Reverse voltage on DC/DC

[johnny_cash]

Hello everybody,

I have a trouble: basically, i have an isolated DC/DC converter (VIN/VOUT), "plug'n play (no external components required). DS: http://www.murata-ps.com/data/power/ncl/kdc_mee1.pdf

primary: +5v/GND1 which should go to Vin+/Vin-
secondary: Vout+/Vout- that shoudl provide +3.3v/GND2

unfortunatly, my PCB is badly wired: +5v/GND1 to VIN-/VIN+ and VOUT+/VOUT to GND2/+3.3v; Totally reversed on both input and ouput.

I have no skill in unsoldering the DC/DC. However, to continue my job, could i simply power the secondary, without having my primary powered ? It would imply to have +3.3v on VOUT- and GND2 on VOUT+ on secondary side of the converter.

I know this is not something good, but can it be possible or would it definitively harm my converter (and impact the primary side of the board) ?

Thank you for you advices, JC

 

[BobK]

It would be safer to cut one of the traces from the DC / DC, isoltating it from the supplied voltage.

Bob

 

[johnny_cash]

thank you for this advice. Unfortunatly, i think the traces are on layers 2 & 3. Do you think:
- it could harm the primary
- it could harm the DC/DC

I always heard theses beasts are rock solids...