Printer And Joystick Port Tests - Atari 520STE Field Service Manual

F8 DMA Count Error. Replace the Memory Controller, if that does not fix it,
replace the DMA Controller.
F9 CRC Error. The diskette or disk drive may be bad, else replace the 1772.
FA Record Not Found. The 1772 could not read a sector header. May be a bad
diskette, drive or 1772. If the test fails drive A but not drive B, the 1772 is not
at fault (likewise fails B but not A).
FB Lost Data. Data was transferred to the 1772 faster than the 1772 could
transfer data to the DMA Controller. If DMA Port passes the test, the 1772 is
probably bad. The DMA Controller could also be at fault.
FC Side Select Error – Single Sided Drive. The test tried to write both sides of the
diskette, but writing side 1 caused side 0 to be overwritten.
FD Drive Not Ready. The forma/lwrite/read operation timed–out. Probably a bad
disk drive. Verify by checking another drive. Could also be a faulty 1772.

3.17 PRINTER AND JOYSTICK PORT TESTS

The ST Port Test Fixture and STE Game Port Test Fixture must be properly
connected for this test.
The port test fixture is used to test the parallel printer port. DMA, and joystick ports.
The parallel port test writes to a latch on the test fixture and reads back data. The
joystick port tests output data on the parallel port, which is directed through the test
fixture to the joystick ports. The keyboard reads the joystick data in response to
commands from the CPU. The cables connecting the joystick ports to the test fixture
must not be reversed, or the printer and joystick tests will fail.
The game controller port test simulates joystick direction input, fire button input,
paddle controller input, and light gun inputs. The STE game port test fixture used the
joystick outputs and control lines from the STE Port Test Fixture to generate the
signals input to the STE.
3.17.1 Printer/Joystick Error Codes
P0 Printer Port Error. Data read from the printer port was not what was written.
Verify that the data lines on the PSG chip (pins 6–13) are toggling when the
test is run. If not, run the RS232 test. If the RI–DTR and DCD–DTR errors
occur, the chip is probably not being selected. Check if the chip selects are
being activated and the 2 MHz clock is present. If the PSG is selected and not
outputting signals, replace it. If the data lines toggle, verify continuity. Also
verify that J11 (Joystick 0) pin 3 is pulled up. Verify the test fixture is good by
testing another computer. If it is OK, replace the PSG
P1 Busy Input Error. The input to the MFP is not being read, or the STROBE
output from the PSG is not functioning, or Joystick 0 pin 3 is not connected. If
the P0 error also occurs, see handling for that. Otherwise, look for a signal
arriving at MFP pin 22 from J5 pin 11. If no signal at J5, the test fixture may be
bad. Verify with another computer.
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