Difference between revisions of "G"

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(GANG WARS)
(GANG WARS)
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'''DIAGNOSIS'''
 
'''DIAGNOSIS'''
  
Created a test Sequence for a known good VRAM (There are three in total on the board and one was failing). Ran the Test Sequence on the good VRAMs and both passed.
+
Created a test Sequence for a known good VRAM (There are three in total on the board and one was failing). Ran the Test Sequence on the good VRAMs and both passed. The same test sequence was then run on the failing VRAMS and on both occasions, pin 17 flagged up as fail. Although a couple of other pins failed they passed on retest however pin 17 on both faulty VRAMS refused to pass.
  
 
[[File:GWVRAM2.jpg|800x600px|Gwars VRam Test]]
 
[[File:GWVRAM2.jpg|800x600px|Gwars VRam Test]]
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[[File:GWRam.jpg|800x600px|Gwars VRam PCB]]
 
[[File:GWRam.jpg|800x600px|Gwars VRam PCB]]
  
Running same Test on the bad one, flagged up pin 17 as faulty. Refused to pass test.
+
Same test ran on third VRAM.
  
 
[[File:GWVRAM1.jpg|800x600px|Gwars VRam Test]]
 
[[File:GWVRAM1.jpg|800x600px|Gwars VRam Test]]

Revision as of 22:47, 3 October 2016

GANG WARS

FAULT

Board not booting up. Failing self check on VRAM

Gwars selftest

DIAGNOSIS

Created a test Sequence for a known good VRAM (There are three in total on the board and one was failing). Ran the Test Sequence on the good VRAMs and both passed. The same test sequence was then run on the failing VRAMS and on both occasions, pin 17 flagged up as fail. Although a couple of other pins failed they passed on retest however pin 17 on both faulty VRAMS refused to pass.

Gwars VRam Test

Gwars VRam PCB

Same test ran on third VRAM.

Gwars VRam Test

Tracing this pin showed it to be an address line that had no signal. Checking continuity showed that the pin should be connected to the 68000. It was open.


REPAIR

Soldered a wire link from the VRAM pin 17 to the 68000 pin. Board now boots into game. Still got sprite issues but now reliably booting up.

Gwars VRam Test