Author Topic: No power on just finished assembly

June 05, 2023, 11:03:59 AM
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muldee

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Hello everyone, I have a problem with my MP573. Right after finishing the assembly, I started the setup process which ended very soon right after the point number 3. When I check voltage between TP2 and V+ I read zero. It seems that the unit is not getting any power from the lunchbox (a Midas Legend L10). I checked the lunchbox and it is fine. I also removed all the other 500 units from it to verify if the issue is there.
I'm still checking the MP573 for any short or cold soldering, but I'm not able to see one by now.
Can anyone suggest me what can be the possible faulty piece or point me in the right direction of investigation so I can try to solve the issue?
Thank you so much.

June 06, 2023, 06:13:43 PM
Reply #1

JPK

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What DC voltage do you get between the 0V test pin and TP2?
What DC voltage do you get between the 0V test pin and the V+ pin?
Check that you didn't swap U1 and U2.
Check that D3, D4 are in the correct direction.
Check the solder joints on D3, D4, PTC1, U1, U2.
JPK

June 15, 2023, 05:26:07 PM
Reply #2

muldee

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I am definitely going blind. It was the damn D4 mounted in reverse. I fixed that and now the unit works like a charm.

Thank you so much JPK.