Rockola 48350-1A amp hum

[Rob Blakeslee]

I have a Rockola 460 jukebox with a 48350-1a amp. Since I bought this
jukebox a few weeks ago, it has always had a hum and here are the
symptoms:

1) Hum is present the second the jukebox is turned on
2) The hum does not get louder when the volume is turned up
3) The hum does not go away when the volume connector is unplugged or
when the input from the cartridge is unplugged
4) The hum is gone when I disconnect the amp or when I disconnect the
speakers.

I did replace C35 and C36 on the amp supply board (49150-2A) today
hoping that would fix the problem. No luck. It was brought to my
attention that the jumper wire under C37 was cut. Does anyone know if
this is normal? This jumper connects C33, R37, R38 and SCR1 together.

Thanks for any and all advice !!

Rob