a modified JDM

I found this, and it should be helpful

**broken link removed**

Also on that page is a link to the RCD programmer. That programmer also works around the problem with the original JDM programmer (supplying 5V to the PIC when it is not being programmed, which does not follow the programming specs). The RCD programmer also seems to consume less power. It works most of the time with my laptop, where the JDM programmer would never work. The big disadvantage of the RCD programmer over JDM is it cannot program the OTP chips.

Dan East

I found it cannot program for larger chips. Because I test it with 877 and I didn't work.

I've only used it with the F629. Did you try using a smaller R3?

Dan East

No I didn't.

Did anyone try JDM or RCD with 877A? pls give me the detail circuits. <<< Got problems.. don't know why, trying to test with JDM, because cannot work with RCD.

May s.one check this for meeh?

I would like to program for 877A and 876A, thus I add 28socket and 40 one to JDM. If anyone did this, pls help meeh. I don't know why I cannot program for 877A.

I replace BC546 by C1815 because it's also the general transistor. The difference is only the pinout. BC546 is CBE standard, and C1815 is BCE standard. And this is not the layout, thus, no problem with it.

I'll upload the layout later.

urgent help