Atari 1040STE, Руководство по обслуживанию на месте

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3.2 TEST CONFIGURATION
With the power switch off, install the Diagnostic Cartridge with the label facing UP.
Important: if the cartridge does not have the plastic enclosure; BE SURE THE
CARTRIDGE IS INSTALLED WITH THE CHIPS FACING DOWN.
Connect cables from STE test fixture into the hard disk port, parallel port, and joystick/
mouse ports. The joystick cables should be plugged in so that, if the fixture ports were
directly facing the computer ports, the cables would not be crossed. Plug the RS232 and
MIDI loopback connectors into their ports. Plug the color monitor into the monitor output (a
monochrome monitor can be used instead).
Make sure the switch on the STE test fixture is in the position marked INT, otherwise the
program will not proceed past the initialization.
Power on the unit. Some tests will be run automatically, in a few seconds the menu screen
should appear. If the screen appears, skip down to
section 3_4: ST Diagnostic Cartridge,
below. If not read the next Section 3.3: Troubleshooting a Dead Unit.
If the unit is being used as a terminal for a host computer, it should be disconnected from the
host before using the diagnostic; otherwise, the host may think someone is logged on. and
will send messages which will act like keystrokes input to the diagnostic.
3.3 TROUBLESHOOTING A DEAD UNIT
In the event that the system is correctly configured and powered and no display appears,
this is the procedure to use for determining the problem. This assumes elementary steps
have been taken, such as checking the LED in the forward left corner of the computer to
verify the unit is powered and making sure the monitor is working.
1. Connect a terminal to the RS232 port of the unit under test (U.U.T.). you can use an
STE running the VT52 terminal emulator program – see the owner's manual for
setting up the VT52. The cable should connect pin 2 (serial out) of the U.U.T. to pin 3
(serial in) of the terminal and vice versa. Connect pin 7 (ground) to pin 7. The
terminal should be set up for 9600 bps, 8 bits of data, 1 stop bit, no parity (this is the
default condition for the VT52 emulator).
Insert the Diagnostic Cartridge into the U.U.T., and power on the unit. If the
Diagnostic Cartridge messages appear on the display of the terminal, use the
diagnostic to troubleshoot the computer. If not, the computer will have to be
disassembled to troubleshoot. Refer to section
3.4. STE Diagnostic Cartridge for
information on using the cartridge.
If no activity is seen on the RS232 port or display, continue with (2) below.
2. Disassemble the computer so that the printed circuit board is exposed (see section
4. Disassembly ). Power up the computer. Using an oscilloscope, verify the 8 MHz
clock to the 68000 CPU. Replace the oscillator if necessary. Then check the HALT
pin of the 68000 CPU. It should be TTL high. If so, go on to 3 below. If not, the CPU
is halted. The reasons may be: (a) bad reset circuit. (b) double bus error. (c) bad
CPU.
Check (a) by observing signal on input of the two inverters on the HALT line. Check
(b) by observing BERR of the CPU as the unit is powered on. It should be high
always. If there are logic low pulses, some component is malfunctioning and
GSTMCU is generating the error. Verify the clocks to GTMCU, tracing back to the
Shifter and MC (master clock) if necessary.