Hello, I donít know if this is the problem with your unit, but some brands and/or makes of laptops do not supply enough current on the LPT port. You may want to try burring your chips on a regular desktop pc and see if that works. I had the same problem with another sst chip.
Just wondering if the Enhanced Willem Programmer supports SST39VF040 (4mb Flash-3V Vpp)?? Does the Enhanced Willem Programmer supports 3V Vpp Bios??
The Enhanced and Universal programmers don't have native support for low voltage devices. You can use an adapter that has diodes (yuk!) to reduce VCC.
The correct way to support low voltage devices is to run the programmer at the same voltage (instead of 5V) and to handle the low voltage to high voltage interface issue between the programmer and computer (some laptop chipsets have problems with low voltage signals).
The Willem 4.1 is the only programmer I'm aware of that does this correctly. All other programmers run the programmer at 5V and drop VCC to the device to around 3.6V. So they overdrive all of the signals to the device being read/programmed, and under drive the inputs to the CD4014. That is sloppy design work...
So far that design is only available from Willem (willem.org) and me (I resell his programmers in North America).