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BOARD CHECKOUT
-
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The following checkout ·Iprocedure should be followed for a newly
assembled board.
It can also be used to diagnose problems in
previously operational boards.
- This checkout procedure l assumes that no other board besides the
ZPB is plugged into the S-100 bus.
This makes it possible to get
the ZPB operational eveh if no other board in the system is yet
working.
This procedure assumes only that the correct
unregulated voltages have been applied to the bus,that the
computer has a reset switch, and that the bus lines are not
shorted to each other.
I,
The following terms arelused in specifying expected test results.
1
GND
LOW
HIGH
+5V
AC
ground, 0 volts DC
logic zero, 0-.7 volts, normally about
.3
volts
logic
on~,
2.4-5.0 volts, normally about
3
volts
+5 voltslfrom power supply
Signal
w~th
pulses (as opposed to DC signal)
15
When referring to the
n~me
of a signal from the schematic
drawings, if the signal lis identified with a bar over its name
then the name of the signal is followed by a slash (E!.g., STORE/)
in the checkout instructions.
When describing an AC pulse, the
notation (±W,P) refers tio a positive or negative pulse with a
width of Wand a per iod lof P.
For example, a posi tiv'e pulse of
width 125 nanoseconds
a~pearing
every 25 microseconds would be
represented as
(+125n~,25us).
See Appendix 1 for details on how
to detect pUlse signals.1
-The abbreviation MB befol1re a pin number indicates a bus pin on
the motherboard.
,
I
'
If an oscilloscope will
~e
used to test tHe board, a "scope
ground" may be installedl by soldering a "bridge" of jumper wire
between the two PC board
l
holes that connect edge connector pins
50 and 100 near location 2A.
Note that either of the two
regulator machine screwslcan also be used for ground test points.
Cl.
Check for correct clock signals on the ZPB as follows:
,
A. Install a jumper wire at PE (near location 4G) if the PE
trace was has been cut.
B. Remove the lW jumpei (near location 6G) if it was previously
installed.
I
North Sttar Z80A PROCESSOR BOARD
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