Dreddnott,
If you had a 5160 or a 5170, then I could have provided a replacement BIOS chip. Not the exact IBM part, but a clone.
Replacing a BIOS chip in a 5150 is a different story.
For those who will comprehend:
If a BIOS chip in a 5160 (U18/U19) or 5170 (U27/U47) fails, I can easily supply a replacement. I simply burn a commonly obtained 27256 EPROM. I have copies of those BIOS chips (as files) and I have spare 27256's. Obviously the replacement needs to be done as a matching set, and some BIOS' are motherboard specific (eg. 16/64K versus 64/256K).
Unfortunately, in the 5150, the BIOS chips are not so easy to replace. IBM used a PROM chip that nowadays is expensive to purchase. The AM9264DPC (or equivalent) only seems to be stocked by specialist IC supply companies that deal with orders worth $500 or more. Even if I obtained some, finding (or making) something to burn them is the second hurdle. Doable but a lot of expense/effort, particularly when you consider that periodically, 5150 motherboards can be obtained on eBay for around the $10 mark (plus shipping).
I can't find a pin-for-pin EPROM equivalent for the AM9264DPC.
A 'messy' EPROM based solution is on the Internet at:
http://groups.google.com/group/comp.../a2a940c74751409e?hl=la&lr=&ie=UTF-8&oe=UTF-8
In that solution, a modified 2764 EPROM (after being burned) is used. The result will look bad. Not only will the chip have wires running over/around it, but a 28 pin chip is being fitted into a 24 pin socket (i.e. overhang on both ends).
Creating a binary file from a 5150 BIOS chip
--------------------------------------------
In this example, a binary file named F600_U29.BIN is created that contains the contents of U29 (8K block at F600:0)
C:\>DEBUG
-NF600_U29.BIN
-RCX
CX 0000
:2000
-MF600:0 2000 0100
-W0100
Writing 2000 bytes
-Q