if you are getting a cherry pay, then a bunch of stuff is working.
there's 3 places that typically cause issues when certain pays don't work:
1] the reel wiper boards (things with the brass rivets) are cruddy.
2] the copper traces on the payout counter disc are cruddy
3] the plug pins on the hopper and/or reel mech are cruddy
you can use something like a maroon 3M pad, a green scrub pad, synthetic steel wool, etc. to clean the black stuff on the rivets/traces/pins. Isopropyl alcohol will help too.
if that doesn't fix it, yell and let us know if you have a jumper wire handy ... the kind with alligator clips on both ends.
if you can't post pictures here due to size limitations, you can email some to slotpics@cdyn.com and I'll downsize and post them for you. If possible, please email the highest possible resolution pictures of the entire game front and as many pics of the internals as you have the patience for to that email. The entire sides of various units and inside the cabinet are ideal.
you can find the schematic and other docs for an 804H at
https://bingo.cdyn.com/slots/there's some pics also, but not enough. Ideally a pic of at least the payout counter on the hopper and the left/right/back side of the reel mech would be great.