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are properly inserted into the IC sockets.
Check that there
are no pins outside the sockets and that there are no pins
bent under the IC's.
P9.
Configure the RAM board with all the address switches OFF.
Install the RAM board in the computer and then turn on the
power and depress and release the reset switch.
The LED
should NOTNbe lit.
If it is, turn off the computer and
locate the problem before proceeding.
P10. Select an unused address region in your computer and
configure the address switches on the RAM board for that
region.
Plug the board in and turn on the computer power.
Do not execute any software which initializes the RAM board.
[E.g., the HORIZON DOS will initialize all RAM in the
computer.
To bypass this, boot up with only 8K of the board
(addressed at 2000H) turned ON, and turn on the other 8K
after boot load.] Next, examine cells in the address region
of the memory board using a monitor program or control
panel.
Eventually, you will examine a cell which powereo up
with a parity error.
When this occurs, the LED should
light.
Now turn off the computer power.
If the LED did not
light, then locate and correct the problem before
continuing.
Pll. Power up the computer with the RAM-16-A board installed in
the motherboard.
Use a program such as the standard HORIZON
DOS initialization to store into each byte on the board, to
clear all incorrect parity bytes.
Again, enable the parity
detection by executing the two instructions shown in the
previous step.
(It is normal for the LED to turn on
momentarily during this sequence:
it should turn off when
the arming instruction is executed.)
It should not now be
possible to turn on the LED by examining cells on the RAM
board.
If .the LED does turn on, then either the memory is
making errors or there is a problem with the parity option.
Locate and correct the problem before continuing.
The parity option is now assembled and checked out.
21
North Star 16K RAM BOARD
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