Johan,I built the JDM programmer from the drawing on this page:http://www.jdm.homepage.dk/newpics.htmI substituted a 2N3904 for the BC547B.28 pin socket connections for 16C745 as follows:RB7 - pin 28RB6 - pin 27MCLR - 1Vss - 8 and 19Vdd - 20These are the same as you list with the addition of a second Vss connection on pin 8.I successfully programmed a PIC16C745 with it. The programming software (IC-Prog 1.05C) verified the PIC contents. I built the programmer with an 18 pin socket as well. I use it to program 16F628's as well.This is a neat little programmer, but it depends on the bipolar voltage swing of the RS232C serial port to generate the programming voltage. There are no guarantees a given PC serial port will have adequate voltage levels. You will most likely be okay, but if you want to be very conservative, you might add a smaller socket and try the programmer on a less expensive, flash PIC like the 16F628. Mikewww.mikesflightdeck.com

Hi Jordan,The 10K resistors are used for pull-up purposes and are required by the PIC on those specific pins.Mike made a very good point that you should use an inexpensive flash PIC to test your programmer and software settings before attempting to program the OTP 745.If you are using IC-Prog, I found that a delay of 9 or more (default is 4) in addition to "verify during programming" reduces the failure rate of programmed PICs but this is all highly system dependant and you'll need to experiment a little to find the best settings for your setup.I also suggest leaving the room when the OTP PIC is being programmed since most PC

I'm sorry Johan, I got your name wrong...seems I need glasses!-Leo

Leo and MikeThank you for the quick response and valuable advice.Being new to PIC programming, I will now for sure try the 16F628 first to see if all goes well.RegardsJohan