Knights Of The Round Mame
Rosella Bowlan
Both of them had broken power ports so I figured it was a good time to try out a desoldering iron I purchased on ebay a while back. This might be my new favorite tool. Desoldering the power ports took around 1 minute each. If you have desolder things like ports I can definitely recommend this. I paid around $15 for it.
Looking at the rear of the cartridge PCB you can see that there is some sort of moisture/corrosion damage to the solder and trying to re-flow the solder is not really an option as it crumbles when you apply any heat.
I cleaned up the pins on the Mask Rom and to confirm it works I need to attempt to dump its contents.
Ristar uses a 42pin 16Mbit (2MB) Mask Rom which I found out is pin compatible with a M27C160 EPROM.
I did originally intend this thread just to be used for game cartridge repairs, but guessing I should just let it become a place for me (and others) to place their repair logs for anything video game related.
It is difficult for me to keep posting new repair logs as it is always preferable to not have to deal with broken games/hardware but if I see anything I want at a discounted enough price to make it worthwhile for me to attempt repairs I will.
I recently had the opportunity to pick up this arcade PCB that I had wanted for a long time at a very good price. However it was listed as having sound problems and for some reason had been returned by a previous buyer. The only thing I had to go from was the following images:
I had it returned not working only to find the rom chip had be taken? So my mate replace it with a spare rom top left hand side the music works fine it just when it says Mission 1 and when you jump up a buzz noise comes on and goes off if my mate had a eprom programmer he can do it?
I could see that the suicide battery Z80 processor with sound encryption had been replaced by a regular Z80 and that position A10 on the ROM board had been changed to an EPROM that is labeled: Shinobi A7 Sound Fix.
I could now see that the ROM PCB was a 5521 version and going from the Mask ROM positions I could deduce that this Shinobi was a Set 4 revision and this revisions suicide sound fix is a little different from the other game revisions and requires the non-encrypted epr-11361.a10 ROM from Shinobi Set 5 to work correctly.
I now suspected that there may be some broken traces underneath DIP Switch 1 and with the help of a SEGA System 16B schematic I found online I was able to tell that the DIP Switches connect directly to a resistor array 1 for 1 and then into a 74LS257 TTL IC:
Fortunately after testing continuity between switches 5, 6 and 7 I found that the traces between the switch and the resistor array was broken, so using some Kyna wire I bridged the connections on the bottom of the PCB:
Looking a bit closer you can see that pin 45 and 46 that are normally connected to ground have been cut, soldered together and connected to a +5v source to pull them high which is the older de-suicide method to run the CAPCOM B-XX custom IC without its volatile registers.
I also noticed that pin 60 is bent towards pin 61 and looks like they are touching which I was very concerned about, however thankfully after testing these pins in continuity mode on my multimeter I found that they are not touching each other and thus not an issue.
I cleaned up the original de-suicide mod but changed the pull up +5v source to the positive side of a diode which is better practice. Then I removed the green sticker that was covering up the CAPCOM custom IC to find out that it is a CPS-B-21 and not the CPS-B-04 that Varth should be using.
But first to ensure everything is good with both these B+C boards I removed all the EPROM and GALS and replaced them with ones from my Street Fighter II Turbo to see if it works perfectly and it does!
Due to them just being Zero ohm resistors I could safely use any old jumper wire to set them correctly but I just used some old capacitor legs and set them to the same as on my SF2 Turbo B board for JEDEC EPROM:
Knights of the Round is a CPS1 title that has a suicide battery and we can see that the battery has been removed from the C board and that a typical de-suicide mod has already been correctly performed to run its Custom IC sans any volatile security registers.
Knights of the Round C board uses a CAPCOM B21 Custom IC and IOC1 & C632 PAL IC which are identical to those on Street Fighter II CE/Turbo which uses a stock non battery B21, so I can easily swap over the C board onto my Street Fighter II CE B board to quickly test it:
Before I program anything I use my Top3000 universal programmer to dump the contents of the program EPROM at IC socket 22, which matches the CRC of the kr_22.7f binary file from the ETC/World/US version of Knights of the Round MAME ROM set and I also dump the contents of the 27c512 in IC Socket 9 which should be audio data but appears to be corrupt and mostly blank, likely from its EPROM window not being covered and long exposure to UV light.
I completely erase the 27c512 and using the appropriate files from the MAME knights.zip I program it and the two new 27c010 with the correct audio data. However, since the B21 no longer as the volatile security keys in its memory I have to source decrypted program ROM files for the game which along with a lot of other games can be found at The Dead Battery Society.
Placing my Street Fighter II Turbo B21 C board (and the one I used for Ghouls and Ghosts that has no kick harness for the extra buttons required for Player 3 inputs) results in perfect playback with no graphical issues:
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