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Laurie
Double Platinum Member
Canada
4854 Posts |
 Posted - 02/28/2010 : 09:07:17
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R14 is the current limit resistor for the opamp. Without this, the diodes would try to draw an "infinite" amount of current during clipping.
Anyway, it is righ tin the middle of the signal path. If there is a problem with R14, the signal path will certainly be affected. |
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kelmaur
Gold Member
USA
505 Posts |
Posted - 02/28/2010 : 09:43:47
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quote:
Originally posted by Laurie
R14 is the current limit resistor for the opamp. Without this, the diodes would try to draw an "infinite" amount of current during clipping.
Anyway, it is righ tin the middle of the signal path. If there is a problem with R14, the signal path will certainly be affected.
ok i found a spare resistor just like the one for the mod (same value) and resoldered the new one in and am geting the same thing
intermittent signal..will get a signal very little( not as loud as other parts) then wont get a signal, then will....short?
and the same leg on the new resistor soldered just exactly like the one before...solder bubbled up on the lead adn climbed up nstead of sticking to the pad..other leg soldered fine
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 02/28/2010 : 17:35:26
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| Can you take a high-res closeup of the area? |
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zentropa
Gold Member
USA
837 Posts |
Posted - 02/28/2010 : 20:29:01
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quote:
yes...some will stick to the pad, but not too much..it balls up and seems like it rises to the top of the lead and some sticks to the pad
you likely overheated the joint and scorched the pad. if you have a small piece of wire you will probably have to solder that wire to the leg of the resistor that isn't coming into contact with the pad and solder the other end of the wire to the joint that should connect to that leg of the resistor via the traces. |
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kelmaur
Gold Member
USA
505 Posts |
Posted - 02/28/2010 : 23:03:12
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quote:
Originally posted by zentropa
quote:
yes...some will stick to the pad, but not too much..it balls up and seems like it rises to the top of the lead and some sticks to the pad
you likely overheated the joint and scorched the pad. if you have a small piece of wire you will probably have to solder that wire to the leg of the resistor that isn't coming into contact with the pad and solder the other end of the wire to the joint that should connect to that leg of the resistor via the traces.
any particular gauge of wire? |
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zentropa
Gold Member
USA
837 Posts |
Posted - 03/01/2010 : 00:25:39
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quote:
any particular gauge of wire?
i've only done it a handful of times during pedal repairs, usually after a pedal was reverse voltaged and blew the protect diode which ended up scorching and peeling up the traces on the board.
i used like 26 gauge solid wire, but i'm guessing most things will do the trick (although i'm not sure if braided wire would do as well).
what's happening is that the pad is probably peeling up from the traces and will not longer bond with the solder. that is causing a short, since it's the pad which basically connects the component to the circuit, you'll just need to wire it point to point instead of using the traces on the board. |
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kelmaur
Gold Member
USA
505 Posts |
Posted - 03/01/2010 : 01:56:11
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quote:
Originally posted by Laurie
Can you take a high-res closeup of the area?
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kelmaur
Gold Member
USA
505 Posts |
Posted - 03/01/2010 : 02:00:18
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that is the new cap...getting ready to desolder it and guess i should get pics up of the pad...didnt think about that till after i posted the other pics
see how the solder balled up on the one leg
and yes i noticed something wrong with the trace... |
Edited by - kelmaur on 03/01/2010 04:44:46 |
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kelmaur
Gold Member
USA
505 Posts |
Posted - 03/01/2010 : 02:26:34
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here are the pics showing the pad, after i took out the new resisitor i put in
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kelmaur
Gold Member
USA
505 Posts |
Posted - 03/01/2010 : 02:35:43
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zentropa
Gold Member
USA
837 Posts |
Posted - 03/01/2010 : 05:18:19
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yah, that pad is definitely scorched. the burn marks on the top side of the board = bad.
i'm not sure where the wire would connect on that one... probably just back to the other leg of the resistor. i'd wait for someone who's better than me at this stuff to chime in first. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 03/01/2010 : 05:25:39
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| Hey... before we go too much further, can you post a pic of your soldering iron? |
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kelmaur
Gold Member
USA
505 Posts |
Posted - 03/01/2010 : 05:33:01
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quote:
Originally posted by Laurie
Hey... before we go too much further, can you post a pic of your soldering iron?
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 03/01/2010 : 06:10:54
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Righto. Just wanted to see what advice to give about soldering - depends on size/heat of the iron.
If it isn't resolved by then, I'll take another look at the symptoms tomorrow night after work.
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zentropa
Gold Member
USA
837 Posts |
Posted - 03/01/2010 : 06:20:25
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| So would jumpering the legs together on R14 solve the break in the circuit? |
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Topic |
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No signal (seeing eye mod DS-1) My first Mod
