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Building a ZAltair Z80c Computer #2
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SolidWorks Designed Oak Cabinets
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Building the ZAltair Z80c Computer
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15A 250V Rocker Switch On/Off Power Socket

RED wire = LINE IN . . . . . BLUE wire = NEUTRAL IN . . . . . YELLOW wire = GND
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The Mean-Well Power Supplies

You need ONE: "RT-65C" for +15V and -15V
Digikey.com or Mouser.com or JameCo.com

and ONE: "HRP-75-7.5" for +8V
Digikey.com or Mouser.com or JameCo.com



DigiKey.com is one source for the power connectors

WM2104-ND 0009503061 Molex CONN RCPT HSG 6POS 3.96MM

WM2300CT-ND 0008500105 Molex CONN 18-24AWG CRIMP TIN

WM4624-ND 0026604060 Molex CONN HEADER VERT 6POS 3.96MM



Do you have the recommended boards & Power Supplies etc.
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9-Slot Backplane
No components needed other than the S-100 Edge Connectors a jumping the fuse points


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Search criteria
"100 pin 2x50 S100 Bus Backplane Pitch Card Edge Connetors"
or
"card edge connector dual 100"

EADC 346-100-520-202
or
EADC 346-100-500-204
or
EADC 346-100-520-802 or FUPH8010-100MTNE

DigiKey.com or Mouser.com



The Mean-Well Power Supplies

You need TWO: "RS-25-15" for +15V and -15V
Digikey.com or Mouser.com or JameCo.com

and ONE: "HRP-75-7.5" for +8V
Digikey.com or Mouser.com or JameCo.com






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ZAltair Z80c Basic Boards



Don Caprio mini-Front Panel board



Cromemco ZPU CPU board



Mike Douglas/FarmTek FlexRAM board

The ROM is Enabled to allow for the AltMon Monitor to be active.

SW1 = 11111111 ... SW2 = 1111100 ... SW3 = 00000000 ... SW4 = 00000011

SW5 = 1111 ... SW6 = 0000 ... SW7 = 1000 ... SW8 = 11111100
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Patrick Linstruth Deltec Enterprise 88-2SIOR1 board (a Future Addition)

Addresses 14h/15h and 16h/17h
BAUD set to 9600 8N1
Port 0 Set for Control I/O ... Port 1 Set for No Flow Control

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Troubleshooting the Build
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First Steps, Check Voltages on the S-100 Bus and Boards

All Check OK
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Power ON ... STOP + RESET
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After STOP + RESET ... Just STOPPED

Cannot see address LEDs increment with DEPOSIT or EXAMINE

Another problem is some LEDs are nice and bright, while others are super DIM

Double checked the resistor networks Okay.
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Chip Tester (c) Tauntek, R Grieb Version 0.60 December 29, 2022 Slave code version is: A2
......Enter chip number to start

......> 74LS107
......Found 74LS107 in our database

......> T
......Vss pin current with only pulldowns enabled is ~0.0 mA
......Checking inputs for shorts or leakage...
......Input levels look OK with voltage dividers applied
......Checking input connections...
......Input pin 4 may have a bad connection: 0.19
......Input pin 11 may have a bad connection: 0.20
......Logic test:
......Testing thresholds: VOHmin >= 3.20, VOLmax < 0.35
......Inputs:............Clks:............Outputs:
...... 1 4 13 8 11 10 12 9........3 2 5 6

...... 1 L H L H H L I I.........L/0.10 H/3.20 L/0.10 H/3.17
...... 2 L L H L L H N N......L/0.08 H/3.19 L/0.09 H/3.17
...... 3 H L H H L H N N.....H/3.20 L/0.09 H/3.17 L/0.09
...... 4 L H H L H H N N.....L/0.09 H/3.20 L/0.09 H/3.17
...... 5 H H H H H H N N....H/3.19 L/0.10 H/3.16 L/0.10

.......Tests failed


......> T
.......Vss pin current with only pulldowns enabled is ~0.5 mA
.......Checking inputs for shorts or leakage...
.......Input levels look OK with voltage dividers applied
.......Checking input connections...
.......Input levels look OK with pulldowns applied
.......Logic test:
.......Testing thresholds: VOHmin >= 3.20, VOLmax < 0.35
.......Inputs:............Clks:.........Outputs:
....... 1 4 13 8 11 10 12 9...........3 2 5 6

....... 1 L H L H H L I I............L/0.19 H/3.27 L/0.19 H/3.26
....... 2 L L H L L H N N..........L/0.18 H/3.26 L/0.18 H/3.25
....... 3 H L H H L H N N.........H/3.27 L/0.20 H/3.27 L/0.19
....... 4 L H H L H H N N.........L/0.19 H/3.26 L/0.18 H/3.26
....... 5 H H H H H H N N.......H/3.27 L/0.20 H/3.28 L/0.20

.......Tests passed, chip looks OK

.......>
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Hand Coded Page by Walt Perko