Marty
Veteran Member
Hi all;
I am working on the ZFDC (Z-80 Floppy Drive Controller) Board from Andrew and John..
And on the Input to the 74LS04 pin 13 (U32) it will Automatically go to about 1.75 volts, I can Ground it with a wire and it does go to 0 volts.. Also, there are (at present no other Ic's) plugged in that are connected to that Line..
I have tried multiple different Ic's, 74LS04, 74LS14, 74AS04 and 74F04.. They all do the same thing..
Also when this Ic is out the pin goes to ground, and does not float at the higher value..
I have cleaned the Board and checked for shorts and momentarily thru a resistor pulled it to +5 volts..
With no Ic's in at all I have both pulled this pin and those next to it and those next to the pin on the other Ic's that are connected to it, Both High and Low..
No change in its behavior in spite of doing all this..
I guess, I could short this pin and those next to it to ground and +5 Via my 400 Amp Batteries, but I am NOT to Excited about doing this.. While not in the system and ALL Ic's Out of the Board.. I did this on a Wire-wrap DEC Board and I got Lots of Feedback on that..
ANY SUGGESTIONS ????????????????????
THANK YOU Marty
I am working on the ZFDC (Z-80 Floppy Drive Controller) Board from Andrew and John..
And on the Input to the 74LS04 pin 13 (U32) it will Automatically go to about 1.75 volts, I can Ground it with a wire and it does go to 0 volts.. Also, there are (at present no other Ic's) plugged in that are connected to that Line..
I have tried multiple different Ic's, 74LS04, 74LS14, 74AS04 and 74F04.. They all do the same thing..
Also when this Ic is out the pin goes to ground, and does not float at the higher value..
I have cleaned the Board and checked for shorts and momentarily thru a resistor pulled it to +5 volts..
With no Ic's in at all I have both pulled this pin and those next to it and those next to the pin on the other Ic's that are connected to it, Both High and Low..
No change in its behavior in spite of doing all this..
I guess, I could short this pin and those next to it to ground and +5 Via my 400 Amp Batteries, but I am NOT to Excited about doing this.. While not in the system and ALL Ic's Out of the Board.. I did this on a Wire-wrap DEC Board and I got Lots of Feedback on that..
ANY SUGGESTIONS ????????????????????
THANK YOU Marty
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