>Before writing your own diagnostic programs, why not >give it a try on some other PC?



Ijaz and others,

This is to report that I tested it on a desktop.

I first changed the configuration of the parallel port hardware
in the desktops CMOS, changing it to SPP from ECP+EPP.

I then ran the software and results were the same. Verify error
on first byte. Actual byte value was 02 while the hardware
returned FF.

The second mod that was tried is as follows:

1. A buffer based upon 2 NPN small signal transistors was added
between pins 9 of both DB25 connectors. This buffers D7 which
feeds ICs U3 U4 and U5.

2. Similarly another buffer based upon 2 NPN small signal
transistor was added between pins 3 of both DB25 connectors.
This buffers D1 which feeds all the ICs except U1. (Probably
the clock).

However no change in the result.

Any ideas.

Aurangzeb