here is what we have up to 6-21-2011
Look at the sticker on the back of your console to get some clues:

1) Date

July and earlier 9504
Before august 5th 9504, maybe 0225
After this 0225, maybe 9504
after august 10th 0225, maybe Hitachi

2) LOT Number

11XXX 0225
104XX 0225, maybe 9504
103XX 9504, maybe 0225
102XX 9504
101XX 9504
104X 9504

3) Serial Number

9th number

2 9504, maybe 0225
3 0225, maybe 9504
4 or 0 0225, maybe hitachi


If you wondering why this information is important its because the 9504 can be modded easily. The 0225 chip is write protected and CANNOT be modded. It can however be dumped into a computer and then a PROFESSIONAL solderer (gotta know one of those!) can put in a new chip or you can also purchase a new drive controller board and then reprogram it with the info you got from the old one