Pads Done Come Off...

Coda

Coda

Well-known member
not paying close enough attention, I soldered a pot in upside down. It was hell to remove (new, lead free solder...it’s very sticky, seemingly). Anywho, when I got the pot out, two of the three pads came with it. Is it game over for this PCB? Will it make a difference? Is it fixable?...
 
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Chuck D. Bones said:
Measure the reverse resistance. Then warm it up with your fingers and watch how the resistance drops. Most Germanium diodes are very leaky and the leakage is very temperature sensitive.
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I measured it again and got .266, which is about what I got earlier. I held it between two fingers for a few minutes, and measured again. The numbers went all over the place; from .335 to .1024. Did I do it right?
 
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Reverse the meter leads so that the red lead is on the cathode. Set the meter to measure resistance. If your meter auto-ranges, it will probably bounce round. Find the manual range that gives the highers reading. Now try the touch test again.

Some Schottky diodes are leaky, but not all that temperature dependent. Other Schottky diodes have very low leakage and will read OL on any resistance range.
 
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Chuck D. Bones said:
Reverse the meter leads so that the red lead is on the cathode. Set the meter to measure resistance. If your meter auto-ranges, it will probably bounce round. Find the manual range that gives the highers reading. Now try the touch test again.

Some Schottky diodes are leaky, but not all that temperature dependent. Other Schottky diodes have very low leakage and will read OL on any resistance range.
Click to expand...
Measured in reverse I get OL, with and without finger warmth.
 
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Chuck D. Bones said:
You tried all of the resistance ranges?
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Just re-ran the rest though all settings;

20M: 0.83 (forward), around 5 (reverse)
2000k: 280, OL
200k: 65.7, OL
20k: 14.74, OL
2000: 287, OL
200: OL, OL

When I performed the heat test in reverse voltage, I got OL across the board...except in the 20M setting, which started at 1.3, and climbed to 5.21.
 
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Based on the 20M data, you have either a very low leakage Germanium (unlikely) or a Schottky diode (very likely). If your diode looks like the one in the GPP photo, then I'm confident that it is Schottky. GPP should know better than to sell Schottky and call it Germanium. Those diodes will work ok in that pedal. Some people (I'm one of 'em) prefer Schottkys in the octave section (D1 & D4). D2 & D3 need to be real Ge for the true mojo, doesn't have to be 1N34A. Will anyone hear the difference? Mmmmmmmmaaaaaaybeeeeeeeee.
 
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