> -----Original Message----- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Noel > Chiappa via cctalk > Sent: 19 August 2017 23:26 > To: cctalk@classiccmp.org > Cc: j...@mercury.lcs.mit.edu > Subject: Re: DECstation 220. Another Impasse > > > From: Rob Jarratt > > > I have just written a new blog post > > > the comparators are not producing valid output, the input signals are > > varying abave and below the reference voltage, but the outputs never > change. > > Don't forget that when the output of chip A is wrong, that might be caused by > chip B which it is driving... ('All digital circuits are made out of analog > components', and all that...) >
Good reminder, thanks! I will add some chip Bs to the order as well as a precaution (74LS244D although I can only find DW, hopefully no difference). Regards Rob
