reverse polarity on sbc65

[eagleeye]

Hi
 I got some board where users plugged in DC voltage
with reverse polarity..

I checked the 7805 its working.. Any ideas on
what components to change to get it working again?
The board wont power up

Allan

[Phil Wieland]

If you mean reverse polarity at the power socket, then D1 provides protection and I would be very surprised if there was any damage.  

If the reverse power was applied to Vcc, perhaps via the daughter board connector, then it could be any or all of the semiconductors damaged.  Ouch!

[nikosxan]

Hello

Taken into account the IC's and pin number i'd say go for a new board. It's almost impossible to properly unsolder / solder new PIC for eg in such small board, if you don't have the proper equipement and in most cases it isn't worth it.

However if volatage was throught the board connecter there's always D1 as said before.

Bye

[eagleeye]

OK I guess if you reverse polarity on the BOARD ALONE it may be ok.
Howeve the board was hooked up to the IOR5E and all the A/D wiriing
was all connected.   so anyway we already had 2 cases of this..

Its too expensive to try to find out why.. I've designed some
KEYED wiring system to keep users from plugging things backwards.

Allan

[nikosxan]

Putting some H/W to prevent reverse polarity is OK. Still i think for such a circuit (complexity versus price versus board size & design) the way to go is buy a new one if it fails.....The equipement to replace one of the major ICs (PIC, RTL) and job required is that much that only leads to complete replacement.........