Hi,
I got this unit, Garrard MRM-101, in its original condition. The unit buzzes very loudly, sounds like a 50Hz square wave tone which is my mains frequency.
The buzz happens about 1-2 seconds after turning on.
The buzz goes away when I turn on the suppressor but there's no sound coming from the turntable.
The grounding point for the phono seem a bit suspect so I replaced the push button with a speaker binding post to no avail.
My first thought is the mains filter capacitors are out so I will be ordering new ones - along with the other capacitors on the boards.
Has anybody came across this problem on the Garrard Music Recovery Module?
Garrard MRM 101 Music Recovery Module Manual | Vinyl Engine
I got this unit, Garrard MRM-101, in its original condition. The unit buzzes very loudly, sounds like a 50Hz square wave tone which is my mains frequency.
The buzz happens about 1-2 seconds after turning on.
The buzz goes away when I turn on the suppressor but there's no sound coming from the turntable.
The grounding point for the phono seem a bit suspect so I replaced the push button with a speaker binding post to no avail.
My first thought is the mains filter capacitors are out so I will be ordering new ones - along with the other capacitors on the boards.
Has anybody came across this problem on the Garrard Music Recovery Module?
Garrard MRM 101 Music Recovery Module Manual | Vinyl Engine
Ah it seems I posted this too soon.
I disconnected the phono from my stereo setup but then I thought about testing the input/output jacks. I used my cheaper headphone setup instead so I won't blow up the whole room with my speakers if something goes wrong.
With the phono to headphone amp, no turntable, there's a mid level hum at mains frequency.
Connected to turntable, the loud buzzing came again, but only on the left channel. I played with the headphone amp volume and the noise follows suit.
I touched the left phono in jack and the loud buzz increased. I continued to wiggle and play with the connector and the noise crackled until no loud buzzing anymore. Only the mid level hum.
The input/output contacts are oxidized so I think replacing them with fresh sockets will help.
I tried playing a record and it works. But still the hum persists, which I think has to do with the grounding somewhere. This happens with two different headphone amplifiers. They are both silent otherwise from other sources.
With regards to the suppressor - it doesn't work and I can only hear the turntable very faintly. The rotary switch does need some cleaning I suppose because playing with it causes some crackling - though I don't see the point since I don't see myself using the noise suppression feature.
But fixing this would be a nice thing to do.
First order of business I guess would be to replace the RCA sockets as well as the tired electrolytics.
What could be the cause of the hum?
I disconnected the phono from my stereo setup but then I thought about testing the input/output jacks. I used my cheaper headphone setup instead so I won't blow up the whole room with my speakers if something goes wrong.
With the phono to headphone amp, no turntable, there's a mid level hum at mains frequency.
Connected to turntable, the loud buzzing came again, but only on the left channel. I played with the headphone amp volume and the noise follows suit.
I touched the left phono in jack and the loud buzz increased. I continued to wiggle and play with the connector and the noise crackled until no loud buzzing anymore. Only the mid level hum.
The input/output contacts are oxidized so I think replacing them with fresh sockets will help.
I tried playing a record and it works. But still the hum persists, which I think has to do with the grounding somewhere. This happens with two different headphone amplifiers. They are both silent otherwise from other sources.
With regards to the suppressor - it doesn't work and I can only hear the turntable very faintly. The rotary switch does need some cleaning I suppose because playing with it causes some crackling - though I don't see the point since I don't see myself using the noise suppression feature.
But fixing this would be a nice thing to do.
First order of business I guess would be to replace the RCA sockets as well as the tired electrolytics.
What could be the cause of the hum?