PICKIT Troubleshooting/repairing

[sanju sanju]

Hi everyone I'm new to PIC. I brought an USB programmer(PICKIT 2 CLONE MAde in India). It was working quite well but there was an Accident, I accidently shorted ICSP pins. Now the Kit is showing VPP error. The chip18F2550 in the kit is fine. when I troubleshoot with PICKIT 2 v2.61, It says VDD short. Can anyone help me to correct it. I have posted tthe circuit diagram of my PIC Programmer.
Please help me to troubleshoot the problemView attachment 66802
The Pickit physically looks like this
View attachment 66803


Kindly help
Thanking in anticipation

 

[kyru27]

Do you know which pins did you shorted?

Have you checked Pickit 2 programmer-> Troubleshoot to know in a better way what it's failing?

I've never seen a Vpp voltage problem, if it's a Vdd one I've managed to solve it by inputting external 5 V.

 

[upand_at_them]

Did you try rebooting everything? Did you try another target chip/circuit?

 

[mvs sarma]

Try to check and if needed replace the Q2(2n3904). this is expected to ground the Vpp wire under PIC control thro the 100 ohm resistor. if Q2 developed a leak or short, you might get that message

 

[sanju sanju]

The transistors are fine !

 

[sanju sanju]

The first three pins i.e, Vpp Vss Vdd by a needle.
this was done by my friend who didn't have the idea of kit and μcontroller

 

[Ian Rogers]

RA0 detects the VDD... What is the voltage at the junction D1 & C1?

 

[sanju sanju]

And there is 1uF Capacitor(Elecrolytic) between PIN15 and Ground. ( DIAGRAM
NowView attachment 66813)

regretting for the error

 

[sanju sanju]

When I connect it with my PC the Red Light blinks and there is a voltage rise upto 9.71Volts and then there comes error message popping up(Vpp ERROR) and voltage falls below 3V

 

[mvs sarma]

the programmer worked well
so values wont matter
,
but possible some component is faulty. i wonder whether you tested the T2(Q2) by taking it out or while in circuit? at times we miss, to judge the leakage
Anyway, you may reload the firmware by using pickit2v2.61. You can find the firmware in mplab at pickit2 folder

 

[sanju sanju]

When I connect it with my PC the Red Light blinks and there is a voltage rise upto 9.71Volts and then there comes error message popping up(Vpp ERROR) and voltage falls below 3V

 

[sanju sanju]

thanks for the reply sir,
Do you mean Downloading PICKIT 2 OS?

 

[mvs sarma]

i meant
you can find the firmware here
follow link
C:\Program Files\Microchip\PICkit 2 v2
there is a HEX file
and that is where you have to point the pickit2 driver under 'Tools'-'pickit2 download operating system'.

and this is the path
C:\Program Files\Microchip\PICkit 2 v2

 

[sanju sanju]

the programmer worked well
so values wont matter
,
but possible some component is faulty. i wonder whether you tested the T2(Q2) by taking it out or while in circuit? at times we miss, to judge the leakage
Anyway, you may reload the firmware by using pickit2v2.61. You can find the firmware in mplab at pickit2 folder

Respected Sir,
I did it soon after I got my ICSP shorted(Accident), I checked all the components, The IC is fine. (I borrowed another PICKIT Clone from my friend and replaced His IC with mine in his PICKIT) and I have replaced the transistors with new ones. Then one of my senior told me to replace BAT48 schottky diode. I did the same, only to loose Rs50. still the same problem



Requesting further Help
I sincerely thank you from the bottom of my heart for everyone who took pain to help me!

 

[mvs sarma]

afterall a schottkey diode like 1N5819 costs Rs5/-of course to and fro petrol charges to shopping

ok sending pm sanju sanju

 

[sanju sanju]

Let me tell you my basic understanding of PICkIT 2 clone which I have posted.

The Inductor, D1, C1 1n4148 and Q1 constitute Boost Regulator(+5V to +12V) and the voltage feedback is given to RA0 via voltage divider R8-R5. R15 and R6 are regular current limiters for PGD and PGC and R3 and R4 are Pull downs. The green LED is the power LED and Red LED is the "BUSY" LED. and this clone doesn't have READY/Wait(usually Yellow). the Q4 triggers the PNPQ3 and Q2 is pulldowns Vpp via 100Ω. and the rest of circuit I don't understand



Please Help me to understand working of the PICKIT!

 

[mvs sarma]

while on pickit2 software, click help and click user manual. try to go thro and it is exhaustive

is your sch written correctly?
R1 should be 1k
R5 and R8 values found interchanged.
R15 and R6 should be 33 ohms
R3, R4 should have been 4.7K and not 47K.
C1 could be just 47uF
the cap on pin15 could be low at 0.47uF, a disk or box cap.
may i suppose that the errors crept in while copying the diagram from the pcb?

 

[sanju sanju]

Thank You Everyone for helping me for repairing my PIC Programmer Kit.

With Guidance and Blessings of ALMighty and MVS Sarma I was able to achieve the task.

The Problem was VPP Error and It was solved by replacing a new 150 uH Inductor at old one in the Vpp stepup(5V - 12V boost converter or step up chopper).



Thank you Everyone for Aiding me with your Knowledge and spending Valuable time to post in this forum.

 

[mvs sarma]

perhaps it was more due to your hardwork, patience to attack the fault.
all the best to you.

 

[sanju sanju]

Its your great heart that you congragulate me but I did nothing. I did what You said sir!


My sincere thanks from the bottom of my Heart Sir !

May GOD shower you with Great Health, Happiness and Peace of mind
My Prayers with you sir

Thank You

SANJU SANJU