Phonoland

Howdy,
Tonight I was p,aging my rockola 484 and all of a sudden a loud air raid siren noise at full volume came out of the speakers. I replicated it after turning it off and then on again, it p,Ayer for a few moments and en sound and the speaker overload light went on and the noise. I do have a motorized remote volume kit installed.

I removed the volume controll from the unit, and I reseated the speakers plug on the amp and front door. It's played for a bit fine but I have no friggin clue what's going on.
Ed

Ok more info here,
It did it with the original volume plugged in, so not either of the volume controls.
I was able to unplug the pickup and it changed slightly but it's still there and louse as heck.

And my dogs are traumatized now.
Ed

Cold solder joints on the pc boards in the amplifier? Bad electrolytics in amplifier?

Overloaded speakers connected to amplifier?

Pull the pickup connector--stops, the problem is in that connector to the pick-up--still does it, problem is internal to the amp--
Ron Rich

I haven't been able to try anything. The noise made my dog jump into the table. Fracturing her skull, and I ended up in the e-vet.
Ed

I was able to do some troubleshooting.
It made the noise with the pickup unplugged, so it's I the amp.
I did find some cold solder joints on the driver boards. I'm hoping this was it.
Before I called it good I readjusted the 9.6 Vedic on the power supply.
I also did the sound system adjustments as per page 63 of the manual. But I'm confused about the second adjustment of r33. Is it supposed to be .033 or do they really mean .0033 . The reason I asked this is the left driver board starts out at .007 the right one starts at .001 but my dim doesn't display vex that precise down to 4.

Thanks
Ed

What the solution was!!

The amp compactors in the small power supply board we really bad. I had to take it to a local repair shop to find this out. Luckily he showed me how he diagnosed it. Not I own a esr meter.
Ed

Ed, having the same loud issue randomly. Are you saying that your trouble was the power supply "capacitors" for the amp. You mentioned "small board"--is that in the power unit?

Hi
Have had that problem in particular on the later rockolas, i think the term is motorboating for the sound you hear, on previous amps i have had the problem was the power transistor on the amp driver boards, although i would say a multitude of other things could cause it
Clones