Hi all, I have an unexplainable problem with the JDM programmer. I bought a PIC16F84A and after looking at different programmers I decided to build the JDM programmer.

First when I build it there was no response, I couldn't do anything with it, so I checked every connection and found a diode that wasn't soldered well. I fixed that and using IC-prog still I couldn't program anything. I was trying with a hex file that I downloaded. I did the hardware test in Ic-prog and it seemed ok except that the voltage was 5.30V instead of 5V. Then I tried WinPic800 and there I say where was the location of the error. It wasn't on 0x0000 but somewhere further away. Trying different hex file produced different error on another location. Then I made a test hex file with words ranging from 0x0000 to 0x15FF and I hoped to find some pattern in the errors. But, trying different ranges of words results in different errors. Like if I try words from 0x0000 and on, an error occurs on the 0x0010 location, but if I try words starting from 0x0010 and on, I get error on another location. Same error in IC-prog. Changing the delay changed the error locations but still it can not be programmed fully. I can program the pic with some words or if I fill the buffer with the same word(any word). Also I can read it and erase it with no problem.

I tried the same things on two PC's. one with Core2Duo processor and WinXP and the other with Celeron 433 with Win2000 and Win98. I tried it on the two PC's and on 3 OS's with IC-prog and WinPic800 and same error everywhere.

Than I took new parts for the programmer and started changing them one by one and check for changes at every step. I changed the two capacitors, the two transistors and few diodes and there was a difference but still there were errors at different locations.

Can anyone tell me what's the problem? Maybe the PIC is no good or the other parts are the problem. I'm lousy at soldering, maybe that's the problem, or what?

Thanks.

 

Welcome to the Forum Krvavizmaj,

I will try to seek few clarifications that mighthelp me to offer suggestions, please!!

1. what is the schematic you have followed and whether you can try to post it for us to see.

2.Did you measure the Vpp developed - It is expected to be around 12.5 DC. If you get any less like 11V, you find inconsistancies.

3. Incidentally did you try the JDM programmer with poer supply derived from the Comport lines or externally powered.

Lousie at soldering-- you may try help from colegues konwn for good soldering for this time and you can improve in your future works.

if posting the schematic is a problem provide us with link details from where you got the diagram.

__________________
Regards,
Sarma.

 

Thanks for trying to help, this is the schematic I used
http://www.jdm.homepage.dk/newpic22.gif, and also the PCB for the schematic from the same site http://www.jdm.homepage.dk/pcb2.htm.

On the hardware test when the MCLR is enabled the voltage is 13.7V, and the voltage on the Vdd pin is always 5.3V.

The power is from the comport.

 

please see this site for further clarifications instead of typing over here

http://users.tpg.com.au/btkelly/jdm_b.htm
all the best

__________________
Regards,
Sarma.