Pickit 3 repairable?

jpanhalt said:

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Here's a piece of advice I picked up last week. If you are powering the target from the PK3 using 5V, and the PK3 returns an error for the wrong chip ID, try lowering the voltage to 4.75 or even lower. The 12F683 is known for having that issue. There may be others.

John

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Whey you find something like this please post it to
Microchip hints, bug fixes, and work arounds
also.

Good suggestion.

I was hoping to hear back from dr pepper to clarify his comment:

When you set the vcc to 5v on the pk3 I had the v returned was 4.88, that'll be why then jp, and is probably why the copies also have trouble as they probably chuck out 5v.

Click to expand...

And my response:

I am not quite sure what you are saying. Why would 4.88 Vcc (actual) only affect some chips and not others?

Click to expand...

The hint was given to me by someone on the Microchip forum, and the anomalous behavior apparently affects only a few chips in his experience. Dr. pepper's comment, as I understand it, implies it should affect many chips.

So, is it mostly a PK3 phenomenon or a 12F683 issue? I will post to the Hints and Fixes forum a little later when we know more.

John

dunno if it's pk3 or certain chips but i have a few xxk22 that dont behave with the pk3 unless i use less than 5v, i found out by accident because i thought the psu i swapped to used 5v but the output is actualy more like 4.7v and sometimes a bit lower. i have also had other problems with the xxk22 chips

LG,
What was the specific device number and error code? Were you using the PK3 to power the target or a separate supply? If you reduced the power setting (assuming you were powering by the PK3), did it fix the problem?

The error codes seem to be:

1) Target Device ID (00000000) does not match expected device ID (00000xxx). In my case xxx was 460
2) Err0035 Failed to get device ID

#1 is certainly related to the problem; #2 may be related, but I am not sure.

So far, the affected chips I am aware of that have been reported are:

12F683
16F1938
18F4550 (reported today as an unsolved problem)

John

I do not know if this will help.

A while back I had the PK3 connected to a powered USB hub. The power cord to the hub had failed and the hub was being powered by the PC. The PK3 generated over current and errors.

i will dig out my lab book i was using at the time it will be in there as i write everything down, but i am sure it was from pc powered hub via pk3 i will get the chip numbers

Ok then, I read or heard that the 12f chips had issues with some programmers due to the supply voltage, and I spose I just made an assumption after reading your post jp that the reason why my pk3 didnt output 5v, but 4.8v when you told it to was because of these power supply issues.
Wasnt really based on hard evidence so I could be well wrong.