So I just bought a bunch of ''new'' super nitendo S-WRAM chips from China. (pictures)

Discussion in 'Repair, Restoration, Conservation and Preservation' started by MaxWar, Feb 24, 2015.

  1. MaxWar

    MaxWar <B>Site Supporter 2013</B>

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    This I understand but they probably use the most basics of console functions just to get around the electronic tests just to make it more likely it that it can give you some info. It seems damaged SNES are seldom 100% dead, some games here and here half work or glitch around.
     
  2. l_oliveira

    l_oliveira Officer at Arms

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    Pay no mind to what the guy said. He knows nothing. :p

    The burn in or the other diagnosis cartridge performs a couple of tests on the hardware. The burn in cartridge is better because it can obviously loop the test until it fails (burn-in).

    It will catch errors like some CPU problems (stuff that don't prevent basic processing from happening), RAM/VIDEO RAM problems and some PPU/APU faults.
     
  3. abveost

    abveost Peppy Member

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    It's just code on a ROM on a cart. Any "electronic tests" required to run that which fail mean the console is too far gone to use the cart with.
     
  4. l_oliveira

    l_oliveira Officer at Arms

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    You're missing the point of the existence for any kind of diagnosis software.

    The point of that catridge is test the system for intermittent or partial faults. Also the burn-in exists for factory testing of newly produced units.
     
  5. abveost

    abveost Peppy Member

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    No I'm not. I've only addressed a question about whether the software would work on a flash card. Sorry if I didn't make that clear enough for you but that's not who my response was directed at.
     
  6. l_oliveira

    l_oliveira Officer at Arms

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    If Mario World works on the said flash cart, the two dumped test cartridge ROMs will work on the same flash cart too. There's nothing special about the hardware in the test cartridges.

    Edit: As MaxWar mentioned, there's a possibility that any eventual problem with the console might prevent the flash cart menu from starting. That would prevent anyone from using it with the test cartridge ROMs. So it's best have them on a real ROM cartridge.
     
    Last edited: Mar 6, 2015
  7. LeHaM

    LeHaM Site Soldier

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    ANYWAY...
    MaxWar do you have a working snes? Try the new ram on a known working console, that'd show if the chips are indeed good :)
     
  8. MaxWar

    MaxWar <B>Site Supporter 2013</B>

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    Yeah I have several working SNES.
    I may try that eventually but for now I am waiting to get a test cart reproduction.
    I think the RAM is good. It did not make any change in behavior of the SNES. It is still faulty and still half runs some games. If the RAM was bad or the install was bad I would have expected further deterioration of the operation of the console.

    Likely the ram was good prior to my attempted repair and I swapped it for some other good ram. Hence no change in the symptoms.
     
  9. MaxWar

    MaxWar <B>Site Supporter 2013</B>

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    Update time:

    I just got myself a Nintendo Burn in test cart reproduction, Thanks to TheRealPhoenix for the Work and Helder for the reference.
    Cart works great on a Healthy SNES but unfortunately I have not been able to use it on my faulty boards.

    One of my board will actually run some games so it is not completely dead and I was hoping the burn in test could reveal something but not.
    It loads the Cart menu but as soon as I pick an option it crashes. On the board where I replaced the ram it won't run at all.
    This is a bit of a deception but hey at least I have a test cart now and maybe it will be useful eventually.
     
  10. MottZilla

    MottZilla Champion of the Forum

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    The next step is you can learn to program for the SNES and see what exactly makes each unit fail. ;)

    Also, for most games it's extremely common for music to continue to play even if the game crashes. The sound processor and memory for it are very isolated from the rest of the system. Now if you could get an idea of what a game or program is doing when it fails that might give insight on what could be the hardware failure. I don't know the whole story behind your bad SNES boards but have you also checked to verify all the address lines are intact and reach from the cartridge port to the CPU and other components? That's just one idea of why some games would run partially but then fail.

    Perhaps a test rom exists that could test if memory is being addressed properly. I know one exists for trying to determine memory mapping.
     
  11. MaxWar

    MaxWar <B>Site Supporter 2013</B>

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    While I am quite motivated at getting stuff fixed, I do not think I will go as far as learning to program :p

    The story behind my faulty SNES is that I regularly buy Junk console lots on ebay and locally. I refurbish them and resell them on ebay.
    While most such consoles typically are fine after a good clean, I do get some with funny issues. At this point I have a decent stack of funny snes boards.

    Of course I always do a good clean and visual inspection on the boards. I have fixed stuff with broken traces before but the SNES I have been working on lately do not look like they have any corrosion or damage on the boards.

    I am to soon purchase an Eprom programmer, have been wanting to for years. I may end up experimenting with other version of the SNES test carts and It could be very nice to find specific test roms to test the console.
    I do get a high from fixing stuff.
     
    Last edited: Mar 13, 2015
  12. jonoghue

    jonoghue Active Member

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    did you ever figure out what was wrong with your SNESs with the black screens? i have 2 SHVC SNESs with the same issue. never any sound, but some games show random graphical glitches, and i havent found any games that run to any extent.

    i've been asking people on this thread http://assemblergames.com/l/threads...ith-black-screen-problem-trying-to-fix.56488/
    but have only gotten as far as "replace the caps". OP even has FOUR of these "black screen of death" SHVC SNESs. i've got a set of caps on the way but from your experience i guess it's unlikely to work. i was almost sure it would be an S-WRAM issue and got excited when i saw this thread. at this point i guess it's gotta be the CPU but i'll go ahead with the caps anyway.
     
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  13. MaxWar

    MaxWar <B>Site Supporter 2013</B>

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    I tried getting my hand on spare SNES CPUS and did find some sellers who claimed to have them but they were mostly asking too high a price. Like I am going to pay 30 USD for a snes CPU when you can get a working spare console at that price.
    One seller however offered them at 5$ If I purchase 10 or more but they insisted on Western Union for the payment and refused paypal. So yeah, red flag, I did not buy.

    I want to do an experiment eventually where I will swap cpus between 2 glitching snes. I know that wont fix anything but if the symptoms transfer with the CPUs that will be proof that the problem is indeed within the CPU. I am still a bit disappointed that the burn in test cart did not help.
     
  14. jonoghue

    jonoghue Active Member

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    sounds like an interesting experiment... might have to try that myself...
     
  15. MaxWar

    MaxWar <B>Site Supporter 2013</B>

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    An interesting thing with those black screen SNES is how if you keep trying games on them you will very often find one game that half works or crashes instead of the black screen. From one snes to the next they will often not be the same games at all. It can litterally be one game on 20 that just ''does'' something. But this might be useful in troubleshooting the root of the problem.

    Im really chewing more than I can bite with my life right now so Im not sure when I will have time to do this. But I sure want to try the CPU swap experiment.
     
  16. l_oliveira

    l_oliveira Officer at Arms

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    The burn in cart isn't a silver bullet but it has helped me to fix countless systems. It needthe CPU to be good enough to allow it to boot, though.

    If the burn in cart didn't boot I would replace the CPU right away. That always worked wonders for me.
     
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  17. MaxWar

    MaxWar <B>Site Supporter 2013</B>

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    You know at this point I have like 8 of those dead snes motherboards. 7 of them wont even boot the menu of the burn in cart. One gives me the menu but it freezes as soon as I start the burn in test. Interestingly they are all of the early SHVC CPU variety. I dont seem to encounter much problems with the later SNES revisions. But your comment gives me some hope that I can get those things fixed if I manage to find some CPUs. Thanks again!!
     
  18. jonoghue

    jonoghue Active Member

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    I had a thought, what if it's a problem with that batch of CPUs? it seems like this has been happening long enough for it to start affecting the later revisions. So i looked in both dead SHVCs and my personal SNS-CPU-GPM-02 and get this. the SHVC models had
    "CPU A" in them. mine has "CPU B" in it. i'm willing to bet CPU A had some kind of flaw in it that was corrected in the later revision, that is resulting in dozens of dead consoles. if you find some CPUs let me know. And if you can, try to get the B versions.
    Also, if you don't mind, could you check the CPUs in your SNESs and see if they're all S-CPU or S-CPU A?
     
    Last edited: Aug 15, 2015
  19. MaxWar

    MaxWar <B>Site Supporter 2013</B>

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    The same thought had occurred to me. Its seems very likely from the statistics alone that the Early SHVC models have lower long term reliability than later models. Even if they are a couple years older, this does not account for the large discrepancy between the amount of dead consoles of each revisions.
    I just checked 4 broken SHVC motherboards I had already taken out of the consoles and all of them are CPU A.
    Another good clue is that one of them will boot most games but not all. Most that boot will crash quickly but some seems to be running normally. However I cannot get the controllers to work no matter what I tried. I ruled out issues with the controller themselves, the face plate, the ribbon cable, all are good. I traced the board and everything is mint. The controllers connect directly to the CPU A, which I even reflowed to rule out cold solder joints. This seems like a good clue that the part itself is faulty.
    My intuition tells me that the CPU A are indeed failing on all these SHVC. But this is only intuition until science demonstrates it.
     
  20. l_oliveira

    l_oliveira Officer at Arms

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    I'll drop this here as a example of what I've been talking about

    http://nfggames.com/forum2/index.php?topic=2916.0

    That particular problem, with MODE7 on SFC/SNES was caused by the PPU1 chip failing. Because it was still working good enough to allow the system to boot, the test cartridge worked fine with the console and it even passed all tests. But the visuals of the burn in test would display faults during the use of MODE7 effects.

    The test cartridge can test ram, check if certain registers are behaving properly (particularly the sprite stuff aka "OAM") and the sound module.

    If I remember it well, when the sound module is completely unresponsive the test cartridge will hang at a black screen when you attempt to use any of it's options, just like most games do when it's disconnected.
     

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