AMX TXC16 Plus Specifications download pdf (Page 200)

SG-2000 MANUAL 193

The SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA

23.4.3 Pretest

Visual inspection. Look for any mechanical defects.

Check for solder bridges, wrong parts installed, and shorts by comparing to the

sample head processor board. Check all five jumpers.

Use the multimeter in the Ohms position. Check for short circuits on the 5VG,

5VSW and 13.6VSW lines. Note: the 5VG and 5VSW lines are connected

together by jumper JMP5.

23.4.4 MicroProcessor Ports Test

Connect SGC Processor Ports Test Board to 13.6 V power supply.

Connect the ribbon connector on board test board to J1 on the head processor

board under test.

Install the SGC 6805 Processor Ports Test Chip in the IC16 socket on the CPU.

Install the MicroProcessor chip in IC9 and all other socketed ICs.

Turn on Ports Test power switch. The following should be checked.

The Port A LEDs should strobe from A0, A1, …, to A6 then A7.

The Port B LEDs should strobe from B7, B6, …, to B3 then B2. Note: LEDs

B0 and B1 should not light up.

The TPR LED should also be on.

Press the TPR button. The TPR LED should go out while the button is

pushed and turn back on when released.

The Data LED should be lit.

If the board fails one of these checks, turn off the Ports Test Board. Uninstall the

socketed ICs one by one in this order: IC19, IC18, IC7, IC11, and IC8 to find the

problem area. Use the digital logic probe in the TTL position to trouble shoot

the board.

Repeat MicroProcessor Ports Test after every IC removal.

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AMX TXC16 Plus Specifications Page 200