Modifying any ROM+MBC1+RAM cart to be a C3 cart:

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1. Cut out old ROM - I use a sharp X-acto and cut the legs off of

  the rom right at the chip. It then is very easy to remove the

  remaining legs with a fine-tipped soldering iron. Another way

  which saves the ROM but takes longer is to lift each leg

  individually with an X-acto or any sharp, pointed device after

  heating each leg with a soldering iron.



   It is VERY easy to damage the PC board rom pads so keep that

  in mind if you use other techniques to remove the ROM.



2. Program the flash eprom with GB Basic if possible - This will

  let you test the cart immediately upon completion of your

  cart soldering work.



3. Install 4mbit flash eprom - I do this by first cleaning ROM

  PC board pads if there is too much solder with solder wick.

  I then place the flash "as is" on the PC board and solder it in

  place with the middle pin on each side where the old ROM was

  located. With two pins of the flash soldered in place, I use

  an X-acto (or sharp, pointed knife) to carefully bend some pins

  on the sides to reach old ROM pads. I then solder all of the

  pins on each side to pads located close by.



4. Solder top & bottom rows of PLCC to board - Since very few

  of the top & bottom pins of the PLCC packaged flash will

  reach the remaining ROM pads on the PC board, with a sharp

  blade I very carefully pry each pin up 90 degrees and then

  use needle nose pliers to mold them in the general direction

  I want them to go.



   You can do this no problem with new flash chips if you are

  careful. This will not work with older, used flash chips that

  have been inserted & removed numerous times. You can only bend

  integrated circuit pins so many times before they will break

  off.



   Use wire wrap wire to solder connect pins that can't reach pads.



5. Install 47k pull up resistor - The wire that goes from

  one end of this resistor connects to pin 31 of the cart

  connector. BEFORE soldering to this cart connector pin place

  some form of tape covering 75% or more of this gold pin. (This

  is to prevent solder from wicking down the whole pin.)



   Remove tape from pin when soldering is complete.



6. Test the cart on your GB - If you programmed the flash with

  GB Basic before installing then it should show this upon

  powering up your GB. If not, you have a wiring problem.