I'm working on getting a system 80 going and I found this chip on the control board A1. I don't think I need a logic probe to tell me that it's bad. But I need some help finding a replacement. I don't understand the numbers on these. I checked Great Plains and they list them under the main number like this one - 7404 but they are out of stock. I have a 7404 that I purchased when I fixed some acid damage on this board and I'm wondering if that will work as a replacement (pictured below)?

Thanks guys,

ic.jpg 7404.jpg

Awesome. Thanks!