2 cheap old PSUs

Thread Starter

kellogs

Joined Aug 13, 2017
7
From the first one:

20221226_025309.jpg

I am able to stick a needle all the way down. What might have happened here ?

Second PSU:


20221228_203500.jpg

20221228_211850.jpg

20221228_211337.jpg

20221228_211353.jpg

20221228_210717.jpg

That maroon stuff made me cough a bit upon pulling the parts out with a hot air gun. It does not look to me that it has come out of the caps. DMM readings on the scorched 220k resistor are all al over the place depending on scale. Replace resistor only ? And how did it happen I wonder...

Thanks
 

dl324

Joined Mar 30, 2015
16,943
I am able to stick a needle all the way down. What might have happened here ?
Why did you stick a needle in the hole? Those capacitors are rolled up plates/dielectric. It's more typical for the scored vent on the bottom to pop, but it could be possible that a short caused a localized hot spot that made the hole.
That maroon stuff made me cough a bit upon pulling the parts out with a hot air gun.
Why are you using a hot air tool on through hole parts? You have better control of where the heat goes with a soldering iron.
It does not look to me that it has come out of the caps.
Does it matter?
DMM readings on the scorched 220k resistor are all al over the place depending on scale. Replace resistor only ?
Obviously you need to replace all of the components you identified as defective, but that's not a guarantee that it will fix the problems.
 
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