[SunRescue] OT: RS/6000s

[James Lockwood]

On Tue, 4 Apr 2000 emp7 at cornell.edu wrote:

> This is a little off-topic, but I'm sure that someone knows absolutely 
> everything about this little problem I'm having.

I can't claim to be an RS/6000 h/w guru, but I've had to deal with a
number of them over the years.

> A friend of mine acquired a pair of old RS/6000s (one 250 and one 410 (I 
> think)).  Unfortunately they came with no keyboards, no monitors, and no 
> RAM.  I searched the net and the references I found said that some 
> RS/6000s used PS/2 RAM.  How is this different from normal 72 pin RAM?  
> Where's a good place to find some?  Do the two guys that we have require 
> PS/2 RAM or can I use standard 72 pin RAM?

Keyboards and mice are no problem with these, "standard" PS/2 units should
work fine.  Some earlier RS/6000's required Logitech mice to function
properly but the PowerPC units should have no such limitations.  You may
have problems using an off-brand PS/2 keyboard in service mode, just use a
serial console when you have to. 

RAM for the 250 and 410 is PS/2 style parity RAM, 70ns, in banks of 4.
4MB, 8MB and 16MB SIMMs are supported.  You can still download the h/w
configuration guide for the 410 from IBM, in the 250 make sure to populate
the SIMM slots under the graphics card first.

You're lucky that they use PS/2 RAM.  Many other models use very specific
IBM RAM that can cost 2-3x as much.

> And how do I see what's going on when I boot 'em up?  I tried running a 
> serial cable out the back, but was unable to see anything on my 
> terminal.  And hooking up a sun monitor to the 13w3 connector in the back 
> didn't net a video signal.

You'll need RAM in the boxes to see anything at all.  Once you've got RAM,
turn the keyswitch to Service and connect a serial null modem cable _with
full handshaking_ to the first serial port and to your terminal.
RS/6000's get very cranky with 3-wire serial cables.  Power on and wait a
while, you can see the progress of the IPL on the front-panel LED display.
A table to let you interpret these codes is on the IBM site.  Be patient
and don't get alarmed if it takes a while.

Typical framebuffers of the period output sync on green as well as
composite sync, if the video output is in range on what the monitor can
deal with it should work.

-James