Emax

Hi all,

I managed to get an Emax, but unfortunately there is a fault. Most of the front panel buttons are not working, and the ones that do are not doing the correct function. From the numbers and arrows, only 7, 9, and 0 seem to work, and 7 and 9 seem to do the sideways arrows function sometimes. 

Machine can load discs, and can playback sequences, but the only 'Modules' switch that is working is 'preset management', and that brings up the 'master' menu!

LCD and sliders work OK.

I have checked panel board and looks ok, also all switches work ok and have tested lead to mainboard and all connections are ok.

Have read this could be the 'scanner MPU', but cannot see a chip called "6500/11" nor "IM-386 R1125" nor "6502 Rockwell". Does anyone know where this chip is located? In any case, I have heard this can't be replaced these days, but I'm thinking maybe it is another chip that has gone such as a CD74HCT273E CMOS Logic Octal D-Type Flip-Flop (not sure what these do, but they seem to look directly at the ribbon cable coming from the display).

Any help would be much appreciated. I am ok with a soldering iron and have multimeter + oscilloscope so can run any checks anyone thinks are appropriate. Failing that, if there is anyone in the UK that fixes these old birds, please let me know!

Thanks,

Nik