View Single Post
  #2  
Old August 11th 20, 05:50 AM posted to alt.collecting.juke-boxes
John Robertson
external usenet poster
 
Posts: 901
Default Rock ola 474 amp

On 2020/08/10 12:37 p.m., Dave N. wrote:
I just pick up two Rockola 474's and the one I'm working on has static
in the right speaker all the time sometimes you can hear it over the
music. I have replaced most all of the electrolytic capacitors on the
driver board, the pre amp and the power board with no change in the
noise. has any one ever had this before.

Thank you for your help

Dave Niccum
Georgetown, Il USA





Unlikely to be a capacitor, more likely a resistor or transistor or even
a noisy electrical connection.

First, try unplugging the input to the amp. If that solves the noise
then check the cartridge and wiring.

When you adjust the volume does the noise go up/down with it?

If yes, then the problem is either the volume control or in the pre-amp.

If it doesn't change then the problem is most likely in the power amp
section.

An audio signal tracer is what you want to track that down!

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
Ads