Lost on the switchless Saturn mod...

[Peyn]

So I figured I would get rid of that big jumble of cables and that big ol region switch sticking outta the back of my saturn the other day, and I decided on the switchless import mod on the main site. I thought I knew what was going on inside the system, but I guess I really have no idea, because today when I tested my mod, I could get the system to play US games but not imports. Strangely, I could get US games to work only after hitting the reset button, which I have mapped to the "select" pin on my 74157 IC. Another thing I noticed was that  when I first start up my system, every single pin on the 74157 reads +5V. What does this mean??

UPDATE: I just tested the mod after pressing the reset button, and it looks like every pin reads +5V even after resetting! To me my solder work looks just fine, there is no cross contamination or shorts that I can identify, but I suppose the possibility remains. The plot thickens...

[Lawrence]

All the pins from the saturn chip will read 5V until they're connected to ground. If you've connected GND to one of the A/B pins on the '157, you should be getting GND on the corresponding Y pin when the 157 is switched the right way.

Keep in mind that the chip only needs to do its job during powerup, once the system's booted, it doesn't check again, so the ongoing status of the jumpers is not important.  So, basically, you have to test the pins WHILE holding the select switch...  Still, some of them should be GND all of the time, so...

Make sure you've really got GND on one of the A/B inputs?

[Peyn]

aha! Found a questionable connection on the bottom side of the motherboard, not only on the GND wire but also on +5V. Will report back!

UPDATE: Thanks Lawrence, you called it. The loose connections were fixed, and now I have a fully functioning switchless region mod. I owe you one, big time.