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Topic: Mosvalve 500: Dirty Pots |
Bob Snelgrove
From:
san jose, ca
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Posted 31 Dec 2010 3:55 pm |
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Guys,
My gain controls are beyond scratchy. Lately, I lose all signal unless I turn, wiggle, etc. I just got the Caig contact spray so before I pull it out of the rack I thought I'd check on how to get to the pots?
thx
bob |
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Tim Marcus
From:
San Francisco, CA
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Posted 31 Dec 2010 4:06 pm
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take the top off and you should see them in there. Sometimes it takes some fiddling with the red tube to get it into the right place to spray out the pots.
when you say "wiggle" my suspicion is that those pots may be soldered directly onto a circuit board. If they are - take a close look at the solder connections to the circuit board. If you see hairline fractures or worse you will want to re-solder them. Usually a fresh flow of solder lasts another 10 years or so. Heat and vibration will eventually destroy the solder points.
_________________
Milkmansound.com |
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Bob Snelgrove
From:
san jose, ca
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Posted 31 Dec 2010 4:57 pm
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I think someone said that they were 'encoders" not pots? They click as you turn them.
bob |
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Brad Sarno
From:
St. Louis, MO USA
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Posted 31 Dec 2010 5:30 pm
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No, they're still just pots, just with a spring loaded click feel going on. You should be able to spray them when inside the amp. I bet they come back to life.
And yeah, you may need to hit the points with solder.
B |
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Jack Stoner
From:
Kansas City, MO
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Posted 1 Jan 2011 3:51 am
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| I had a MV500 power amp. The pots in it were noisy and spraying didn't help - they would only last a short time and start making noise again. I called Genz Benz and got four new exact replacements. |
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Erv Niehaus
From:
Litchfield, MN, USA
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Posted 1 Jan 2011 8:48 am
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| I have replaced pots on Tube Works (Genz Benz) euipment in the past. The Company gives excellent service and the pots are very resonable. You need to solder them to the board but not really a big deal. |
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Jerry Overstreet
From:
Louisville Ky
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Posted 1 Jan 2011 9:17 am
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What Jack and Erv said. Same here. TubeWorks gear is notorious for deteriorating pots. Happened with 2 out of my 3 pieces.
Cleaning them does no good. Best to replace them and forget it.
I really like the sound and everything else otherwise, so to me, it's worth the hassle of replacing the pots.
The 500 is the only piece I've not had pot trouble with, so I can't advise on the procedure. I'm not sure how much disassembly is required to get at them. |
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Olli Haavisto
From:
Jarvenpaa,Finland
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Posted 1 Jan 2011 9:36 am
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Just turn them flat-out and leave them.
Adjust the volume elsewhere.
_________________
Olli Haavisto
Finland |
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Bob Snelgrove
From:
san jose, ca
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Posted 1 Jan 2011 11:09 am
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| Olli Haavisto wrote: |
Just turn them flat-out and leave them.
Adjust the volume elsewhere. |
I run them at 50% and do leave them. We did a gig and when I brought it back and set it up, 1 channel had no sound so I had to start twiddling 
Anyone have the part number of the pots or a link?
thx
bob |
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Jerry Overstreet
From:
Louisville Ky
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Posted 1 Jan 2011 11:46 am
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| Bob Snelgrove wrote: |
| Olli Haavisto wrote: |
Just turn them flat-out and leave them.
Adjust the volume elsewhere. |
I run them at 50% and do leave them. We did a gig and when I brought it back and set it up, 1 channel had no sound so I had to start twiddling
Anyone have the part number of the pots or a link?
thx
bob |
Yes, therein lies the problem. The pot circuits will cut out and leave you with no sound sporadically, intermittently and with no warning at the worst possible times. Sometimes, just moving or bumping the equipment will result in this condition. This happened to me on more than one occasion. Pretty annoying not to mention embarrassing. Only sure fix is to replace 'em. I love the old BK Butler designed gear, but the pots are pure crap.
You can get information at: www.genzbenz.com Perhaps they can supply replacement pots.
I suppose if someone knew the design and value of the originals, you might be able to get better parts at more reasonable cost as GB prices are ridiculous in my experience.
Sorry, can't help you there. |
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Dave Ristrim
From:
Whites Creek, TN
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Posted 5 Jan 2011 3:33 am
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| Bob, if you order the parts, please send me the part numbers as I need to replace some myself. They've been giving me trouble for decades. The Genz people are very nice as I've talked to them in the past. |
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Jack Stoner
From:
Kansas City, MO
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Posted 5 Jan 2011 5:04 am
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| If you call Genz Benz, they don't need part numbers, they know what is needed. |
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Dave Ristrim
From:
Whites Creek, TN
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Posted 5 Jan 2011 6:09 am
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| Many thanks. |
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Erv Niehaus
From:
Litchfield, MN, USA
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Posted 5 Jan 2011 7:57 am
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| They've got a section on their web site just for discontinued Tube Works stuff. |
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Gary Walker
From:
Morro Bay, CA
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Posted 16 Jan 2011 10:11 pm
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| Dirty Pots? Tidy Bowl works best around our house. (Sorry about that Chief) |
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Steve Schmidt
From:
Ramsey, MN, USA
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Posted 17 Jan 2011 8:58 am
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I just replaced all 4 pots in my Mosvalve 500 about a month ago. Just pay attention and take your time. I was done in about a half hour. Some people like the solder wick. I prefer a solder sucker. Don't use too hot of an iron, and you should have no problems.
steve |
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