Lasonic 931 tape deck "b" no sound

Hi everyone, as for title tape deck "b" is giving no sound despite spinning normally, ff and rev are working fine too (belts replaced).
No sound from earphones either and no VU Leds reaction.
Everything else is working great.
I've tried EVERYTHING aside from replacing IC LA3220 (I challenge you guys suggesting something i didn't try already, schematics purchased but no luck for now.
Anyone had a similar problem? Any ideas?
Thanks!!

Check tape head wires both at head and on board. Also tape head itself could be bad. Does tape A work? The function switch could also have issues.

Thanks for your answer.
I checked the wires for continuity between the head and the board and i checked the solder joints. All was ok.
Towards the end of the troubleshooting process i even replaced the head with another one from a functional cassette deck. Still no sound.
Tape "a" is working fine, and everything else is working great.
I wouldn't mind keeping it this way, but i usually don't give up on repairs... however, this time i really don't know what to do anymore.

Did you check to see that tape head fully engages over tape?

I thought myself that seems to be the most likely cause, also because if i touch the head with a screwdriver while it's playing, i get the static "bump" from the speakers.
I've tried to make sure it does contact well: i also used a see-through cassette to make sure the head was pressing properly the tape towards the pad, and it seems to me it does, but i'm not a tape deck expert, so i may be wrong.
Is there a way to find out if it for sure does?

Forward a little and play again. may be that part of the tape had no sound. Reverse the tape and try playing again. Increase the volume to 1/3 and see it volume was not set right.

Try another tape that you know for sure it plays well.

BoomboxLover48 said:

Forward a little and play again. may be that part of the tape had no sound. Reverse the tape and try playing again. Increase the volume to 1/3 and see it volume was not set right.

Try another tape that you know for sure it plays well.

Click to expand...

Tape "a" is working...