Dreamcast region free BIOS

Discussion in 'Sega Discussion' started by FireAza, Jun 28, 2012.

  1. Bad_Ad84

    Bad_Ad84 The Tick

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    pad 7 of the bios is A4

    Pin 17 is A4 on the IC502

    Connect them together, as they are on the same bus.

    I can also make out the trace just from your low res picture.... you might need glasses! lol
     
    Last edited: Aug 16, 2012
  2. FireAza

    FireAza Shake! Shake!

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    I see, thanks Bad_Ad! What do you think about the idea I posted on the previous page? Would that not work? Not that I don't trust you, but following the trace myself, I could swear that pin 17 (counting from 20, right to left) on the IC502 leads to pin 8 on the IC501. And I'm using a magnifying glass here :p

    As to needing glasses, I wear contacts, but I think they need to be replaced :p
     
    Last edited: Aug 16, 2012
  3. Bad_Ad84

    Bad_Ad84 The Tick

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    What idea? Connecting it to pin 7?

    Why would that work? you dont just connect up pin 7 to leg 7... the chips have completely different pin out. Following that logic, Pad 44 will connect to leg 44 on IC502, which doesnt exist.
     
  4. Bad_Ad84

    Bad_Ad84 The Tick

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    Here is how I am seeing it:

    If you have a multimeter, you can confirm by checking for continuity between the via right next to pad 7 that you ripped off (the little hole above it) and check that to pin 17 on IC502. It should be directly connected.
     
    Last edited: Apr 5, 2016
  5. FireAza

    FireAza Shake! Shake!

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    Actually, my idea was more like this:
    [​IMG]

    But it would probably be best to go with what you're suggesting ;)

    *EDIT* I've checked the trace with a multimeter, and unless I'm completely failing at using a multimeter (I've only just purchased one recently so it's possible!), it's responding on leg 16 and not leg 17 :\
     
    Last edited: Aug 16, 2012
  6. Bad_Ad84

    Bad_Ad84 The Tick

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    What you suggest is how I would do it.

    If you think your soldering is up to it, then do it like that.
     
  7. FireAza

    FireAza Shake! Shake!

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    Sweet, that also solves the problem of if pin 7 is connected to pin 16 or 17 too :D Thanks again for your help Bad_Ad!
     
    Last edited: Aug 16, 2012
  8. Bad_Ad84

    Bad_Ad84 The Tick

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    Are you sure you are counting the pins correctly?

    it should be the 4th one from the right

    17 18 19 20

    Common mistake is counting 3 back from 20 to get to 17
     
  9. FireAza

    FireAza Shake! Shake!

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    Pretty sure I'm counting it correctly. The pin that's responding is next to the pin with the white dot (pin 15 I'm assuming) on the right. This also is the pin that I'm arriving at when I follow the trace from the broken pin (damn you white text!)

    Either way, I think the easy and safe option is to do what I depicted in the picture above :)
     
    Last edited: Aug 16, 2012
  10. Bad_Ad84

    Bad_Ad84 The Tick

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    I will check a board when I get home - just out of curosity sake.

    Its possible the address lines do not match 1:1, but I was pretty sure they did.
     
  11. FireAza

    FireAza Shake! Shake!

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    You can color me confused too ;)
     
  12. FireAza

    FireAza Shake! Shake!

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    Well, I've installed the new BIOS. The DC hasn't exploded and the main menu loads, so I think it was a success :D
     
    Last edited: Aug 17, 2012
  13. Bad_Ad84

    Bad_Ad84 The Tick

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    It does indeed connect to pin 16 (A5) rather than A4.
     
  14. FireAza

    FireAza Shake! Shake!

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    Ha! I knew I wasn't crazy!
     
  15. AlmostOriginal

    AlmostOriginal Spirited Member

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    I recently fitted the region free bios inside my PAL Sega Dreamcast VA1 (Removed the whole chip). It boots the logo spins the disk but after that the screen goes black. If i open the lid i see the logo and get to the dashboard. (It worked fine before i replaced the chip)

    The problem is that the system runs about 10 -15 seconds before it goes to black screen.

    I mounted the region free bios 99% similar to my other motherboard (VA1) and it works perfect.
     
    Last edited: Mar 23, 2013
  16. omp

    omp Familiar Face

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    Possible dry solder joint fault is not there until it "warms" up.
     
  17. AlmostOriginal

    AlmostOriginal Spirited Member

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    Sorry but i dont get it?
     
  18. omp

    omp Familiar Face

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    Solder joint is not making a good/firm/electrically sound connection.

    Do you have a magnifying glass? You may have to go over your connections again, which is as simple as re-flowing the solder.
     
  19. beharius

    beharius Resolute Member

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    2 of my Black Sports DCs had that exact problem. It`s not about cold solder joint, I checked it multiple times, nada, it`s really weird, when I put the original one back, it works but not the region free one. I modified many consoles with this bios before, but somehow some consoles are not compatible...
     
    Last edited: Mar 24, 2013
  20. Bad_Ad84

    Bad_Ad84 The Tick

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    Ive modified hundreds, not 1 has had an issue yet.

    Id like to see one of these "incompatible" units....

    But you should just do the piggy back install, then you can try other bioses (i.e. dump the original then patch that to be region free etc)
     
    Last edited: Mar 24, 2013

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