JDM hardware help

Thread Starter

chrischristian

Joined Feb 22, 2008
43
Hi!
I have made a JDM programmer and now trying to test it according to:
http://reprap.org/bin/view/Main/StripboardJDM#Testing

The circuit seems to be O.K. on first test ( it shows 4.20V) but, then I tick the enable data out the data in does'n get ticked and I get 0.01V between pin 5 and 13, don't know what to do. Please help I have spend money on this and 16F628 and will be my first MCU so, this has to work!!

The JDM schematic I used is attached, the clock LED blink when I turn on my PC.
 

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dclermont

Joined Mar 13, 2007
6
I'm not an expert but you are using "power stealing" from the RS232 port, you are using it to drive LED's! -- try disconnect the LED's first to see if it works.
 

beenthere

Joined Apr 20, 2004
15,819
Be nice is that big untested design disclaimer wasn't at the top of the page.

Pin 5 & 13 of what? The PIC or the serial port?
 

dclermont

Joined Mar 13, 2007
6
Be nice is that big untested design disclaimer wasn't at the top of the page.

Pin 5 & 13 of what? The PIC or the serial port?
Looking at CHRICRISTIAN post, he is changing the original JDM to add bell and whistle like LED as depicted in his thumbnail attachment as I stated if he try to drive LED from this, there will not be enough energy to keep the LED and the rest of the circuit power together.
 

Thread Starter

chrischristian

Joined Feb 22, 2008
43
Removing LEDs didn't solve the problem in fact the 4.20 V I was getiing between pin 5 and 14 is now 5.20V, I think the problem was not LEDs, I have used BC 558 insted of BC550C but I don't think that can cause trouble or can it? Should the DATA IN get ticked when I tick DATA OUT, even when MCU is not in the socket? I also found that when I measure voltage between pin 5 and pin 4 it shows 4.45 volts and when I tick ENABLE MCLR in ic prog hardware check wizard it swings to 0.02V while it should be 12V as per http://reprap.org/bin/view/Main/StripboardJDM#Testing. Please any one have ever made tis JDM programmer, help me!!!!
IN ALL ABOVE TEST IC SOCKET IS EMPTY!
 
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