Neo Geo MV4F restoration - some community help appreciated

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    • Neo Geo MV4F restoration - some community help appreciated

      Hello everyone,

      last week I helped some nice unknown guy from the internet who lived 200 Km away to fix his cabinet. I just asked for money for gasoline and something to eat :) 8 hours later everything worked fine and he was really really happy and I had a lot of fun! We played too long and I sleeped in my car. At the next day he gifted me an non working 4 slot board and samurai showdown:



      Wow, what a nice guy!! He even donated me a little bit money :)

      The board itself has an calendar error, you will see why :D I'll document my work, so maybe it helps someone else. I'm by far no expert! I started with electronics at the end of last year. Just tell me if I'm doing something wrong!!



      The PCB itself was really dirty...


      If you look at the batterie area you can see the problem... so I removed the batterie.


      Oh boy, that was a mess. Now I started cleaning a bit using some isopropyl alcohol and noticed gloves are necessary. My skin started burning. Don't do my mistake, ware gloves from the beginning on!! Then I used a fiber pen to remove all this mess and I desoldered every component in the batterie area. Some of them felt to dust when I touched them...


      I ordered some new parts and cleaned the area using vinegar and waited 30 minutes to let the vinegar do its work. After that I used isopropyl alcohol to remove the vinegar, cleaned the board with distilled water, heated my oven to 70° C, turned it off and let my boards in there over night. I also covered the solder holes with some tape I cut out. Here is the result:

      The post was edited 2 times, last by DeWitt: spelling ().

    • I covered the outer are with tape and paper so I can spray paint it. So no conductor tracks are exposed.


      I used some two component clear coat spray paint. Worked nicely:


      Now I would like to do a batterie mod, but I have no idea how. I have a MV4F board and found no infos what todo.

      Does any one know it and can help me?

      Thank you very much for your help :)
    • So, if figured it out myself:-) I had to remove the 470 Ohm resistor. Here is the result:



      The solder pints on the top aren't that nice. I think it has something todo with the spray paint I used. But oll of the are nice at the bottom and all have good contact. I'm happy :)

      The battery and the holder will arrive tomorrow.

      The good thing is, everything works as before. So I still get and calendar error. That will be my next task.

      As always: I have no idea what I'll need todo but I'll figure it out. Any tips are welcome:-)

      The post was edited 1 time, last by DeWitt: spelling ().

    • Here a short update. I fixed the calendar error and use the Diagnose Bioas to test everything (except the sound...)

      I use the following resources to find the issue:
      wiki.neogeodev.org/index.php?title=CALENDAR_ERROR
      wiki.neogeodev.org/index.php?title=UPD4990


      This way I tested every trace and noticed that pin 6 which is connected to Neo-F0 pin 3 had no contact. This sounds easy, but it was not. I hat to find and understand the informations listed above...

      Then I also soldered the wire to pin 6 of D4990AC on the bottom side and I used a left over resistor leg and soldered a wire to it. I put it in one of the holes of the trace running to pin 3 of the Neo-F0 and soldered it into it.


      I don't now if this is the way you fix a broken trace... I did it and it worked! Pin 3 was just a little bit to small and on top of the board, so no :D



      I started the Diagnose Bios with the buttons ABCD pressed and started the calendar test, perfect. Every other test parsed too.

      After replacing the Diagnose Bios with a normal one and I started it... then I noticed the sound was too loud and I cloud not change the volume. Some isopropyl alcohol and sliding the volume slider a couple of times back and forth fixed it (board was turned off and waited until it was try before turning it on again).

      I was so happy that I tested every slot. The colors of this board are very good. My 6 slot board picture isn't that good and sharp, i don't know why?! After playing some games I noticed the board played sometimes a wrong sound snipped and some games crashed the sound. It turned the sound completely off until I rebooted the device... I think there is an other broken trace which flips some bits...

      Maybe I can use the Multi MVS cart form @Darksoft to run the sound test rom in combination with the Diagnose Bios. I need to find this out tomorrow!

      Thanks to @Frank_fjs who build the minigun I can use it now in combination with my monitor. This way I don't have to run back and force between living room whit my cabinet in it and my workbench which is located at an other floor :) Thank you!!!

      The post was edited 3 times, last by DeWitt ().

    • I followed the instruction @Darksoft provided, thank you very much :) Sadly it did not work to use the Multi MVS for testing... I think the reason is the following: the Diagnostics Bios does not wait until the Multi load it's ROM into the Flash... so it did not work :-/

      It worked on my normal board, I heard some strange testing sounds after loading the ROM into the flash of the multi. So in theory it should work :D

      Now I need someone to burn the Diagnostics Bios M1 ROM to a chip or a Z80 testing cart (would be even better) or I have to use my eyes to look for a broken trace, but I think I need a break. Maybe I wait until I receive the UniBios chips from @Sp33dFr34k, a really nice guy :)
    • DeWitt wrote:

      I think the reason is the following: the Diagnostics Bios does not wait until the Multi load it's ROM into the Flash... so it did not work :-/
      That sounds like the most probable reason.
      * Arcade-projects, the site where you get the most of your arcade games.
      * If you want Drama go to Neo-Geo forum ---Darksoft
    • ack wrote:

      Wanna give this version of the diag bios a try.

      mvs-scans.com/misc/19a00-t1.zip

      One of the things I modified in it a couple months ago was to not be so picky about the bios/m1 interaction. It will allow up to 5 seconds for the initial hello message from the diag m1.
      Sound promising! Thank you very much for your help, I appreciate it:-) Am I right that I need an new Diagnostics Bios chip to try this? Since I don't have an flash device I need to ask @Sp33dFr34k again if he could burn me one :S I'm not sure, maybe the was today at the post office... He is very very friendly but I'm not sure if I could ask him for an other favor... I don't want to take advantage of him either!!!!
    • DeWitt wrote:

      ack wrote:

      Wanna give this version of the diag bios a try.

      mvs-scans.com/misc/19a00-t1.zip

      One of the things I modified in it a couple months ago was to not be so picky about the bios/m1 interaction. It will allow up to 5 seconds for the initial hello message from the diag m1.
      Sound promising! Thank you very much for your help, I appreciate it:-) Am I right that I need an new Diagnostics Bios chip to try this? Since I don't have an flash device I need to ask @Sp33dFr34k again if he could burn me one :S I'm not sure, maybe the was today at the post office... He is very very friendly but I'm not sure if I could ask him for an other favor... I don't want to take advantage of him either!!!!
      Yeah, you would need a new bios chip for it. Just note that this is a work in progress update to the diag bios/m1. This is the full list of changes I've made over the stock version

      SP1: Re-implement color bars so they work on AES
      SP1: Add SMPTE color bars
      SP1: Go back to main menu after manual work/backup ram test
      SP1: Send error code to credit leds on MVS hardware
      SP1: Attempt to auto-detect if M1 is active (ie: on AES & MV1-B/C)
      SP1: Display when M1 is active
      SP1: Display slot number if a slot switch was done
      SP1: Display when SM1 tests were run
      SP1: Pressing ABCD after automatic tests will goto the main menu
      SP1+M1: Make 68k <=> Z80 communication test less finicky about timings
      SP1+M1: Split 68k <=> Z80 communication into 2 error codes (HELLO vs ACK)
      SP1+M1: SM1 output enable test
      SP1+M1: SM1 checksum test
      M1: Fix broken ram address test
      M1: Add ram output enable test
      M1: Add ram write enable test
      M1: Use rogue YM2610 IRQ as a way to recover from a failed slot switch
      M1: Fix looping forever waiting on unset of YM2610's busy bit

      Code for all this is at github.com/jwestfall69/neogeo-diag-bios if someone wants to mess with it.
    • ack wrote:

      DeWitt wrote:

      Do you guys even think I can fix this? I'm not that good with replacing chips and I don't have any spare chips. I also have not found any thing like this sound issue in the world wide web :D
      I would try cleaning the cart slots if you haven't already. @XianXi has a good video about how to do it.
      I use the geto version of an old Costco membership card with a torn up t-shirt wrapped around it soaked in 90% isopropyl.
    • I cleaned the slots like you suggested @ack using the method from @Kujako :D Here a my tools:


      The triangle hat a perfect tight fit. Sadly no changes at all... I tested every slot and nothing changed!

      I also noticed that the sound test does not output any sound... here is a video of it:
      dropbox.com/s/c0dow407k07s9rt/img_9085.mp4?dl=0

      Here is also an video of the mixed sound problem:
      dropbox.com/s/745r6wvesomjcq8/img_9086.mp4?dl=0

      I also noticed an cut trace on the sound slider in the analog area, I don't know how I missed that:

      I would say that can't be the problem, it's in the analog are.

      I also noticed something strange: the last days the right sound channel hat bad sound (some disturbing sounds) and the actual audio was quiet in the background. Today that disappeared when I plugin in my headphones via the 4 pin audio output. Now it is normal all the time. I don't complain, but thats not normal.

      I have also news about the new Diagnostics Bios @ack provided. @Sp33dFr34k burned one for me :thumbsup: I'll report how it will work with the Multi from @Darksoft. I'm looking forward to this!!

      Thank you all for helping me out!!

      The post was edited 1 time, last by DeWitt: spelling ().

    • Thanks to @Sp33dFr34k, the Diagnostics Bios arrived this weekend, thank you very much:)

      I soldered a batterie onto the MVS board (for config saving) and replaced the m1rom from joy joy kid: small ROM = fast loading : D Then I started the board, thanks to @ack the bios it’s much easier to navigate. I enabled "boot to game" with only one game configured and waited a minute or two to make sure the Multi loads the rom. Then I soft restarted the MVS board and pressed D to start the Z80 test. Thanks to @ack the bios waited some time and then started testing. This was the result:


      I also tried an random MVS cart, same result, different address… Since this is not an listed error, I think the bios can’t find it M1 rom for testing. Just a guess. What do you think @Darksoft? I think it's not possible to use the Multi for this test.

      Btw when I use the M1 Rom without the Diagnostics Bios I get the same sounds on this board and an other board I tested.

      I also ordered my self a Logic Probe and found out that the YM2610 does not output the bios testing sound. But I haven't tested further... I just found that out because I compared it with the YM2610 of an other board ;) Every testing tips are welcome!
    • looks like z80 and 68k cant communicate properly. I would test that first with an original cart. If the error is the same, most probably this is coming from the circuitry/shared ram between those 2. Could also be a bad z80.
      * Arcade-projects, the site where you get the most of your arcade games.
      * If you want Drama go to Neo-Geo forum ---Darksoft