SPECTRUM +3 SELF DIAGNOSTIC TESTS

The Spectrum +3 test software comes on a rom board. This should be plugged into the Expansion I/O slot of the +3. The +3 should also have a loopback cable plugged into the KEYPAD and RS232 sockets, two joysticks plugged in, and monitor, TV and audio amp connected.

Turn the machine on. One of two things will happen.

  1. A test card with some text will appear. Follow the instructions on the screen.
  2. No text or testcard. In this case, note the color of the edge of the screen. It will either be a steady color or flashing regularly with a predominant color. Consult the table below to find out which RAM chip has (probably) failed.
    ColorSTEADYFLASHING
    BLACK IC 17 IC 32
    BLUE IC 18 IC 31
    RED IC 19 IC 30
    MAGENTA IC 20 IC 29
    GREEN IC 21 IC 28
    CYAN IC 22 IC 27
    YELLOW IC 23 IC 26
    WHITE IC 24 IC 25

If you follow the instructions on screen from the first occurrence, then everything should be self-explanatory, The RAM test, if it finds a fault, will give two numbers. The first is the address at which the fault was found, and the second is the bank of memory which contained the address. If the address is zero, then it is probably not a RAM fault, but a paging hardware problem. Note that there is no way to fail the keyboard test - if a key won't respond then you can progress no further.

The cassette test comes in two parts. The first cassette test is similar to the ULA sound test, and is the last test in the ROM program. The tone it asks you to hear is much quieter than the other noises. The second cassette test comes on a tape and is used when the BASIC is running. Turn on the Spectrum, wait for the menu to appear and then press ENTER. Then start the test cassette. After a short while, the words PROGRAM: Loading... should appear, and shortly afterwards some instructions will appear on the screen. Follow these to test the cassette unit.

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