Caius Arcade Repairs & Engineering: Vendetta repair log

Yet another PCB bought in a lot, a Konami Vendetta :

The board was in good shape but played almost 'blind' as most of graphics was missing :

I experienced this kind of issue different times on other Konami boards like in these past repair from me (thanks to Porchy for allowing hot links from JAMMArcade)

https://www.jammarcade.net/the-simpsons-repair-log-3/

https://www.jammarcade.net/g-i-joe-double-repair-log-3/

The cause was due to a bad '053251' custom ASIC :

As MAME source says, this custom takes on input different layers of graphics as well as some priority bits and outputs 11 bit of palette index plus two shadow bits :

Probing the outputs revealed they were dead, stuck at LOW or HIGH logical level :

Having a spare I decided to replace it :

I soldered down the spare repairing a lifted trace at same time (some green lacquer used to hold the wire in place) :

In ths way most of graphics were restored but the sprites were wrong with parts of them spread on the screen :

I launched a MASK ROM check which reported three bad 8Mbit devices :

This was possible but unlikely although we all know Konami MASK ROMs are prone to failure.

On this board and similar hardware the sprites generation is entirey handled by a couple of surface mounted custom ASICs.Specifically the '053246' generate the addresses for the MASK ROMs and the '053247' processes their data :

Judging from the issue (parts of sprites misplaced on screen) I was more inclined to think about an addressing problem hence I decided to replace the '053246'.It came off quite easily with my hot air station :