Seibu ‘UEC-52’ reproduction by Caius

    This site uses cookies. By continuing to browse this site, you are agreeing to our Cookie Policy.

    • Seibu ‘UEC-52’ reproduction by Caius

      THIS IS A REPRODUCTION PROJECT MADE BY @caius ALL INFORMATION HAS BEEN POSTED WITH HIS PERMISION. CREDIT AND MERIT GOES TO HIM.

      This project started when, during my repairs, I came across these two PCBs.
      Blood Bros:

      Raiden:

      Both were faulty.Blood Bros played blind :

      While Raiden lacked of the BLUE color:

      The culprit was the same in both boards, the ‘UEC-52’ (sometimes silkscreend on PCB as ‘HB-52’):

      It was clearly faulty in Raiden and missing at all in Blood Bros:

      This custom in SIL package is an RGB DAC responsible to convert the digital signals of color palette circuit into analog, it’s used on some Seibu/TAD Corporation PCBs like :

      Raiden
      Blood Bros
      Sky Smasher

      Some time ago I partially figured out the pinout and schematics/parts after removed some of the epoxy resin that encapsulate it:

      As you can see it’s a 15 bit DAC whose design resembles the Taito ‘TC0070RGB’ : two octal D-type flip-flops , some printed film resistors (with typical values of 4K, 2K 1K, 470 and 220 for the 5 bits of each color) forming resistor ladders before the output to JAMMA RGB pins.But there was also a third IC that I could not identify.At first glance I thought about some kind of darlington array to amplify the signals so I made a post on EEVblog asking for some help:
      eevblog.com/forum/projects/how…plify-ttl-logical-levels/
      The user ‘stj’ (thanks again to him) pointed me in right direction suggesting that the unknown IC could be a 74LS367 used for video blanking.So I removed the IC from a workingcustom and was able to identify it as a 74HC368:

      At this point I had all the info to complete my schematics in order to design a replacement, obviously I first made some prototyping on breadboard which went fine.Later I sent my project files to China for manufacturing and got the bare PCBs after some weeks:

      Time to populate (in my design I used 74HC574 since it has more logical pinout compared to 74HC374)

      Here is a side-by-side comparison:

      Testing was successful on both boards (excessive brightness of recordings is an issue of camera, video levels are exactly the same of original part)


      See you to next reproduction project!
      * Arcade-projects, the site where you get the most of your arcade games.
      * If you want Drama go to Neo-Geo forum ---Darksoft