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Dr. Bob
Moderator
Australia
6593 Posts |
 Posted - 02/20/2008 : 13:53:01
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Hi Goran & Guys
Just been thinking about how to do a quick test, to see if the pot-s is-are working.
What about temporarily wiring in a 22k & a 33K resistor in series,
Then connecting the junction to where the middle lug on the pot is
and the other two ends of the resistors, one each to the outer lugs.
OuterLug--/\/\/\--MiddleLug--/\/\/\--- OuterLug
I hope you can understand my simple text Schematic.
This will act a fixed substitute pot.
you can then test if the TW-1 is actually working.
Or you could also make a 10K & 39K in series, & do the same.
You can use any two resistors that approximate the value of the pot.
I do this when I don't have the correct value pot & I'm trying to repair something, until I can get the correct part.
I was also thinking if the other pot may have been damaged as well?
Just my 2 cents worth.
Good luck Goran
Regards Dr. Bob |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 02/20/2008 : 13:54:59
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Hi Goran & Guys
I forgot to say, while you are at it, test the switch as well.
Is there power getting to the board?
I just noticed that there are 3 different op-amps used in the TW-1
Which one-s are used in your one Goran?
Regards again Dr. Bob |
Edited by - Dr. Bob on 02/20/2008 13:56:56 |
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ChristoMephisto
Platinum Member
Canada
1288 Posts |
Posted - 02/20/2008 : 14:19:09
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Neato, didn't know there were two versions of the TW1,
the older ones had the 3034 SIP opamp, same as the older OD1s.
The online schems only show the 2x4558 opamp versions. |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 02/20/2008 : 15:08:23
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Hi Christo & guys
I know the RC3403A came in a 14 pin DIL package, but I'm not sure if it came in a SIP
DIL - Dual Inline, like most common IC's.
SIP - Single Inline Package, legs only on one edge & made to stand upright.
Christo, do you have the datasheet for the 3403's?
Maybe some other member has the Schematic & service notes for the early Touch wah's with the RC3403's
Regards Dr. Bob |
Edited by - Dr. Bob on 02/20/2008 15:09:14 |
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Goran
Double Platinum Member
Sweden
2203 Posts |
Posted - 02/21/2008 : 06:58:52
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quote:
Originally posted by Dr. Bob
Hi Goran & Guys
Just been thinking about how to do a quick test, to see if the pot-s is-are working.
What about temporarily wiring in a 22k & a 33K resistor in series,
Then connecting the junction to where the middle lug on the pot is
and the other two ends of the resistors, one each to the outer lugs.
OuterLug--/\/\/\--MiddleLug--/\/\/\--- OuterLug
I hope you can understand my simple text Schematic.
This will act a fixed substitute pot.
you can then test if the TW-1 is actually working.
Or you could also make a 10K & 39K in series, & do the same.
You can use any two resistors that approximate the value of the pot.
I do this when I don't have the correct value pot & I'm trying to repair something, until I can get the correct part.
I was also thinking if the other pot may have been damaged as well?
Just my 2 cents worth.
Good luck Goran
Regards Dr. Bob
A very good idea Dr Bob!
But my pot is working, I know it as I measured it.
But I have another 50K pot I will solder in and see if things change for the better.
I have been busy modding my Valve Junior for a while now and TW-1 has been forgotten.
There is power on the board too, the pedal do make something to the sound, but not auto wah.... It�s more like a wah in fixed position. |
Edited by - Goran on 02/21/2008 07:00:33 |
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Repairing pots?
