---I have the same programer and I too was trying to adj v and I endedup threw my own fault burning out a few of the ics next to the db25 connector - I removed them to test and order not thinking that there were no IC numbers or paper wk that I can find to put the correct ones back - can you zoom in on your pic for me so I can read the IC numbers and put my replacement chips back in the correct places , thanksView attachment 87677 Well, after doing some more digging, it turns that the device is not so bad.
It's an improved version that should take care of all the voltage problems. I have found that there are some jumpers on the PBC for this.
In the picture, the yellow square jumpers are used for modifying the VPP. So With the trimmer I can fine-tune it, at 12.5V. And by changing the position of the jumpers, the VPP becomes 21.5 or 25V. And it stays there, there is no VPP drop. I have been able to write yesterday some old 2716 (KR573RF5 is the code) Soviet Union chips at 21.5V.
Only one I could not write, a 27128, no matter what I have tried. But I think that one is broken.
And for VCC, there is the jumper with the pink square. And I can provide three VCCs from there (5V, 5.5 and 6.2)
Moderator edit: New thread created from old thread.