453 Amp Muting and overload issues

[chris1087]

Hi , on my 453 amp I have a couple of issues. I think I know the answer but would like to confirm.

1st I had a popping on the sound when the mute relay was released. I took the relay out and the popping stopped. I replaced with a new one and happened to notice that the same happened. But also that the amp was not really muted so that’s why it still pops. But why doesn’t it mute when the contacts physically switch ? Second is that the speaker obverload light is alway lit.

Assume you will say an amp rebuild is needed. Just do not understand the muting issue.

[jukenorman]

It's hard to understand why the mute relay contacts don't work because they ground the signal into the driver boards at the balance control - wiring fault? There is a note on the schematic to say that the overload light is dimly lit during normal operation.

Norman.

[chris1087]

Hi Norman,

Cant see that on my manual, thought I may have a smoking gun with the light on , obviously not. Starnge with the mute relay. looking at page 79 The play relay socket if fixed to the board. pins 1-4 are play and normally open. There must be something very wrong wiring wise. I will check it. TBH honest the sound is a little muddy & I suspect I am going to have to replace the caps. Cant think though of why it will not mute unless there is a short or wiring fault as you say. I will let you know how I go.

Edit: Am I correct in thinking that without the relay there should be no audio? There is

[jukenorman]

What amplifier do you have? I only have a pdf of the 453 manual which has no amp schematic. I have been referring to the amp schematic 453-54 which can be found here arcarc.xmission.com/PDF_Jukebox/Rockola/Schematics/

With the relay removed you will get sound; the energised relay grounds the signal so with the relay removed, it will not do that.


Norman.

[chris1087]

Its a 48350 -A. I do have the full schematic in my manual. I see refereed to that and can see what you mean. OK, time to take it apart then.