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Topic: Model 6A Goodrich Matchbox problems |
Virgil Franklin
From:
Indiana, USA
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Posted 18 Jun 2024 9:27 am |
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Model 6A Goodrich Matchbox problems:
No volume/ gain until 8 and then just distortion..
any ideas?
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Virgil Franklin
Organizer: Southern Indiana Steel Guitar Show www.southernindianasteelguitar.com
2023 Justice Pro-lite 4 x 4,2020 Justice Pro-Lite 4 x 4 , S10 1977 Dekley 3x3, Stringmaster Mk1 Clone, Gibson Console Grande 520, Boss Katana 100 Mk2 with Basslite 2012 speaker |
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Tucker Jackson
From:
Portland, Oregon, USA
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Posted 18 Jun 2024 9:26 pm
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Hi, Virgil.
Maybe it needs a fresh battery?
It's always a good idea to try out some different cables too. |
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Virgil Franklin
From:
Indiana, USA
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Posted 19 Jun 2024 2:52 am
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Absolutely...
Change of batteries... cables..then ..changed out gain pot..
_________________
Virgil Franklin
Organizer: Southern Indiana Steel Guitar Show www.southernindianasteelguitar.com
2023 Justice Pro-lite 4 x 4,2020 Justice Pro-Lite 4 x 4 , S10 1977 Dekley 3x3, Stringmaster Mk1 Clone, Gibson Console Grande 520, Boss Katana 100 Mk2 with Basslite 2012 speaker |
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Mike Auman
From:
North Texas, USA
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Posted 19 Jun 2024 7:28 am
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Virgil, if you've changed the gain pot, then the likely culprit is the op amp, I've seen one fail in a 6A. If it looks similar to this, the part number is Motorola MC33171, hopefully Goodrich mounted it in a socket like here, so you can just pop it out rather than desoldering.
Here's a source for the op amp: https://www.mouser.com/ProductDetail/511-MC33171DT
This replacement is a surface mount part (suffix DT), they don't make the original DIP thru-hole version any longer (suffix P), so you'll need an adapter like this, it matches the new part to the old circuit board: https://www.mouser.com/ProductDetail/910-PA0001 .
All you need is about $15 for parts and shipping from Mouser, and a steady hand for soldering small leads. Here's what the fix looks like on a newer 6A, with the replacement op amp and adapter board:
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Long-time guitar player, now wrestling with lap steel. |
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Virgil Franklin
From:
Indiana, USA
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Posted 19 Jun 2024 9:05 am
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Thank you so much.Appreciate greatly, but unfortunately, this one looks like it's pre Op amp IC and uses three transistors so i'm back to checking the transistors to see if one of them is not happy..
_________________
Virgil Franklin
Organizer: Southern Indiana Steel Guitar Show www.southernindianasteelguitar.com
2023 Justice Pro-lite 4 x 4,2020 Justice Pro-Lite 4 x 4 , S10 1977 Dekley 3x3, Stringmaster Mk1 Clone, Gibson Console Grande 520, Boss Katana 100 Mk2 with Basslite 2012 speaker |
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Mike Auman
From:
North Texas, USA
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Posted 19 Jun 2024 10:57 am
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Agreed, I would just change them one at a time.
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Long-time guitar player, now wrestling with lap steel. |
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Virgil Franklin
From:
Indiana, USA
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Posted 23 Jun 2024 6:43 pm
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They are a very common transistor.. availble for pennies a piece...
MPSA18
_________________
Virgil Franklin
Organizer: Southern Indiana Steel Guitar Show www.southernindianasteelguitar.com
2023 Justice Pro-lite 4 x 4,2020 Justice Pro-Lite 4 x 4 , S10 1977 Dekley 3x3, Stringmaster Mk1 Clone, Gibson Console Grande 520, Boss Katana 100 Mk2 with Basslite 2012 speaker |
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