Steve Toner
Experienced Member
Anyone familiar with the 20261058 PCB (Korean-made 26-3127B)? I can't find a schematic for this particular board online.
I'm wondering what the purpose of R33 is. It's a 10K pullup resistor on DD0 (IC14 pins 2/14, IC3 pin 8 - IC14 is 4164 RAM and IC3 is MC6847T1/XC80652 VDG). It looks to be totally unnecessary - none of the other data lines have pullups, and I'm seeing very strange waveforms on DD0.
I'm wondering what the purpose of R33 is. It's a 10K pullup resistor on DD0 (IC14 pins 2/14, IC3 pin 8 - IC14 is 4164 RAM and IC3 is MC6847T1/XC80652 VDG). It looks to be totally unnecessary - none of the other data lines have pullups, and I'm seeing very strange waveforms on DD0.
