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Topic: Goodrich 7A matchbox pot |
Larry Dering
From:
Missouri, USA
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Posted 10 Dec 2021 12:03 pm |
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I'm trying to fix scratchy pots and the gain pot is a 500K 1 watt mod pot. Body is square and small. There's no room for a bigger pot without modifying the contents. I can't find this Clarstat pot, its obsolete.has anyone modded this or used a different part in its place?
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Cartwright Thompson
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Larry Dering
From:
Missouri, USA
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Posted 10 Dec 2021 3:26 pm
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| Thanks but those are only 1/4 watt .25 It has a 1 watt pot. Since this is used as a resister I'm not sure of the current requirements. I could unsolder and test but I'm betting it needs more. I found a few square body 1/2 watt pots. Appreciate your help. Still looking. |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 10 Dec 2021 7:07 pm
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| No, you don't need a 1 watt pot, as current drain in the circuit is just a few milliamps. They stopped making that pot about 30 years ago, but any pot that is the same size and value will work identically and reliably in the circuit, and there are plenty of small-form 500k pots available on Ebay. |
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Larry Dering
From:
Missouri, USA
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Posted 10 Dec 2021 7:28 pm
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| Well Donny that is a little good news. I know most circuits use 1/4 watt. The new 7A matchbox appears to be the same size, so either they relocated the parts for a bigger pot or the components are different. I am still suspicious of the current draw and plan on testing for my own satisfaction. I attempted to put a 16mm pot in it's place but I need something smaller yet. |
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kevin ryan
From:
San Marcos, California
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Posted 11 Dec 2021 1:55 pm
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| What Donny said is true. |
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Larry Dering
From:
Missouri, USA
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Posted 11 Dec 2021 4:01 pm
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| Thanks Kevin. I'm looking for a mini pot smaller than 16mm. Still not an easy find. If the location was a bit closer to the battery it would be no issue. That or taller standoffs on the circuit board. I will get it sooner or later. Everything has to be ordered online these days. No local supply. |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 11 Dec 2021 7:37 pm
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An RVC6 pot is a little under 13mm (about .510"). That's even smaller than the stock pot installed in your unit. Of course, they have a 1/8" shaft, so you'll have to get another knob, or install a bushing in your present knob.
Plenty of them available on Ebay. |
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Larry Dering
From:
Missouri, USA
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Posted 11 Dec 2021 7:50 pm
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| Thanks Donny I will look into it. If its 13mm it should fit. |
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