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[PIC] Trying to fix PICkit3 boards

eagle1109

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Hi,

I've got punch of PICkit3 boards from the lab, of course could be broken from shorts or overvoltage.

So now when testing them, they connect to MAPLAB X IPE, they are recognized but can't connect to the PIC chip. what could be the problem ?

I checked with the DMM most the parts on the boards for any shorts to the ground, what other things I should check ?

20210304_095059.jpg

The board on the right is a working one, but obviously there's no difference with the non-working ones. There's no sign of a burnt or fired stuff.
 

danadakk

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One method, tedious, take a good and bad board side by side and do R
checks to ground of power supply section, then do it for USB section, then
chip.

Powered up using scope compare pins on processor for duplicate activity.

Same can be done for V checks, but you don't have (yet) a viable reference,
eg., are all boards running same code, if running.

If you have the potential for this to happen again include code in all boards
to do a power up looping code that generates a "signature" based on some condi-
tion, like two pins at a state, or a specific V at a pin.....

Regards, Dana.
 

eagle1109

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One method, tedious, take a good and bad board side by side and do R
checks to ground of power supply section, then do it for USB section, then
chip.

This was my first attempt this morning, but maybe because I was going through 5 broken boards, so I may missed concentrating on all test points and strategies.


Powered up using scope compare pins on processor for duplicate activity.

I'm leaving the scope the last attempt, because it's not around right now.

Same can be done for V checks, but you don't have (yet) a viable reference,
eg., are all boards running same code, if running.

The one in the picture on the right with the red circle is actually a working one, and I just did the V checks and found a shorted component but I don't know its name.

This one:

shorted device.jpg

The one on the left is a working board, the shorted device is also causing unbalanced voltages on the surrounding area; e.g. the lm358 and the yellow/black components I'm not sure what they are, diodes/capacitors ?


If you have the potential for this to happen again include code in all boards
to do a power up looping code that generates a "signature" based on some condi-
tion, like two pins at a state, or a specific V at a pin.....

Didn't get what you mean here ?
 

danadakk

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Get a schematic, cant tell what the part is by appearance.


If you have the potential for this to happen again include code in all boards
to do a power up looping code that generates a "signature" based on some condi-
tion, like two pins at a state, or a specific V at a pin.....

This comment is basically putting into application code a fail safe piece of code,
if processor can still run, to help in troubleshooting. Like the appliance guys where
you press two buttons on a machine to force it into a diagnostic mode.

Regards, Dana.
 
Last edited:

Dan1138

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@eagle1109,

All of the PICkit3 pictures in your post#3 appear to be copies of the Microchip PG164130 device programmers.

This is what genuine PG164130 look like:
PK3_10-00424-R2_top_.jpg

PK3_10-00424-R7_top_.jpg

The transient suppressors (TR1,TR2,TR3) in the 10-00424-R2 were damaged so I just removed them to get it working again.

This is not something I would suggest you do but I do not see these parts in your copies. Most likely the transceivers that drive the PGD,PGC and PGM lines are damaged and even perhaps the VPP voltage driver circuit. But the VPP voltage driver circuit is usually a very hard to damage.

It's impossible to tell which components in your PK3 copies are involved in these circuits.

Without an accurate schematic you will need to either trace out that part of the circuit in your clones, or guess what parts are bad, or buy more PIKkit3 clones.
 
Last edited:

eagle1109

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Got this broken yesterday by the same usual mistake which is someone connect the dev board without knowing what is the power supply knob is set to.

The trainee turned the power on and the spark fired on the board, I knew something is fried, I checked it was the PICkit.

boards.jpg


I bought these long ago, I hope they are the right replacement parts.

ic.jpg
 

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