Hello all and thanks for the suggestions... Here's the story so far: 1) Power appears good -- measured correct voltages at power supply header on motherboard, and at various chips on the motherboard. All seem to be within specs 2) "Power good" line stays at +5VDC -- I believe this is correct, and signals that power is indeed good 3) Processor reset line -- at power up, briefly goes to +5VDC, then back to 0VDC and stays at 0VDC -- I don't think it is active low, so this should be correct, right?? 4) Triple-checked configuration switches, and they are correct for the configuration 5) Clock input to 8088 is dead-on 4.77xxxxxx MHz (my scope shows all the digits, but I don't remember them :-) -- I think the 4.77MHz is close enough). 6) One thing that seems odd is that the ADxx (Address/Data) lines seem "stuck". The scope does not show a waveform, and measuring with a meter shows some lines right at +5VDC, some at about +4VDC and some at 0VDC. Perhaps the processor is indeed HALTed??? That's where I am right now ... I'll remeasure the ADxx lines, and post the full list of values .... Thanks again for all the suggestions!!! Rich B.