Hi, a few weeks ago i came here trying to make a JDM programmer works on my desktop pc, i received help from some ppl (and i appreciate it), however i was unable to make the programmer works, i then tried the simple jdm and some more and i finally gave up on jdm, so now im building the p16pro40 programmer but im having some problems >.<, i first built the programmer on my breadboard, when i finished i powered it with a 20v dc power supply, i instantly noticed that both red leds turned on(i dont think theyr suposed to be on when i just pluged the programmer w/o a pic inserted), and the green(wich its suposed to be the "power on" as far as i know) also turned on but very dim compared to the red leds, my first step was to check the regulators, so i tested both regulators separately, they were both working (+5v and +8v), then i conected them as shown in the p16pro40 schematic, and checked the voltages again, i noticed that once conected like that, the output of the 7805 goes from 5v to 5.9-6.2v, and the output of the 7808 goes to around 13.8v, are those voltages suposed to be like that on the programmer?, the datashets for the 7405 gates recomend to not exced the vcc from 5.25v.
BTW, im using a C3 at 220µ F at 50v, and 78M regulators.

 

No. The output of the 78M05 is wrong and should be around +5V and the 78M08 Vo should be around +13V(all measured w.r.t. 0V) because it is reference to the +5V output of 78M05 instead of 0V.

Just build the part of circuit involving these two regulators first and verify you have got the correct voltages before moving on to other parts of the circuit.

The 7405 is not powered from the +13V. It is connected to +5V(i.e. 78M05 output).

No problem with that. The P16Pro40 had been built thousands of times and all worked.

One important reminder to all who want to build the P16Pro40 programmer. You don't have to place either a PIC into the socket or connect the programmer to a printer port until you have fully checked out that the programmer is functioning.

Using a 47 ohm resistor, one can simply ground or pull high inputs to see if the action produce an expected result in other parts of the circuit by checking with a voltmeter.

__________________
L.Chung

 

When i power up my P16PRO40 both red LED's light up, but ONLY if the programmer NOT is connected to the LPT port on the laptop, and when i connect it to the LPT both red LED's turn off and the green will turn on.

 

I just tested the regulator part aside from the circuit and got the same results, 5.9v on 7805 and 13.9v on 7808, i then disconected the 7808 common pin from 7805 output and 7805 instantly drops to 5v, this confused me, so i picked up another 7805 from my junkbox(that happens to be from the same company that the 7808 that i was currently using) and changed it from the one that i was using (from a different company) and that solved the problem! , i dont know what was bad about the other regulator(it worked fine if i tested it solo), perhaps bad compatibility . Anyway thanks for the replies, i will now continue the circuit hoping everyting will work fine.

 

As you were building on breadboard I would suggest it was probably oscillating, it's essential with 78xx regulators that the required capacitors are fitted, and as close as possible to the chip.

Changing for a different make probably changed the conditions under which it would oscillate?.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Thats a good teory, maybe the regulators were designed for different capacitors and that was causing undesired function.
Aside from that, i finally got the circuit itself to work fine, green led its on and red's are off, however when i attempted to write my 16F84A i got the same error that i used to get with JDM , "verify failed at 0x00. Programing aborted", that was disapointing , so now im trying to find out whats going on, i tried the "Read PIC" button and no red led's turned on (i saw in another thread that 1 red led its suposed to bright), i checked all inverting gates sepparately and they are working fine, i tested continuity between the cable and the circuit; everithing fine, tested led's and transistors, all fine, this is getting frustrating again, i noticed that 7805 gets warm, im not sure if this should happen as it is from the 78M series and its packed on a TO-220 case, 7808 isnt getting warm at all, im using a 120Vac to 16Vac 60Hz power supply, i really need some ideas on what could be the problem, any measures or tests i should do to find out whats wrong.

 

The usual cause is too low a voltage, or too much ripple, on the Vpp line, if you have a scope check for ripple on the Vpp pin.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

I'm not surprised. Usually the individual parts are fine, only the combination doesn't work.

Have you checked the circuit following my previous suggestions?

__________________
L.Chung

 

Hi again, i have been busy at work the last couple days, i just tested the programmer again, i checked the inverter gates 1 by 1 with the whole circuit w/o conection to the parallel port (cuz i wasnt sure if i could damage it by appling voltages to its pins), they are all working fine, i also tested the programmer using 3 x 9v batteries in series, but im still unable to get a pic programed, keep getting the same error, this is quite frustrating, i have been trying to get a programmer to work in the last month and im about to quit on this pic thing >.<, i would appreciate any extra ideas to find out the problem.

 

are you sure your LPT port is OK?

 

Download my software WinPicProg, it includes the capability to manually toggle the output lines, so you can easily measure the voltages on the PIC.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Hi again, i really dont know if my LPT port could be damaged, i dont see why it would be though, i havent used it in a while since i bought a usb printer, i never had any problems with the old printer.
I have been using WinPicProg since i started testing the programmer, using the 7406 spec, how do i manually toggle the outputs with it?, i guess probably be able to tell wheter the LPT its working or not by testing the output signals.

 

Select 'Options/Hardware', there are a row of six buttons (and one display 'button') along the bottom of the window. Press the buttons to toggle them on and off.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

And when you toggle the Output button the Input button will follow the on/off toggle If the programmer is connected and powered up

 

Hi nigel, thanx for your fast ansers before, i just played around with the toggle switches, i dont really know what is the function of each button, so i just toggled them on/off and low/high at random, it didnt make any changes on the programmer, the green leds its on all the time and the reds remain off(i supose at least 1 of them should turn on?), i measured the outputs of the LPT port on the circuit and they also obviously dont change at all, its just as if there was no communication with the computer to the programmer, is there any configuration i should do to the computer?.