Posted By
weidi
on 2021-12-20
11:31:30
|  Re: Cartridge port Not working correctly
I have to correct myself:
U2 - CPU - R/W output is on pin 39 (not 23)
7406 is U7 (not U6 which is 7404 on my Plus/4).
Correct measurement would be:
1) U2 pin 39 - CPU R/W output
2) U2 pin 27 - CPU P3 output
3) U7 pin 3 - 7406 input (should be the same as U2 pin27)
4) U7 pin 4 - 7406 OC output (can be +6.8V when Datasette is on)
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