IBM 5170 - Motherboard Switch and Jumper Settings

In the move from the 5160 to the 5170, IBM moved the vast majority of motherboard configuration into what IBM refers to as SETUP
Remaining is one configuration switch and one configuration jumper.

Switch SW1

This switch is used for selecting the video card type (MDA, CGA, EGA).

Card/s Fitted	Required SW1 Setting	Comment
MDA only	Rear position	If in the wrong position, "501-CRT Error" will be seen on screen at power-on.
CGA only	Front position	If in the wrong position, "401-CRT Error" will be seen on screen at power-on.
EGA only	Either position
MDA + CGA	Rear: MDA is to be the primary of the two Front: CGA is to be the primary of the two	Info source: Page 3-26 of IBM document here

    The switch is located adjacent
    to the power connectors.

    Pictured in the rear position (towards rear of computer).

Jumper J18

This jumper controls whether the 5170 motherboard decodes 512 KB of RAM, or 256 KB of RAM.

'512 KB' is the normal setting.

The only reason for changing the jumper to the alternate position is when all of the following is true:
* You have a type 1 motherboard (has piggybacked RAM chips); and
* That motherboard has only RAM bank 0 populated - provides RAM from 0 to 256 KB address range; and
* You are going to provide the additional 256 KB (addresses 256 to 512 KB) via a RAM card (instead of using motherboard bank 1).

    The jumper is located at the front of the
    motherboard.

    Pictured in the '512 KB' position.