Dead Prop 1

[Jadams]

My Prop 1 died after I hooked up a PIR to the header pin 'without' turning off the power.  The power light in position 1 went out.  I replaced the 2803 with a known good one, still nothing.  Did I fry it?

[JonnyMac]

You might have killed the regulator if you plugged the PIR in backward or shorted the 5v rail to ground in the process.  Disconnect everything, apply power, and move the power switch to P2 -- if the V+ LED lights but not the normal power light then the regulator is done.

[Jadams]

With the power switch to P2, V+ lights.  Can I replace the regulator if I can find one?  It looks to be a LM2940.

Thanks

[JonnyMac]

Yes; carefully -- the regulator body can absorb the heat from your soldering iron so I off the regulator before attempting to de-solder the leads.

The part is an LM2940-5.0, LDO regulator.  In a pinch you can us an LM7805 that's available at RadioShack.  I buy my electronic parts from Mouser.com; the Mouser part # for that regulator is 821-TS2940CZ50.

[Jadams]

Thanks Jon,

I have a 7805 in my spare parts box, I'll give it a try.  I think I'll order a couple of 2940's for the next time I do something so stupid.

[Jadams]

The 7805 works, I'm back in business.

Thanks

[JonnyMac]

That's good news.