Rockola 488

Hi
Looking for a bit of help for a Rockola 488 jukebox. Firstly all connections are connected up and all fuses are fine and have the manual.
The machine selects ok for selections ending in 0,1,2,3,4.
For selections ending in 5 the its a bit hit and miss sometimes the selection will be ok other times it will select the next record on(for example- if i select 155 it will select 165)., note the digital display is displaying 155
If i make any higher selections for those ending in 6 and 7, it will not select the right record and will be 1 or 2 record spaces further on(for example if i select 157, it will stop and select 177), note the digital display is displaying 157.
Has anyone any suggestions or ideas, it may possibly be a logic board problem
It seems if the machine counting process is out of syn
regards
Clones

Any takers

Clones,
Since there are"no takers"--I'll take a guess--
Dirty opto sensor wheel ??
Ron Rich

Hi Ron
Gave the opto assembly and encoder a clean, after about an hour of adjusting the opto up and down, i got it working. Those optos are a real pain, a very tiny adjustment in movement seems to make a difference and the connecter to the pcb is not great. I'm not a big fan of these rockolas with the logic boards and profit setters, they won't be around as long as earlier machines and seem to give more trouble than the machines from the sixties and early seventies
regards
clones

Hi Clones,
Glad you "got it" ! Yes--in theory, "opto's" are foolproof--but in the "real world", they can not be considered thus.
When we were designing the Seeburg replacement MCU, we thought about an opto for the (mechanical) detent switch, as there are many "problems" with that switch (MOSTLY "people caused"). The cost would have added too much, to an already costly unit, so we came up with several "work-arounds" inside the new MCU. Ron Rich