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electronics question

iskim86

iskim86

Banned
I located a broken diode on my guitar effects pedal... it was an 1N4003, but there's an "L" or a "1." behind the digits (it's kinda hard to see).

anyway I desoldered the broken diode off the circuit board, and soldered a new one on it (it's probably the correct one) and I gave it some power and I could smell something burning... and it turned out the diode got hot as hell and stuff, almost burning through the PCB and stuff. wtf? what did I do wrong? it's the right diode and all.....

does it matter which direction diodes face?
 
Yes, direction is important, congrats on burning the diode....hehe

You probably saturated it the by putting it in the wrong way.
 
Also make sure you have a 4003 as your replacement. The difference between the diodes in the 4000 series is the peak repetitive reverse voltage across the diode. A 4003 can take a higher reverse voltage than the 4001 and 4002 so make sure you replace it with a diode that has the same tolerances otherwise you'll burn it out the same way when it suffers reverse breakdown.
 
ok so coldered a new diode onto place in the right direction. when I give it power, it lights up, which is an indicator that circuit is complete, right? but I don't get any audio signal through.... weird. can a wrong diode do this?
 
Originally posted by: iskim86
ok so coldered a new diode onto place in the right direction. when I give it power, it lights up, which is an indicator that circuit is complete, right? but I don't get any audio signal through.... weird. can a wrong diode do this?
Click to expand...
Installing a diode reversed can cause damage to other components - it was in there that way for a reason. You may need to find a good technician.
 
Originally posted by: CallMeJoe
Originally posted by: iskim86
ok so coldered a new diode onto place in the right direction. when I give it power, it lights up, which is an indicator that circuit is complete, right? but I don't get any audio signal through.... weird. can a wrong diode do this?
Click to expand...
Installing a diode reversed can cause damage to other components - it was in there that way for a reason. You may need to find a good technician.
Click to expand...

when I opened it up, the diode that needed replacing was literally broken in half. what can cause this?
 
Originally posted by: iskim86
ok so coldered a new diode onto place in the right direction. when I give it power, it lights up, which is an indicator that circuit is complete, right? but I don't get any audio signal through.... weird. can a wrong diode do this?
Click to expand...

It is quite possible there is another problem other than the diode. When you found the broken diode was it burnt in half or just broken?
 
Originally posted by: IamElectro
Originally posted by: iskim86
ok so coldered a new diode onto place in the right direction. when I give it power, it lights up, which is an indicator that circuit is complete, right? but I don't get any audio signal through.... weird. can a wrong diode do this?
Click to expand...

It is quite possible there is another problem other than the diode. When you found the broken diode was it burnt in half or just broken?
Click to expand...

broken in half, revealing the shiny stuff inside
 
Originally posted by: iskim86when I opened it up, the diode that needed replacing was literally broken in half. what can cause this?
Click to expand...
A diode may break in two because it shorted - the concentrated heat cracks the case. Get a DMM and look for a shorted capacitor or other component downstream from the diode. Or find a good tech who works cheap - a case of good beer can work wonders.
 
Originally posted by: CallMeJoe
Originally posted by: iskim86when I opened it up, the diode that needed replacing was literally broken in half. what can cause this?
Click to expand...
A diode may break in two because it shorted - the concentrated heat cracks the case. Get a DMM and look for a shorted capacitor or other component downstream from the diode. Or find a good tech who works cheap - a case of good beer can work wonders.
Click to expand...

i see. the diode is the first in the circuit (i think?)... it's located right next to the power supply jack and the center connector heads right to the diode.
 
AC or DC input? If it's AC, the diode is there to turn it into DC (after filtering). A shorted filter cap could be what killed your original diode.
 
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