I have a willem 16 bit adapter I got off ebay a while ago. It works on my parallel port willem 5.0 but wont work on my gq-3x or 4x. It will fully programs a 27c322 but fails verify every time. Reads look like they are alright though.
The only difference I see from the ADP-054 and this one is a 10uf capacitor and the v3/v4 jumper which enables and disables the capacitor according to what another person said over at nesdev forums. Where does the 10uf capacitor run in between? Will someone grab their ADP-054 and check with a meter for me please.
Edit: Just got one to burn and verify after setting the speed to 0. I'd still like to try it with that cap to see if that's causing the issue using the full write speed.