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Topic: Internal pictures of Goodrich 4A Match Box |
Benton Allen
From:
Muscle Shoals, Alabama, USA
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Posted 17 Jul 2009 12:16 pm |
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I recently acquired a non-working Goodrich 4A. Someone has been inside of it and altered the wiring. Since there is no schematic available, could someone that has an old Goodrich Model 4A please open it up and either post or email me a couple of pictures? I would greatly appreciate it.
Thanks,
Benton |
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Benton Allen
From:
Muscle Shoals, Alabama, USA
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Posted 18 Jul 2009 10:52 am
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| TTT Please! |
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Peter Freiberger
From:
California, USA
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Posted 18 Jul 2009 11:35 am
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| Why not post some pictures of your Matchbox as it is. Maybe someone can tell you how to correctly rewire it. |
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Kevin Hatton
From:
Buffalo, N.Y.
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Posted 18 Jul 2009 6:15 pm
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| Oh Pete. That is smart. |
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Bob Lawrence
From:
Beaver Bank, Nova Scotia, Canada
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Posted 19 Jul 2009 6:56 pm I have a few notes from more than 10 years ago
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Benton,
Like Kevin suggested, post your pictures and we can probally figure it out. I have a few notes from when I had one apart years ago but
*** don't change anything based on my info yet, it may not be 100% correct. Lets see what you have first.***
=====================================================
Parts:
MPS6571 Transistor * 2
R1 = 100Kohmes (5%) resistor - Brown Black Yellow
R2 = 2.7 Mohmes (5%) resistor - Red Volite Green
R3 = 10 Mohmes 5%) resistor - Brown Black Blue
R4 = 560Kohmes 5%) resistor - Green Blue Yellow
R5 = 130Kohmes (5%) resistor - Brown Orange Yellow
.047 uf Capacitor * 3 - (cap)
1 meg - ohm * 2 - (variable resistor)
Jacks * 2 (input , output)
Batterys * 2 - 9V
====================================================
Wiring:
View 100k resistor on the left
---------------------------------------------------
............................................Red
..Red
..Black
..............Green.............yellow
......................................Black
.........White
----------------------------------------------------
Input jack - One side to ground and one to a green wire that goes to (2) .047 caps
Power:
+ 18v ------- > 560k resistor
+18 V -------> MPS6571 collector
Output Jack -
.047 cap leg to one side of the 1 meg Pot The other side of the 1 meg pot goes to ground
The center of the pot goes to the output jack (blue wire)
Other:
Black wire to Ground on the board(near the mounting hole) |
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Benton Allen
From:
Muscle Shoals, Alabama, USA
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Posted 20 Jul 2009 8:36 pm
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Unit is now repaired and working as intended.
Bob, the MSP6571 transistors you mentioned were used on units with the BRC-2 circuit board. My unit has the BRC-3 board and uses a TI091CP IC instead. (I didn't know there was more than one type of Model 4A) Some of the wires had been removed and I needed to figure out how it was wired. After locating the data sheet for the TL091CP, I sat down and drew a quick schematic of the unit and was then able to understand how it should be wired. Works great now!
Thanks for your input.
Cheers!
Benton |
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Bob Lawrence
From:
Beaver Bank, Nova Scotia, Canada
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Posted 21 Jul 2009 4:06 am Tl091c - Jfet Input Operational Amplifiers
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Benton,
Re: My unit has the BRC-3 board and uses a TI091CP IC
Did you mean:
TL091C - JFET INPUT OPERATIONAL AMPLIFIERS - Texas Instruments
Anyway great! that you got it going. You should post the schematic. If yo do I'll put it on my steel guitar tech website .
Bye the way my ham call is VE1RLL
Bob
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