Boss MZ-2 Digital metalizer broken need help troubleshooting

[PoPo75]

Hell all, I have an old (1990s) Boss MZ-2 Digital Metalizer that stopped working. The LED goes on and off when the pedal is pushed but absolutely no sound comes out. I'm using a battery not the AC adapter. Where can I start to troubleshoot this? Thanks for any help

[Jazz P Bass]

Can you locate a schematic.

If so, post it here.

[nosaj]

Can you locate a schematic.

If so, post it here.

Here.Boss_MZ-2_Metalizer_Service_Manual.pdf
nosaj

[PoPo75]

Wow. That's a nice schematic. Thank you!