25023RE: [midatlanticretro] FD 1771 - Floppy Drive Controller TAX?
- Apr 3, 2012Some things I would check:
Make sure FD1771 pin 25 is truly grounded. It is
socketed, right? Did you reseat the 1771?
Likewise, make sure you have a good clock signal on
1771 pin 24.
What does the 74ls175 (u33) look like? Is it socketed
or soldered? Are its pins tarnished? Does the clock
on pin 4 of the 175 look good?
Basically, if any of the chips on the board are TI,
socketed and have pins tarnished to black or almost
black, it would probably be a good idea to gently lift
and reseat them.
Are the gate voltages on the 74ls08 (u36) good? If they
are marginal, you might be getting noise in the signal.
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