Boost convertor not boosting = outputting input voltage

Thread Starter

joachym

Joined Feb 21, 2022
20
Hi all,

I bought a boost convertor and replaced the potentiometers with connectors to be able to place it into a nice box. Then I forgot to connect the potentiometers and killed it... I bought a new one and destroyed it in a very similar fashion. The last one had been delivered today and died a few hours later - the same reason, but this time "I made everything properly" :(.

Do you have any tip "what could be destroyed"? Is it the control chip, or possibly just any diode or whatever? I am thinking about repairing it but my skills are insufficient for diagnosis... Is there any "prime suspect" to focus on?

Thank you for any advice!

BR,
j
 

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BobTPH

Joined Jun 5, 2013
8,921
Are you sure they are destroyed? It should not be that easy. How are you testing them?

Edit to add: My best guess is reversed polarity on the input.
 

Thread Starter

joachym

Joined Feb 21, 2022
20
Are you sure they are destroyed? It should not be that easy. How are you testing them?

Edit to add: My best guess is reversed polarity on the input.
They are not "dead", only outputting input voltage - "not boosting". I bought two of them in this last round and the second piece still works properly so I am positive that reverted polarity is not the case. I suspect "bad connection" of the potentiometers (almost certainly in the first two kills) - that should be the clue as for what could be possibly damaged...

Thanks!
 
Last edited:

BobTPH

Joined Jun 5, 2013
8,921
Please post pictures of the unmodified board and the board with new pot showing the connections. Show markings in the two pots.
 

Thread Starter

joachym

Joined Feb 21, 2022
20
Hello guys,

I spent 35 minutes precisely describing my issue when... power outage struck (bad weather). So I went to my "workshop" to try "troubleshoot" and I realized that it works. Due to potentiometer in the left most position it limited current (although no load connected) by lowering the voltage. After "allowing more current" the voltage rose properly. Really dumb mistake :(

Thank you very much for your readiness, much appreciated. Next time I will bring better problem - I am a very good source of them...

Best,
j.
 

Thread Starter

joachym

Joined Feb 21, 2022
20
Damn, I almost suggested that.
Don't worry, your comment "It should not be that easy." made me doubtful. In my experience, it actually IS very easy for me to destroy things :(, but you made me think "what and why" would have been destroyed... Not claiming that I found the "non-issue" using engineering - it was pure coincidence - but the device also might have already been disassembled (my hands are sometimes quicker than my thoughts :().
So, thank you for your contribution anyway!
 

BobTPH

Joined Jun 5, 2013
8,921
Don't worry, your comment "It should not be that easy." made me doubtful. In my experience, it actually IS very easy for me to destroy things
What I meant by that there are usually some obvious symptoms, like overheating or smoke when you destroy electronics, and that did not seem to be the case here.
 
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