Found this on AK
You're not the first one to ask for these extremely rare IC's. PA1001A is a bit easier to find, but the PA1002A.........forget it!. I heard the PA1002 will work but you'll lose the 'Muting' function. These were special IC's made by only Pioneer. Best chance is to find a junk 1080, 1280, 1980, TX-9500II, or a TX9800.
You're not the first one to ask for these extremely rare IC's. PA1001A is a bit easier to find, but the PA1002A.........forget it!. I heard the PA1002 will work but you'll lose the 'Muting' function. These were special IC's made by only Pioneer. Best chance is to find a junk 1080, 1280, 1980, TX-9500II, or a TX9800.