HIYA
HAVE HIT ON A STRANGE PROBLEM WITH A 4615.
WHEN YOU POWER UP, THE MACHINE STARTS TO RUN - THEN THE DISPLAY GOES OUT - MACHINE DEAD.
WHAT I HAVE FOUND IS THAT THE 5 VOLTS CUTS OUT, SECONDS AFTER POWERING UP.
tHE LONGER YOU LEAVE THE POWER OFF, THE LONGER THE 5VOLTS HANGS ROUND [UP TO 3 SECONDS MAX]
PRINTER VOLTAGE STAYS UP AT A HEALTHY 18VOLTS - INTERESTINGLY, THIS GOES TO MINUS 3.9VOLTS AT POWER OFF
SO THE BATTERY VOLTAGE IS OBVIOUSLY SITTING ON IT - IS THIS NORMAL?
NEVER HAD REASON TO CHECK IT BEFORE

IDEALLY, I WOULD LOVE TO GET HOLD OF A CIRCUIT DIAGRAM/SERVICE MANUAL BUT ANY HELP WOULD BE APPRECIATED
MANY THANKS
ANDY

Sounds like you have a dodgy transformer or a cap is short circuiting somewhere

the voltage from the transformer
is converted to printer voltage first, then 5 volts from that.
the printer voltage is constant - its the 5 v generater thats up the creek but it could be so many things, its almost impossible without a diagram.

Check R14 (0.33 ohm) sense resistor, U20 Oscillator IC, L1 Inductor, C11 (100uF 16v output cap), C10 and C15 (100uf 100v) sense caps

many thanks , will do on monday, thanks for the reply