Willem programer flashing problem solved!!!

[gtsamour]

I finally came up with the solution to a problem that i recently begun having with my v4.5 willem programer.

Do you have problems with yours too? Like the programer refuses to program chips that you know for a fact that it could in the past?
Worked fine yesterday but today it refuses to program?
You do everything right (vpp 12.5V, vcc 6.2V, appropriate PSU, right dip switches for the chip you want to program, right software for your pcb version etc) but still the programer doesn't do its job? (like it gives an error on the first address or stops in the middle of programming).

Well these were the problems I had and i located the problem afterall. I suspect its the same problem with most of the people reporting similar issues... this forum is full of reports like this with the willem.

And the problem was the chip selection DIP switches guys. As much as it could sound strange, three of them were unable to close the circuit at the "on" position on my willem which was hardly used.
Do a simple test on your programmer that has problems. Turn all DIP switches at the "on" position an do a continuity test with your polymeter at the back of your board (the switches should let the current pass). After that do the same but with switches at the "off" position (no current should be able to pass). Im pretty sure you'll come up with interresting results most of you...

Willem is a good programmer but the dip switches on most of them seem to give out pretty soon. Im thinking of replacing mine with jumpers, they are more reliable.

The problem i was having was that it couldnt program ST brand 27c128 eproms (stopped right away) that i knew it did in the past (hadnt used it for 3 years now) and with 27c256 that also could program in the past but now it stopped in the middle of programing giving an error.

No need to say that after i fixed the DIP switches (replaced them) all problems went away and its working again as it should.

Hope that helps a lot of people.