Subject: Re: DEFENDER diags help needed
From: [email-masked] (Aaron Liddiment)
Date: Tue, 3 Jan 1995 00:01:01 +0000
Newsgroups: rec.games.video.arcade.collecting

David Fish ([email-masked]) wrote:

:    The self test tells me that there is a failure and the four led's on the
:  ROM board display as shown below. My question is - what does it mean?
:  I'm guessing that it signifies a RAM error. Anyone know?

Here are the self test extracts from the Defender booklet:-

POWER-UP AND RAM/ROM TESTS
==========================
Test initiated at power turn-on and after depressing RESET pushbutton on
CPU/VIDEO board.

   RESULT     CRT INDICATION     LED INDICATION         
   -----------------------------------------------------
   Pass       INITIAL TESTS OK   4 LEDs blink twice
   Fail Ram   RAM TEST FAILED    X--X (LEDs 1 & 4 light)
   Fail Rom   ROM TEST FAILED    None

   In either of the above two 'Fail' situations you should depress ADVANCE
   in MANUAL-DOWN while the failure message is displayed to enter
   Diagnostics.

ROM DIAGNOSTICS - TEST 1
========================
 From game over, depress ADVANCE in MANUAL-DOWN.

   RESULT   CRT INDICATION    LED INDICATION       CORRECTIVE ACTION
   -----------------------------------------------------------------
   PASS     ALL ROMS OK       X---                 n/a
                              LED 1 blinks twice
   -----------------------------------------------------------------
   FAIL     ROM TEST FAILED   X---                 Replace ICX on ROM board
                   X          LED 1 lights         or depress ADVANCE in
             (X = 1 to 12)                         MANUAL-DOWN.
                              Chip indicated:      Replace:
                                ---X                 IC1
                                --X-                 IC2
                                --XX                 IC3
                                -X--                 IC4
                                -X-X                 IC5
                                -XX-                 IC6
                                -XXX                 IC7
                                X---                 IC8
                                X--X                 IC9
                                X-X-                 IC10
                                X-XX                 IC11
                                XX--                 IC12

RAM DIAGNOSTICS - TEST 2
========================
 From ROM diagnostics depress ADVANCE in AUTO-UP.

   RESULT    CRT INDICATION   LED INDICATION       CORRECTIVE ACTION
   -----------------------------------------------------------------------
   TESTING   Random Pattern   n/a                  Depress ADVANCE in AUTO
                                                   to bypass test
   -----------------------------------------------------------------------
   PASS      ALL RAMS OK      -X--                 n/a
                              LED 2 blinks twice
   -----------------------------------------------------------------------
   FAIL      RAM FAILURE      -X--                 Replace RAM (see below)
                 XY           LED 2 Lights         or depress ADVANCE in
             X=Bank No.                            MANUAL-DOWN
             Y=Chip No.       --------------------------------------------
                              Bank indicated:      Depress ADVANCE in
                              X--- = 1             MANUAL-DOWN
                              -X-- = 2
                              --X- = 3
                              --------------------------------------------
                                                   Replace in Bank:
                              Chip indicated:      1    2    3
                              ---X = 1             4L   5L   6L
                              --X- = 2             4M   5M   6M
                              --XX = 3             4N   5N   6N
                              -X-- = 4             4O   5O   6O
                              -X-X = 5             4P   5P   6P
                              -XX- = 6             4Q   5Q   6Q
                              -XXX = 7             4R   5R   6R
                              X--- = 8             4S   5S   6S

CMOS RAM DIAGNOSTICS - TEST 3
=============================
 From RAM diagnostics depress ADVANCE in AUTO-UP.

   RESULT   CRT INDICATION         LED INDICATION       FAULTY AREA
   -------------------------------------------------------------------------
   PASS     CMOS RAM TEST PASSED   --X-                 n/a
                                   LED 3 blinks twice
   -------------------------------------------------------------------------
   FAIL     CMOS RAM FAILURE       --X-                 CMOS RAM 1I,
                                   LED 3 lights         memory protect gates
                                                        2H, 1K or address
                                                        decoder 2F, 4E.
            ----------------------------------------------------------------
            CMOS INTERLOCK FAIL    --X-                 Coin door interlock,
                                   LED 3 Lights         memory protect gates
                                                        1J, 1K, 2H or CMOS
                                                        RAM 1I.

I hope these help you find your problem :-)