WARNING: If you use this info below and blow/destroy/frazzle or otherwise maim your IP17 then don't blame me - This info is not a guide to upgrading your R4000 IP17 - its just my record of the visible differences between the two boards that I have!
One day when I was filling the SIMM slots on our R4400/150MHz IP17 board, I noticed that the rev number of the board (030-0512-003) was a piece of paper stuck over an older rev number (030-0212-009 Rev B). Also there appeared to be some strange modifications to the circuitry via the use of some external blue wires. So when I got an R4000/100MHz IP17 board I decided to have a look at its rev number as well and try to record the visible differences between the boards. Sure enough, the rev number on the R4000 board (030-0258-003) is also on a piece of paper stuck over an older rev number (030-0212-007 Rev A).
Here are the visible differences in five parts - but remember the warning above. I don't know enough to attempt this upgrade myself so I certainly dont advise that you do anything either! This info is not a guide to upgrading your R4000 IP17 board - its just my record of the visible differences between the two boards that I have.
Part 1 - The 20 pin PAL just near the IP17 power connector
Power connector is just to the right, SIMM bank behind, top clip to the
There are four wires running from the chip with the white paper label (which is 070-0814-003 with 7CD0 under this number). The first three are visible in the full size image. The last one runs behind the chip to the last leg on the right. For the purposes of this discussion, we'll number the legs from front left in an anti-clockwise manner. Thus:
Part 2 - Where do the four wires go?
The four wires go along the top of the IP17 from the chip shown in part 1. This picture is oriented such that the backplane connectors are parallel with the bottom of the photo. Wire ? splits off from the rest just past the SIMM bank and heads down to a chip between the two banks shown. Wires ?,? and ? continue down to the chips shown in part 3.
Part 3 - Three wires go here
Wires ? and ? go to the same leg of the chip in the lower right of the photo. Wire ? goes to a leg of the chip shown in the upper left of the photo.
Part 4 - One wire goes here
Wire ? goes to the leg of the chip shown in the centre of the photo.
Part 5 - What the hell is this chip?
Thats almost it. Apart from the oscillator and the CPU (obviously) one other chip is different. This chip is a removeable chip and it is in a socket near location F3C4. On the R4400 board this chip is rev 070-1200-001 DB20 whilst on the R4000 board this chip is rev 070-0815-002 DA20. Anybody know what this chip is and whether it makes a difference? If so then mail me please.
Here's a picture of the chip and its surrounds just in case the location number doesnt get you there. To orient youself, this picture is taken such that the backplane connectors are parallel to the right hand side of the image with the lower rear SIMM slot visible at the left.