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Topic: MSA volume pot |
Alvin Douglas
From:
Prince Edward Island
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Posted 28 Jan 2014 5:17 am |
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The volume pot has been bypassed on my 1974 MSA Classic. I removed it and the ohmmeter tells me it's open. No numbers on it so I have no idea what value or model it is. I called MSA but could not seem to find anyone to talk to. Does anyone know the specs for an OEM volume pot for this guitar? Any info re where/how to source one would be appreciated.
Thanks in advance.
Alvin |
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Jerry Jones
From:
Franklin, Tenn.
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Posted 28 Jan 2014 6:40 am
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Turn the pot to about half-way and see if you get a reading between the wiper (center) tab and either of the outside tabs.
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Jerry Jones |
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Lane Gray
From:
Topeka, KS
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Posted 28 Jan 2014 7:27 am
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500K mini pot. The Jaw-dropping bit is that it is rated for 5A.
_________________
2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects |
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Alvin Douglas
From:
Prince Edward Island
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Posted 28 Jan 2014 7:51 am
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| I had another look at the resistance. There is no reading between the 2 fixed terminals. There is a small reading between the wiper and each fixed terminal when the wiper is hard over to that terminal. Its telling me that the middle section of the resistor is open. Thanks for the info re 500k pot rated at 5 amps. Hard to imagine what happened to it given the current rating. Pure speculation but my guess is mechanical damage vs electrical. Any ideas where I can buy one? I could not get through to MSA but maybe I should keep trying. |
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Jim Palenscar
From:
Oceanside, Calif, USA
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Posted 28 Jan 2014 8:06 am
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Lane is accurate- I have those at the shop. I just dug up the NOS pots that I have for MSA and they are 1 meg audio for volume and 1 meg linear for the tone.
Last edited by Jim Palenscar on 28 Jan 2014 9:42 am; edited 1 time in total |
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Alvin Douglas
From:
Prince Edward Island
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Posted 28 Jan 2014 8:37 am
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| PM sent Jim. |
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Alvin Douglas
From:
Prince Edward Island
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Posted 28 Jan 2014 10:26 am
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Done. New pot on the way. Geez, I love this site.
Alvin |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 29 Jan 2014 4:32 pm
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| Lane Gray wrote: |
| 500K mini pot. The Jaw-dropping bit is that it is rated for 5A. |
Pots are normally rated in watts, and the MSA "Classic" pots were quite ordinary - a standard (miniature) commercial version of the MIL type RV8, and rated at 1/2 watt. They had a 1/2" body, and a 1/8" shaft, and those I've seen were 500k, though any audio pot from 250k to 1 meg will suffice. Also, most of them had nylon shafts, which was normal for many commercial pots.  |
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Bill Bassett
From:
Papamoa New Zealand
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Posted 30 Jan 2014 6:31 pm
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| MSA also made parts under contract with the military. Those little aluminum knobs are actually mil-spec, used in some kind of Air Force equipment. Not surprising if those pots are over engineered too. I bypassed my V and T pots years ago but they are still in the guitar. |
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Jim Palenscar
From:
Oceanside, Calif, USA
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Posted 30 Jan 2014 6:34 pm
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| The ones that I got from MSA as NOS pots were Mallory. |
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Lane Gray
From:
Topeka, KS
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Posted 31 Jan 2014 4:45 am
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Donny, I know they usually get rated in watts, but mine clearly have "5A" stamped in 'em. That seemed like a lot of current for a carbon track, though.
_________________
2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects |
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Michael Hummel
From:
Ottawa, Ontario, Canada
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Posted 31 Jan 2014 9:18 am
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I suspect the 5A means something else...in order to get 5A through a 500k resistor, you would need 2.5 million volts. I suppose if you had it turned all the way to one end (zero ohms) then the 5A rating might make sense. But that is certainly not a typical use for a high value pot...
Mike
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MSA Classic 5+4
Too many 6-strings and amps to list |
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Jerry Jones
From:
Franklin, Tenn.
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Posted 31 Jan 2014 3:38 pm
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Probably 'A' for logarithmic taper or a 'B' for linear taper. 
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Jerry Jones |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 31 Jan 2014 4:42 pm
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| Maybe .5A ? ( for 1/2 meg audio?) |
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