I bought this pretty rare Exzisus PCB as faulty from our member Corrado:

For the uninitiated it’s horizontal scrolling shooter arcade game released by Taito Corporation in 1987.There are two PCB version, one not JAMMA with separate RGB outputs for background and sprites, the other with a single video outputs and is JAMMA compliant.The one I got was the latter.

Once powered the board up I immediately noticed two issues : all sprites were horizontal lines shifted and repeated on each half of screen :

and  sound was missing at all (although I could hear some noises sign that amplifier was  good).Studying a bit the hardware, I could figure out how sprites were drawed.The four sprite EPROMS are addressed by a custom, marked ‘TC0010VC’ (there is another one for the backgrounds) while the data were written on two 6116 RAMs which were addressed by the same custom but not directly but through two 74LS273 latches and four 74ALS169 counters:

Probing the latter with my logic comparator I got troubles on the outputs of three of them so, although false readings are quite common for this kind of device I decided to remove them.Tested in my BK560A they all failed:

Once replaced these counters, the sprites were correctly restored:

So I could focus on the sound lack.Connecting an external amplifier to the analog output of the YM3012 DAC I could hear all the sound as well as on the input of the near TL074CN OP-AMP but nothing on its output :

This was confimed also on my analog scope (good input on the left, no output on the right):

Fitted a new TL074CN @J21 restored full sound.End of job.

 

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.

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.