Oct 142015

I got this Toaplan Knuckle Bash from my friend Josef for a repair.

Knuckle Bash PCB

He said board showed graphical issue which he could clear only by raising the 5V to +5.5V.After powered it up I had confirm of what he told me, actually colors were bleeding (you can notice it on right part of the picture below):


Schematics for this board were available so I could identify the part of circuit which generates the color palette:


Data from the two 6116 SRAMs are latched by two 74LS273 (actually my board mounted two 74HCT273).When I went to piggyback the one @U9, colors were restored.I desoldered the IC but it succesfully passed the test in all my programmers, also comparing it with a good one on a tracer showed no abnormality:


Probably it was not really bad but its thresholds were altered.Despite this, I socketed and replaced it:


Another cool game fixed.


 Posted by at 10:35 pm

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