Ok, but thats speaker level, not line level..I realize that could be stepped down, but I wondered if there was an RCA or line level available on the PCBs.
You could easily use what's called a "direct box" to interface the speaker level from the speaker terminals on the jukebox to drop the level to line level or mic level to feed another amplifier.
They have some Rockola juke guys there who could answer your questions. It's possible that Rockola may have made an amplifier accessory kit for patching the jukebox to other amplifiers.