mikerm
Experienced Member
I got the expansion from AppleIIfan, and I would like to make it bi-directional to use mTCP with a parallel network adapter.
The original mod is here: http://www.brutman.com/PCjr/parallel_port.html
If anyone is feeling adventurous, I would like to see if anyone would be willing to help to see if the mod would work with the slightly different configuration.
1. The board has the 74LS174, however pin 15 is connected to another IC, SN7405N.
2. The board has a 74LS373N instead of the 74LS374, but they seem to be brothers, according to the data sheet: http://pdf1.alldatasheet.com/datasheet-pdf/view/8342/NSC/74LS373.html
3. Pin 1 on the 74LS373N is connected to pin 4 of the 74LS125AN next to it.
Would be performing the exact same mod most likely work?
Would it be likely "safe" to perform the mod, minus actually cutting pin 15 from the board to see if it works?
I would like to gather as much opinion and information as I can before making the mod (and I will do the actual bi-directional test before modding just in case), as this is the only board I have, and they aren't exactly easy to come by, on the other hand if it does go south, I'm hoping that the parallel circuit is isolated enough from the rest of it to not burn out the whole thing. I'm not new to electronics, however this is still outside of my knowledge. Any information is greatly appreciated.
The original mod is here: http://www.brutman.com/PCjr/parallel_port.html
If anyone is feeling adventurous, I would like to see if anyone would be willing to help to see if the mod would work with the slightly different configuration.
1. The board has the 74LS174, however pin 15 is connected to another IC, SN7405N.
2. The board has a 74LS373N instead of the 74LS374, but they seem to be brothers, according to the data sheet: http://pdf1.alldatasheet.com/datasheet-pdf/view/8342/NSC/74LS373.html
3. Pin 1 on the 74LS373N is connected to pin 4 of the 74LS125AN next to it.
Would be performing the exact same mod most likely work?
Would it be likely "safe" to perform the mod, minus actually cutting pin 15 from the board to see if it works?
I would like to gather as much opinion and information as I can before making the mod (and I will do the actual bi-directional test before modding just in case), as this is the only board I have, and they aren't exactly easy to come by, on the other hand if it does go south, I'm hoping that the parallel circuit is isolated enough from the rest of it to not burn out the whole thing. I'm not new to electronics, however this is still outside of my knowledge. Any information is greatly appreciated.