# New Noise from MA RS-w12



## caper26

Hi all. I unplugged my Monitor Audio RS-w12 subwoofer to test another. When I plugged it back in, it is making an electrical noise from the woofer, no matter what the gain knob is set to (the volume doesn't change). It was NOT there earlier, and it is not the cable tv signal (I unplugged that). I makes the noise when stand-alone (no cables besides power). It only happens when the power is "ON" (light is green), not in standby when the light is red. When I move the RCA jacks in the back, the noise lessens. I noticed this while plugging/unplugging cables, so I assume something happened to the Amp when I unplugged the cables to test my other sub. Suggestions? I am awesome with a soldering iron (ie, I have mod-chipped about 50 PS2's in the past with 30 awg wire).


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## lcaillo

Look for a broken connection on your grounds at the input connectors.


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## caper26

lcaillo said:


> Look for a broken connection on your grounds at the input connectors.


So you mean the RCA jack inputs? Problem is, I can only see the backside of the circuit-board, not the side with the connectors. Suggestions?


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## lcaillo

You will need to take the unit apart, which may be a challenge. Many are difficult to get to.


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## caper26

lcaillo said:


> You will need to take the unit apart, which may be a challenge. Many are difficult to get to.


I will see what I can do. Nothing to lose really since I am prepared to get a replacement amp. I read on a bunch of Avforums and noticed I am not the only one to run into this problem so I think it is a defect of some sort. Same goes for my "on/auto on/off". If I lose power with the main power switch on, the sub will NOT come back no matter what, until I power it down for a long period of time (such as in the case of a storm outside and we lose power, or if I knock the power cable off the amp by accident). I think the amp just has a few flaws and they fixed them in the newer RX models (vice RS). Some people think it is the transformer making that noise. There is a huge transformer bolted to the bottom of the inside of the cabinet.


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## caper26

I took it all apart, reflowed a bunch of solder connections, and basically "bent" all surface mount resistors and caps since it seems like something was loose. It made the noise again (buzz/hum) from the woofer, but it went away after about 1 minute. I tested it again in the living room and it did the same thing...seems to go away once it is 'on' for a bit. I can live with that.


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## ankuse

Same exact problem just started on my MA RSw12, I called MA and they said to try the new amp, going to install it today, but it was pretty pricey for the amp assembly. Any suggestions on taking the sub apart? Do you have any photos of when you did it.


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## caper26

The sub is easy to take apart. Driver is first with Allen Key bit. A bunch of wood screws on the back. The only thing that I remember being weird was the bolt holding the transformer in place. I think it was too long for a socket or something. I don't remember exactly but I remember something about not having the right tool, and I have quite a bit of tools. Yeah, maybe it is the transformer bolt head on the bottom of the sub, I think it maybe a huge allan key or something. Anyway, I was able to improvise and finish the job easily. I think the new amp is on the sub in the picture. Working great for almost 6 months now...


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## ankuse

Thanks. I just took it apart, what a pain, the transformer bolt had this black glue like substance, making it impossible to remove without scrapping it off which took quite some time and yes, the transformer nut is an odd size so socket sets won't really work unless it is the right deep socket. However when I went to reinstall the new amp plate does not fit into the opening. The circuit board on the left side touches the opening and thus the plate does not line up to the screws and the indent opening. I am going to have to sand down 1 or 2 millimeters on the left side to get it to line up and fit. Did you also have that issue?


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## caper26

No. Mine dropped right into place like a lego block. Sorry about your woes. It will be fine in the end.


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