Vintage Synth Repair

howdy folks:
longtime Juno 106 user (first keyboard i ever bought in 1984 - still use the same one). i use 
the keyboard on stage a lot and i've been experiencing something new that i can't say is 
enjoyable:
basically, in the middle of playing, the synth will turn itself off, most  of the lights 
("save/load/write" included) will blink on unison for about 3 seconds, and then the keyboard 
will usually remain off until i turn the power switch off and on again... sometimes this won't 
turn the keyboard back on again and waiting time is required - not the greatest thing in the 
middle of a song on stage!
has anyone else experience this before? anybody heard of this? any suggestions on how to fix 
it?
any help would be greatly appreciated,
thank you
-Jamie