PX1 Power plug was with reversed 12V Polarity. What to replace?

[PinakBERT]

So in another thread I mentioned that I had inadvertently connected the 12V power supply to one of my PX1 in reverse. The LEDs do not respond now when I put the wires from the power supply correctly to the board. Nor does it light up any pixels.

But when I tried to re-program the PIC with the PICKit2 the LEDs came on and it was able to read/Write/verify the pic. So at least that part still works. The fuse is not blown (checked with a multimeter). But the plastic around the fuse looks like it was cracked (kinda like how super glue comes is contact with plastic). I don't see any other physical problems with the board, but what can be replaced to make it functioning again? I will try another fuse to be sure it not that.

thanks

[PinakBERT]

I swapped out the fuse from another working px1 and LEDs still don't turn on.

Any suggestions??

[Barnabybear]

Hi, I would suspect the voltage regulator is dead:

http://www.doityourselfchristmas.com...le:PX1-IC3.jpg

If you measure the voltage with a probe on ether side of C2 what reading do you get?

[PinakBERT]

Hi, I would suspect the voltage regulator is dead:

http://www.doityourselfchristmas.com...le:PX1-IC3.jpg

If you measure the voltage with a probe on ether side of C2 what reading do you get?

I'll give that a shot tonight... I can use my multimeter right?

[PinakBERT]

Hi, I would suspect the voltage regulator is dead:

http://www.doityourselfchristmas.com...le:PX1-IC3.jpg

If you measure the voltage with a probe on ether side of C2 what reading do you get?

When I measure C2 I get 12.16V. Is that good or bad?

[MartinMueller2003]

The voltage going to the CPU must be 5v. Please check the CPU voltage.

[PinakBERT]

The voltage going to the CPU must be 5v. Please check the CPU voltage.

Where do I test that? looking at some schematics and stuff for the PIC. Do I just measure Pins 1 & 14 on the PIC??

[jimboha]

Looking at the PIC with the notch/dimple on the left, then measure between pin 1 (ground, bottom left) and pin 14 (V+, top left).

Jimboha

[joeytx]

On the 16f1825, pin 1 is 5vdc and pin 14 is ground. The dot denotes pin 1. Unless I'm mistaken.

[jimboha]

Yep, but for the purpose of testing his voltage, either polarity will work.

16f1825.jpg

Vdd (drain, ground) is 1. Vss (source, Vdc) is 14.

Or am I having a(nother) senior moment?

Jimboha