Wurlitzer 112, harsh buzz in some of the lower notes

[CharleyC]

Hello All,

I have been working on a Wurlitzer 112 and have come across an issue. A few of the notes in the lower quarter have a harsh buzz and I think it is a problem with the reed bar but I am not sure, could use an expert's guidance. I just recently replaced the cracked original power cord with a new grounded three prong one, and I could have a problem with a cold solder joint or something inside the amp, but I don't think so because when the amp is disconnected from the reed bar there is just a little bit of noise. Even when the reed bar is connected there is just noise that is caused by the amp but when I play some notes it goes nuts with crazy buzz. keys 30-64 all sound great. I attached the ground of the new power cord to a screw on the inside of the chassis that is connected to the transformer. I am going to try and clean the reed bar with compressed air when I get a chance and see if it is just shorted by dust (I hope that is all it is). But could it be a problem inside the amp/ with the new power cord if only a some of the notes create the buzz?

Thanks in advance for your help

[OZDOC]

Hi Charley
This sort of instrument is very prone to noises caused by dust contamination between the reed and the common plate.
I think your plan of doing a thorough clean is the right place to start.
Sometimes sliding a small piece of bond paper into the reed gap can be used to clean grit from a gap.

[pianotuner steveo]

I agree. Just remember, when you clean with compressed air, whether a real compressor or in cans, it temporarily adds moisture, (unless there is a water trap on the real compressor) so the noise may be worse until it evaporates.i always wear a mask when doing this. Who knows if mice have been inside, and also the cans of air have an odor, not sure what the gas is but I'm sure it's not healthy to breathe in.

[CharleyC]

So I cleaned it and the problem persisted, some notes just were really harsh with their buzzing. I need to try and clean it again, but I am starting to think it might be a humidity problem - the buzzing started happening when the weather started to get hot and humid. Is there a work around to the humidity in the air/ moisture on the reed bar other than finding a dryer room? Or is cleaning it more thoroughly the best move in this situation?
Thanks again,

Charley

[pianotuner steveo]

I would try to clean it more- a bright flashlight held under the reeds may help to see if something is shorting out a reed. Also- if you see any sparks on the noisy reeds, that means the reeds are crooked and shorting out on the side the sparks are on. Never file the sides of a reed or the pickup to increase the gap. This will drastically lower the volume and you can't reverse it if it is done.

[rcewilson]

I have been servicing the two 140B's at Fame Recording in Muscle Shoals for about 10 years.  As far as I know these are the same two pianos that have been there since the 60's.  One of them seems to have a lot better tone than the other and is the one used now most of the time.  I have only replaced a few reeds and some electronic parts in the amp.  When they record they normally just mike the speaker. 
Bob

[pianotuner steveo]

I think this last post was posted in the wrong spot...