This one came from the same lot of faulty PCBs (seven in total) as the previously repaired Growl.For the uninitiated, Cadash is an action game with some RPG elements.
Board was in good shape (it has also additional hardware for multi-link game) .
When powered on I got this screen:
There was a clear problem with main code execution so I dumped the four program ROMs and none of them matched the ones in MAME.I ran these dumped ROMs in MAME and I got a similar error (different memory address due not perfect emulation of 68000 core, I guess):
This was enough to lead me to reprogram the four program ROMs from cadash World set into 27C010 devices.And this was the winning move which fixed the board.
Yesterday I got a lot of faulty original PCBs.Among these there was a clean Growl PCB.I always like this game (and played it in MAME) where the player controls a forest ranger who must protect the local wildlife from a group of evil poachers who are driving the animals to extinction.
As said, PCB was in mint state:
but once powered up it showed garbled sprites:
I noticed that, if I press the PCB in the area near the ASIC marked ‘TC0540OBN’ @IC25, all the sprites were restored.
So ,after a quick consultation of MAME source that confirmed this ASIC as a sprites generator ( the letters ‘OB’ in the ASIC name stand for objects a.k.a. sprites), I understood this was the way to follow in my repair.Probing the tightness of the individual pins with a needle I found some lifted ones.A reflow with my hot air station at 390° and a bit of flux was enough to fix the sprites issue completely.
Got today in the mail this mint original Konami X-Men PCB bought as faulty:
Once fired up I got this:
So, RAM/ROM test reported a bad IC @37F but this was not the real location of the IC since there was no location 37F on PCB.So, clearly there was some trouble in the tilemap generation, this was confirmed by the word “BAD” which became “BCF”.So, I launched MAME:
and, comparing the emulator and real PCB test results screens, I could identify that the faulty IC reported by test was the Panasonic MN4464 (6264 compatible) SRAM @ 15F
This confirmed my theory about bad generation of tilemaps since this SRAM is used by the near ‘052109’ ASIC (tilemap generator).
So, time to desolder the IC and test it out of circuit corfirmed the RAM as bad:
Fitted a socket and a spare 6264 SRAM and I could add also this cool game to my growing collection!
This is the second Lethal Enforcers PCB I fixed and also in this case it has been a pretty easy repair .
Board was mint and clean:
When powered up it I got this screen:
Screen was static but from the clicking sound I understood that watchdog was active so, for first, I disabled it by closing jumper ‘JP’ near JAMMA edge.In this kind of Konami hardware (like in many others) RESET is generated by pin 10 of the SIL custom ‘051550’.Probing this revealed that signal was good (first LOW and then HIGH) while RESET line (pin 37) of the main CPU HD63C09EP was stuck LOW.I traced it back to a 74LS367 @N6 which output was good and input of this to an output (pin 13) of 74LS164 @H3.Tested this with HP10529A logic comparator revelead bad outputs (pin 11, 12, 13).
So I desoldered and tested it in my EPROM programmer and B&K Precision 560A IC tester which confirmed it as bad:
Stored this original Galaga PCB from a while but never looked at it deeply:
It had a piece of tape on it saying “Dead” but at a first visual inspection I noticed it missed the custom marked ‘0020’ (tilemap address generator with scrolling capability) on CPU board @1H.So I thought game is over, I was doomed .The only chance I had was using some modern replacement (based on CPLD or FPGA).But, then, my savior appeared under the name of Silvio, a guy met over over ArcadeItalia forums (thank you again and again..) who very kindly donate me this custom chip.
So, time to build the needed JAMMA adaptor and I fired up the board getting this:
Horizontal white stripes all over the screen, a good point to begin from 🙂
So, I started to touch and press the board in different places and I noticed that if I pressed the custom marked ‘0200’ (GFX data shifter and mixer) @4H on video PCB , issue disappeared.So, it was clearly a matter of bad contact due a corroded socket and this was confirmed by replacing it with a new one:
I was happy since I thought board was 100% fixed but when I started a game I noticed (or better, heard..) something odd : all sound FX (explosions, etc..) were fine but music was muffled, almost distorted.
So , schematics in hand, I was starting my troubleshooting on audio section when I noticed that a 1KOhm 5 pin resistor network @RM2 was missing from my board:
Looking at schematics I found that this should have been connected (and acted as pull-up) to outputs of the near N3101AN (7489 equivalent) @2A which is one of the two RAM used in sound circuitry .So, with confidence I installed a new resistor network and…. music really came back crystal clear as it should be.
