Seriously, what the hell is this thing?

VGS_MrMark0673VGS_MrMark0673
in Collector's Corner
I'll cut to the chase...

I was opening up some donor carts for our next FNP project with Matt today and we stumbled across this:

image

I know it's not a proto, and that isn't an EPROM chip, so what the hell is it?  Judging by the back side, I have a hard time thinking this is a repair job as the solder work definitely does not look hand done, but it has a giant sticker on it the likes of which I've never seen.  I've opened up a whole but of Golf cartridges between this project and Hoppin' Mad and I've NEVER seen something like this.

Is this thing an EEPROM chip?  Anyone else ever seen anything like this?  Thanks guys!

Comments

  • PenguinPenguin
    My guess would be that it was either a factory defect that was repaired in product testing, or it was repaired at a service center. never seen anything like that before thou.
  • LimbofunkLimbofunk
    As far as I'm aware, that wouldn't have to to with a Service Center repair...they received the same chips that were factory made and had the same markings as the original products.  I have tons of chips, and the ones for NES games that I have are identical to the ones on the board themselves.
  • VGS_MrMark0673VGS_MrMark0673
    Hmm, interesting information guys. If it were a factory defect, would it likely have been soldered by hand during a repair? Looking on the solder side, it seems unlikely that it was done by a person.



    Anyone else with extensive PCB experience ever seen anything like this? i don't really want to use this as a donor cart if it is the first instance of a chip like this being found.



    Where is Bootgod when you need him?
  • NationalGameDepotNationalGameDepot
    I have opened a few thousand games over the years, and I have never seen one of these either. I have no idea what it is from though.

    ~~NGD
  • blarkyblarky

    The one with the white sticker is (M2764  CHR) is a 65536 bit UV eraseable Read Only Memory.

    The one with without the sticker (M38128B   PRG)  is a 16k ROM

    Also, found this on PRG (program ROM) and CHR (character ROM)

    http://assemblergames.com/forums/archive/index.php/t-10230.html

  • VGS_MrMark0673VGS_MrMark0673
    Originally posted by: blarky

    The one with the white sticker is (M2764  CHR) is a 65536 bit UV eraseable Read Only Memory.



    I really don't know about this, I'm 99% sure this chip isn't windowed.  Is there a flashable chip, EEPROM chip, or masked ROM chip that would use the M2764 number to identify itself?  If it's an EEPROM or a Flash chip, I can deal with that, but an EPROM doesn't seem logical.
  • blarkyblarky
    Originally posted by: MrMark0673


    I really don't know about this, I'm 99% sure this chip isn't windowed.  Is there a flashable chip, EEPROM chip, or masked ROM chip that would use the M2764 number to identify itself?  If it's an EEPROM or a Flash chip, I can deal with that, but an EPROM doesn't seem logical.




    Googling 'M2764', I get multiple hits from different manufactuers that it's an UV EPROM.  I didn't get an exact hit for 'M2764ZB', so the ZB could be a slight variation.

    http://www.alldatasheet.com/view.jsp?sSearchword=M2764

    http://www.chipdocs.com/datasheets/datasheet-pdf/SGSThomson-Microelectronics/M2764.html

    http://kazus.info/datasheets/search/go/?query=M2764&h=1&nohistory=1

  • VGS_MrMark0673VGS_MrMark0673
    Yeah, it's 100% definitely not a UV erasable EPROM chip, that much I've known. No window = no UV light ever getting into this thing.
  • mark_kmark_k
    You could take of the label and see exactly what's printed on the chip itself. The full part number and manufacturing date code could be useful. It's probably an OKI MSM2764 OTP EPROM. OTP means one-time-programmable; the same chip as a normal UV EPROM, but in a plastic package, not a ceramic windowed package.

    As to what it's doing in that Golf PCB... well I have a couple of guesses. One would be that it was like that from the factory. Maybe Nintendo ran out of Golf CHR ROM chips, and used EPROMs while waiting for the next batch of mask ROMs to come in?

    Or the cart could have been repaired by a Nintendo service center. They were able to order individual ROM chips. Perhaps at the time it was repaired, Nintendo had run out of Golf CHR mask ROMs, so the replacement parts were EPROMs?

    I have a PAL Mike Tyson's Punch-Out!! cart which has an EPROM in. Like your Golf PCB, it doesn't look hand-soldered.

    Most service centers, especially by the time of the SNES with its surface-mounted chips, would have had some kind of hot-air soldering device which could explain how neat the soldering looks.

  • VGS_MrMark0673VGS_MrMark0673
    Damn Mark, very informative post! An OTP EPROM seems perfectly reasonable with the part number and the material the chips is made of (also the lack of window). Very interesting theories as to how it got on this PCB in the first place.



    Might have to hold onto this little guy and not sack him for this project, I'm interested what others know about this sort of thing. Thanks so much for the sleuthing guys!
  • i2a2n2i2a2n2
    I'd be inclined to think it is also a OTP eprom
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