# Do diodes leak or go bad?



## Granny Gremlin (Jun 3, 2016)

... or is this just some flux residue?


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## JeremyP (Jan 10, 2012)

I was always under the impression they rarely fail unless hit the wrong way with too high voltage. Then if that happened they should stop functioning . So you would know it was pooched.....I always thought that was why you put a protection diode in front of a pedal circuit so if you put the wrong polarity in it doesn't fry anything Other then the diode haha.


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## Latole (Aug 11, 2020)

Look ok ,
Is output voltage is ok or not ?

Why not test them ? So easy.
As I see in your picture, you don't need to desolder them. Check in circuit,


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## jb welder (Sep 14, 2010)

They don't leak. They can go bad but won't do that if they go bad.
That looks like flux residue. Likely the board was hung upside down at the factory, with all components stuffed, for soldering. So flux could have run down the lead to the component body.
Solder from that era seems like it had more flux, you see a lot of it in Traynor products from around that time (when those green diodes were in use).


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## Paul Running (Apr 12, 2020)

Yeah, they usually remain solid-state, until 1400°C...that looks like rosin flux.


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## Lincoln (Jun 2, 2008)

I encountered a new diode that was born bad. It passed in both directions, really messed me up for a bit. 

Now I test new diodes before installing them. I also test resistors, because it's been proven I can't tell the difference between 470R and 470K.


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