apple Lisa2. One working!! - one to go?

Ok, an examination of the comments in the ROM H listing suggests that the Lisa 2/10 does look to see if the hard drive is connected and if not, then boots from the floppy drive. As the machine still gives an error number 57 on the I/O board when the widget is unplugged but the floppy drive plugged in, I deduce the fault is definitely is on the main I/O board somewhere. With the widget unplugged then I took some readings on the floppy drive card edge and compared those to the same on the working Lisa. There were some differences. Compared to the working machine.. PH0 does not show a brief 5V pulse on start up PH1 and PH2 remain at zero rather than pulsing briefly to 3.5 v or so every 4-5 seconds HDS is static at zero rather than at 4.5v and dropping to zero every 4-5 seconds DEN (ENBL) is 5v rather than zero WRD is 5v rather than zero PWM is 0 rather than 4v The WRD and the PH lines come off the IWM chip (Integrated WOZ machine). I found a few docs on this chip but I'll need to study them a little harder to try to understand how they work. Checking out the IMW chip, a clock signal is there and nothing on the input side is obviously amiss but then I would not recognise it if it was. The data and address lines are a combination of exotic looking waves. The same can be said of the data and address lines in the 6504a disk controller chip itself although A8 (pin 13) seemed to be a steady 3.8V rather than a wave. I checked quite a few of the other 71xxxx chips. They appear to be doing what they should on the straight signal. With a wave, it's hard to tell. I'm wondering if it is the IMW IC. Does this seem a strong suspect? I don't have a replacement for this unfortunately, but they are also in the Apple IIGS apparently, so not that uncommon. Terry