JAMMArcade.net – Page 129

Point Blank repair log

PCB Repair Logs Comments Off

Nov 182015

I bought this faulty Point Blank PCB for cheap on Ebay:

Seller said it had graphical corruption and was missing a primary color and sound.When I powered it up I actually had sound but the other two issues were there:

The missing color was the green, tracing the pin 12 solderside back from JAMMA connector I found the culprit : one of the three SMD transistor ( each of which drives a color output) was missing:

Green was so restored :

but graphical troubles were still there.Inspecting the board I found that some pins of the custom C355 were smashed:

This custom handles the motion objects (sprites) and my issue concerned this part of graphics.Having a spare Namco NB-1 board I opted for a replacement of this ASIC :

After some work and pads rebuilding, I ended up with this result:

In this way graphics were completely restored but sprites had jailbairs:

Pressing down the board fixed the issue temporarily, inspecting again the board revealed a liften pin on a TC51832 (62256 compatible)RAM @12R:

Resoldered the pin and board 100% fixed.

Terra Force (bootleg) PAL dumps added

PAL Updates Comments Off

Nov 162015

Today I dumped the PALs from a bootleg of Terra Force.Original devices were two unsecured PAL16R4 whose dumps I successfully converted (using PALtoGAL utility) and tested into GAL16V8 targeting devices

Teenage Mutant Hero Turtles repair log #3

PCB Repair Logs 1 Response »

Nov 122015

Not a real repair but just a quick “dirty” fix for this Konami Teenage Mutant Hero Turtles PCB :

All was fine but the music played at the start of a game (when turtles jump from palace) was missing :

A usual I started my troubleshooting with a visual inspection and I found soon the culprit.One of the two 640KHz ceramic resonator was missing:

I took it from a dead donor board :

and once fitted the missing music was restored.End of (small…) job.

Golden Axe repair log #3

PCB Repair Logs Comments Off

Nov 092015

I had a spare Sega System16B ROM board type ‘171-5797’.Originally it mounted the E-Swat ROM set but I decided to convert to Golden Axe since I missed this game in my collection :

Atter burning the Golden Axe MAME rom set, I powered the board up and game was fully playable but with a noticeable sprites issue:

Judging from fault, I immediately thought about an addressing trouble of the sprite EPROMs (27C020 devices) so I went to check for continuity of their address lines.They were properly daisy-chained each other but the pin 30 (A17) of all of them was not connected to any pin of the ‘CN2’ interconnect (signal to address lines come from motherboard) :

Lack of signal on this A17 address line was confirmed also by my analog scope (good signal on left, bad on right of the picture below):

So, the trace had to be broken under the ‘CN2’ interconnect.Being not available schematics and wanting to avoid to desolder the whole connector, I soldered the end of a wire to PIN 30 of a sprite EPROM and with the other end I touched each pin of the ‘CN2’ interconnect that gave me no continuity until I hit the right one restoring correct sprites:

Lastly, I made the fix permament holding the wire with some hot glue:

That’s all for today.

Dead Connection PAL dumps added

PAL Updates Comments Off

Nov 092015

Today ‘coolmod’ sent to MAME Dumping Union mailing list the dumps from his Dead Connection PCB (two layer Japanese revision on Taito F2 hardware).Dumps were obtained from two PAL16L8 devices so I took care of converting them to GAL16V8 format.Replacements have been successfully tested by ‘coolmod’.Thanks to him for this contribution.

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