Rock-Ola Model C-X "Rock" Wall Mount Problem

I just brought home a wall mount Rock-Ola Model C-X "Rock" CD jukebox
with SyberSonic electronics. The keyboard is dead and the mech will
not scan. When I press the DIAG button it says it will give an error
code in the computer digital display after 30 seconds if the keyboard
is inoperative, but nothing in the display.
Any suggestions on what to check first? Does a fuse control both of
these functions? The phone wire from the keyboard to the computer is
securely in place. Just looking for advice on what to check first.
Thanks.

Follow up...I checked the 4 fuses in the power supply and they were
all good. The Power supply LED's are all lit. Everything looks good
inside and I rechecked all of the cables. I get the illumination but
nothing in the keyboard or mech.
Suggestions anyone? Thanks.

Mark,

If memory serves me correctly, the keyboard has an on-board +5 regulator. The telecom cable merely delivers a setup voltage, ground and data xmission lines.

However, if all is right with the rest of the box, the mech should scan to home upon power up. You might also want to check the regulator on the Control Computer. I have seen a number of these fail in the past.

David