https://wiki.arcadeotaku.com/index.php?action=history&feed=atom&title=Dragon_Ball_Z_Repair_LogsDragon Ball Z Repair Logs - Revision history2026-05-08T08:12:09ZRevision history for this page on the wikiMediaWiki 1.42.1https://wiki.arcadeotaku.com/index.php?title=Dragon_Ball_Z_Repair_Logs&diff=7671&oldid=prevDavewellington: Created page with "'''Repairer:''' [http://www.aussiearcade.com.au/member.php/3590-cal2 cal2]<br> '''Forum Thread:''' [http://www.aussiearcade.com.au/showthread.php/29386-Dragon-ball-z-repair-lo..."2012-09-13T00:50:59Z<p>Created page with "'''Repairer:''' [http://www.aussiearcade.com.au/member.php/3590-cal2 cal2]<br> '''Forum Thread:''' [http://www.aussiearcade.com.au/showthread.php/29386-Dragon-ball-z-repair-lo..."</p>
<p><b>New page</b></p><div>'''Repairer:''' [http://www.aussiearcade.com.au/member.php/3590-cal2 cal2]<br><br />
'''Forum Thread:''' [http://www.aussiearcade.com.au/showthread.php/29386-Dragon-ball-z-repair-log Dragonball Z PCB Repair]<br><br />
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'''Symptoms'''<br><br />
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Repeating graphics on first scroll plane:<br />
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[[File:Pcb repair dragonball z 1.jpg]]<br />
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[[File:Pcb repair dragonball z 2.jpg]]<br />
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'''Repair'''<br><br />
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Based on the mame driver, I found that the graphics for this plane come from 222a09.25l (K053536 PSAC-2 #2).<br />
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The board passes the PSAC2 rom test, so I assumed the mask rom is good. Note that the pinout is compatible with M27C160.<br />
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I reproduced the problem on mame by changing the way the pixels bits are fetched from this eprom.<br />
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Normaly it should be:<br />
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0 1 2 3 4 5 6 7 8 9 a b c d e f<br />
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But is displays like this:<br />
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0 1 2 3 0 1 2 3 8 9 a b 8 9 a b<br />
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In binary this means:<br />
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3210 3210<br><br />
0000 0000<br><br />
0001 0001<br><br />
0010 0010<br><br />
0011 0011<br><br />
0100 0000<br><br />
0101 0001<br><br />
0110 0010<br><br />
0111 0011<br><br />
1000 1000<br><br />
1001 1001<br><br />
1010 1010<br><br />
1011 1011<br><br />
1100 1000<br><br />
1101 1001<br><br />
1110 1010<br><br />
1111 1011<br><br />
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So it means bit 2 is likely stuck to 1 or 0.<br />
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Since the tiles are 16x16 in 4bpp, this means b0 isn't used. So, if b1 = A0 it means b2 = A1 on the mask rom.<br />
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Looking at A1 using a probe, i found it was bad compared to the other signals. It should be a squared signal of 1/2 frequency of A0. Instead, it is pulsing very quickly.<br />
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So A1 is bad. A1 is connected to O3 of 27F374 @ 24M.<br />
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I changed the IC to see but it didn't make changes.<br />
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After taking time tracing the board, I found that a pin of the custom chip 053936 @ J16 was desoldered and made contact to an other pin.<br />
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Fixing this pin, also fixed the graphic problem <br />
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'''Repair Logs converted to wiki format by Brad from [http://www.aussiearcade.com.au Aussie Arcade]'''.<br />
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[[Category:Repair Logs]]</div>Davewellington