Latest Developement with JDM

[Guest sstandfast]

Hi, I'm back and I am still having the same problem with my JDM.  Since my last posting several modifications have been made.  They are as follows:

1)  I have since rebuilt the programmer on a PCB using the board layout found on Thorsten's webpage.  I used all new components on this board save the resistors and the 8v2 zenner (the 5v1 zenner was replaced- fried during removal).  Therefore all components are in working condition.

2)  IC-Prog was upgraded from version 1.04A to 1.05A.

However, with these new developments I am still unable to program my PIC.  I still receive the error "Programming Failed at Code address 0000h".  The voltages I am reading with this new programmer that I have read are:

Vss to MCLR:  13.29V (still a little low)

Vss to Vcc:      5.06V

Vss to RB7 (pin 40):  4.66V (very low but within the .5v tolerance)

Vss to RB6 (pin 39):  still an unstable (but apparently normal) reading of a falling voltage starting from about 5v falling to around 3v.

With a chip in the socket and the read command issued I read a voltage of 13.28V across MCLR and 5.06V across Vcc.

All voltages were read with a digital multimeter and I/O Delay in IC-Prog set to "1".  (On a side note changing the I/O delay did not effect the voltages any.  I still measured 13.29v across MCLR with delay raised all the way up to 10)

Now according to Thorsten's previous posting on this topic the unstable voltage measured on the serial clock is normal and will stabilize when the chip is being programmed.  With regard to this statement, is the voltage also supposed to drop across the rest of the circuit as well when this test is administered?  The reason I ask this is because whenever I start the "Enable Clock" test in IC-Prog, the voltage drops across the entire circuit.  MCLR drops from its normal 13.29 to around 11v or so and continues to decrease.  On Vcc the voltage drops to 2.5v and continues to diminish.  The "enable clock" is the only test where a discernable voltage drop is detected, all other tests return normal. Like Thorsten said however this may be normal behavior of the JDM (as I am able to measure the correct voltages when reading a chip) and I should not worry about it but I just thought it was worth mentioning.

Also according to Thorsten's previous posting, the 13.25 V on MCLR with my previous vector board version of the JDM seemed a bit to low to him.  I am assuming that 13.29V is also somewhat low as well.  Swapping the 8v2 zenner out with an 8v7 zenner should increase this voltage shouldn’t it?  Also the 4.66V on the data pin (pin 40) seams a bit low to me as well.  With “data out” enabled the voltage on the DTR/CTS (DB9 pins 4 and 8) side of the transistor, which I believe is the collector if I remember correctly, the voltage is 5.06 just like it should be.  However on the PIC side of the transistor (pin 40) the voltage is like I said earlier 4.66V.

One other quick question before I close; does anyone know how I would set up a serial port monitoring software, like HyperTerminal, so I can monitor the traffic that IC-Prog Is producing on the RS232 port.  This might give me a chance to see which end my problem lies on, computer hardware/software or JDM hardware.  If anyone has any suggestions please let me know.  You can respond by posting a reply on this forum or you can email your reply to me at sstandfast@yahoo.com.  

Thanks,

Shawn

[Guest sstandfast]

Sory for the double posting.  I tried to reply under the orginal thread but my browser would not show the update so I started another thread instead.  However, I am now able to see the reply so this posting is on here twice now.

Shawn

[Guest sstandfast]

UPDATE!!!

I have now swapped the 8v2 zenner with a 9v1 zenner as I could not obtain an 8v7.  I am now reading voltages across the circuit as follows:

MCLR :  13.99

Vdd : 5.05

RB7 : 4.61

(I/O delay set at 10 and all voltages measured with a DIMM)

All voltages are within all acceptable tollerences but I am still unable to program/read the contents of the chip.  I cannot figure out why the programmer is not working  :(

Also I need to make an amendment to my previous posting.  The voltage measured on the collector of Q2 was not 5.06 like I said, it was 11.54 with respect to RS232 ground.  sorry about that.

Any advise you can offer would be greatly appreciated.

Thanks,

Shawn

[Guest alienspice]

Are u using Api drivers?

On my cpu the JDM programmed the first 2 times after that it wanted work... so I switched to another cpu running 98se...and it worked!

Hope this can help

Ale

[Guest sstandfast]

Guess what?  After hours of frustration and headaches, not to mention numerous posts bugging you guys, I finally figured out what was causing my troubles.  All it was was a loose solder connection on pin 8 of the DB9 connector.  The solder joint wasn't making good contact with the PCB and therefore wasn't able to send/recieve data.

Being a newcomer to electronics and electrical design I think I just learned the first, most important, and probably the most basic rule of circuit design:  "Always check your connections first before crying for help."

Thanks again for all your help.  I really appreciate all you seasoned electritions out there putting up with clumsy beginners like me.

Thanks,

Shawn

[TK.]

Being a newcomer to electronics and electrical design I think I just learned the first, most important, and probably the most basic rule of circuit design:  "Always check your connections first before crying for help."

This must be highlighted.

Well Done! :)

Best Regards, Thorsten.