North Star RAM-16-A Manual page 20

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for refresh. Occasionally two more during stores.
Note 2: Signal is complicated, with many transitions per
loop.
Note 3: Rises during one SMI pulse, falls during the
next, alternately. Additionally, for those stores that
actually reference the chip (1/16 of the stores), the
signal goes LOW during the first store and HIqH during
the second.
Note 4: Four pulses per loop, two fetches and two stores.
H. Check the fQllowing data output signals on the RAM-16-A. If
you are using an oscilloscope, then trigger on ID pin 11 or
the upper end of R10 at 12E (SMl) on the RAM-16-A.
Signal Locat:iQn Description
MD5
10.A pin 14 AC, see note 3 above
MD4 IIA pin 14 AC, see note 3 .above
MD6
12A pin 14 see note 5 below
MD1 13A pin 14 AC, see note 3 above
MD0 14A pin 14 see not 5 below
MD2 15A pin 14 see note 5 below
MD3 16A pin 14 AC, see note 3 above
'MD7
17A pin 14 see note 5 below
Note 5: Mostly low, high during store cycles outside of
the address range of the board.
I. Replace the 74LS373 at location 17E, replace the 74LS280 at
location 10E if it was removed, remove the jumper wire, and
re-enable the processor board PROM option if it was
disabled. .
North Star 16K RAM BOARD