Help me to test Marantz SD-74 cassette player

[sairfan1]

I have an old cassette player from 80s which is not working, its power ONs but no further response, after some inspection I belive there could be issue with LC6502B OR LM6402H I tried to find datasheet on the internet but could not find enough so that I can test it. (BTW I'm not experienced in reparing)

Some pins of LC6502B are directly connected to VFD display (Fluorescent display) and some go to VFD Driver AN6870N
VFD segment who are directly connected to LC6502B are OFF (not litting) same is the case with LM6402H some of its pins are connected to front pannel (via TC7800) for play/stop/forward etc. buttons, but no response on pressing buttons, related LEDs stay OFF

I tried to find datasheet for LC6502B/LM6402H could not find something informative but looks thease are 4 bit microcontrollers, I was not able to find any information that can help to understand expected voltage/signal on its different pins,

I'm looking for help, based on this information can I investigate LC6502B/LM6402H are the reall problem?

EDITED: describe further and include pictures

[wasedadoc]

Photo?

[z2000]

I have the Marantz SD 74 service manual. I don’t know how to load it here or send it to you if you need it.

[wasedadoc]

Complete mix of Japanese ICs.  I suspect the LC6502 one is a Sharp device.

Does the motor run when it should?