Akai S1000 / S1100 samplers

hi all,

thank you for the add :)

i'm hoping there are some s1000 gurus in here that can help me debug my main board!

i recently picked up an s1000 that was dead on arrival. i have replaced the 5v psu with a modern equivalent and confirmed the expected voltages from both power supplies now. the +12v & -12v psu on the main board has been recapped but was functional beforehand.

since replacing the 5v psu, the backlight of the screen now turns on but the display is completely blank. the function button LEDs are not lighting up which i'm assuming indicates the sampler is not booting up at all.

most testing has been conducted with no scsi board or memory expansion boards installed. i have been told the sampler should be able up boot in this state because there is memory installed on the main board, would be good if someone else can confirm this?

additionally, to rule out shorts or issues elsewhere on the sampler i have disconnected everything else asides from the 5v psu input, the other psu input for the +12/-12 psu, power to the display inverter, the connection from the inverter the display, the display data cable & the function button cable.

i ordered a couple replacement 2mb memory expansions and eproms from japan, installed both and still not booting :( also triple checked all connector locations & orientations, cleaned header contacts with iso.

i haven't got the schematics for the s1000 and it would be amazing if someone could share them, but so far all i have been able to probe on the main board is that 5v is present at all the decoupling caps near the cpu's & various IC's.

any further advice on how to debug this issue would be greatly appreciated, such as specific locations to probe and check for the expected voltages!

thank you