Seattle Computer Products : RAM+ Memory Card : SCP-130C

I have in my collection a RAM+ Memory Card made by Seattle Computer Products. Seattle Computer Products was a company known for making early home computer systems based on the Intel 8086 processor. However, the company also released a number of peripherals for the IBM PC. The manual is difficult (if not impossible) to find online…until now!

SCP-130 RAM+ for the IBM Personal Computer

Download link for the manual: SCP-130 RAM+ for the IBM Personal Computer

The first owner of this card must have purchased it when it was first made available, because the top of the manual says PRELIMINARY INSTRUCTION MANUAL.

This card is “Available with 64k, 128k, 192k, or 256k of memory” and was installed in an original IBM PC 16-64k.

Installation notes:

• You MUST have the entire complement of 64K bytes of memory installed on the System Board before you can add RAM+.
• Set the DIP switches on the motherboard and the RAM+ card correctly

Note: The manual says more than 544K is ‘off off off off’

The RAM+ has a DIP switch which must be set according to how much memory you have BEFORE the RAM+ is installed. Use the table below to set positions 5 through 8 of the DIP switch. Note that these positions are marked on the RAM+ board just above the switch with the designations “A19”, “A18”, etc. These designations are also used in the table:

If you already have an IBM Asynchronous Communications Adaptor, another RAM+, or an equivalent serial communications card from another manufacturer, you will want to configure this RAM+ as COM2 rather than COMl. There are two blue jumpers on the RAM+ board that must be changed to do this. One is a little to the left of the DIP switch, labeled PORT below it. Pull off the jumper, which will be covering the middle and right pins of a three-pin strip, and replace it so it goes over the middle and left pins of the strip. The board is marked with “COM1” and “COM2” so you'1l know if the jumper is toward the left it’s set for COM2 and if it toward the right it’s set for COM1.

A second change is necessary to complete the configuration as COM2. Find a blue jumper near the bottom of bottom of the board, just above the gold-plated connector fingers, labeled IRQ. This jumper will be covering the middle and right pins of a three-pin strip, and should be moved over so it covers the middle and left pins. Note that both the PORT and IRQ jumpers must always be on the same side of their respective three-pin strips: on the right for COM1, and on the left for COM2.

Three jumpers allow the serial port to be configured as COM], as COM2, or to be disabled completely. To select configuration as COM1, the PORT and IRQ jumpers must both be toward the right, set to “COM”. To select COM2, move the jumpers toward the left, set to “COM2”. For the serial port to operate the SERIAL PORT jumper must be in the “ON” position; to disable the serial port put this jumper in the “OFF” position.

The RAM+ is capable of being configured for 0, 64K, 128K, 192K, or 256K bytes of memory. Each of these amounts corresponds to 0, 1, 2, 3, or 4 columns of nine memory chips installed, repectively. If you add more memory chips to a board with less than 256K, positions 1, 2, and 3 of the RAM+ DIP switch will have to be changed. Note that these positions are marked on the RAM+ board just above the switch with the designations “S1”, “SO”, and “E”. These designations are also used in the following table:

“Parity” is a means by which it is possible to detect that an error has occurred while reading previously stored data. Normally when a parity error occurs, it is immediately reported to the computer which will take some action. The normal action for the IBM Personal Computer is to print “Parity Check” on the screen and halt. This mode of operation is selected by placing the PARITY ERROR REPORT jumper in the “ON” position (report errors).~

It is also possible for the RAM+ to suppress the reporting of parity errors to the computer. This is done by placing the PARITY ERROR REPORT jumper in the “OFF” position. This may be necessary if a parity error occurs consistently and a memory test is going to be used to locate the offending memory chip. There are four red lights on the RAM+ board, each of which corresponds to one column of memory chips (the left light to the left column, etc.).

Whenever a parity error occurs, the light corresponding to the column which had the error will light up and stay lit, which can be a great aid in locating the source of the error. The action of the lights is completely independent of the setting of the PARITY ERROR REPORT jumper.

SCP-130 RAM+ for the IBM Personal Computer

Download link for the manual: SCP-130 RAM+ for the IBM Personal Computer