The 9100A Tester

 

The 9100a tester is a 1988 vintage microprocessor test device. You plug a processor-specific pod into the processor socket, and it allows you to look around inside the machine. It is not an in-circuit emulator. I don't think that it can actually run a program in the target system. But it can run scripts that allow for debugging and test of boards. My specific interest is to use it for pinball machine boards using a 6809 processor.

 

Here's the machine disassembled on my office floor. It is apart because it has three problems:

 - A failing Miniscribe HDD
 - A non-working floppy
 - A ram bus  test error at E0000 (the video card memory area, not installed in this machine).

 

 

  
Here's a picture of the logic board for a TEAC FD235GH floppy disk drive. Floppy disk drives have evolved to be $10 devices that ship with a minimal configuration. Lots of pins are disconnected, and the drive is soldered for DS1 (i.e. the "second" drive in a system) to eliminate the need for twisted floppy cables in the PC.

Our job is to restructure the drive so that it lines up with a 1988 floppy configuration.

  

 

Upgrading the EPROM

We need to do this to enable the most up-to-date SCSI driver so we can escape the clutches of Miniscribe. Not too hard. First, you need a pair of 27C512 EPROMs. I tried to buy mine from Fry's, but my local store only had one and the next closest store was out of stock. the third store had them, but I got them home only to find that they were 27C256. I found some clean new TI parts at HSC for $2.82 each. Programmed them up and inserted them. You have to cut W2, which is the second jumper down on the left hand side of U28. It is unlabeled, so you have to look at the manual.

These are the EPROM files that I used.

9100A_U46.BIN
9100A_U47.BIN