight.

REFERENCE
Troubleshooting
If your unit fails to perform properly, check the following guide
and the relevant sections of the Operating Instructions.
There is no sound.
•Are the speakers and AC power cord connected properly?
The unit shut off suddenly.
•Possibly a short circuit in the speaker terminals.
Disconnect the AC power cord from the AC power outlet
and re-connect the speaker cords correctly.
The unit blacks out when the unit is turned off.
•Is ECO mode set to on?
Erroneous display.
•Reset the unit.
Poor radio reception.
•Check antenna connection. Adjust the antenna to find the
best reception.
•Move unit and antenna away from other electric appliances
and cords.
The tape does not run.
•Is the deck in pause?
Poor tape sound.
•Check for dirty heads. Clean them if needed.
•Use type I (normal) tapes.
Cannot record.
•Is the erasure prevention tab of the tape broken off? If so,
cover the detection slot with adhesive tape.
The CD player works poorly.
•Is the disc correctly loaded?
•Is the disc dirty?
•Is the lens affected by condensation? If so, wait
approximately one hour and try again.
Resetting the unit
If an unusual condition occurs in the display window or the
cassette deck, reset the unit as follows:
1 Press POWER to turn off the power.
If the power cannot be turned off, disconnect the AC power
cord, then plug it in again.
2 Hold down s and press POWER.
Everything stored in memory after purchase is cleared.