Modification of a MBC5 Cardridge ================================ Search for GB Color Games with save option. 64kbit or 256kbit will fit the needs. I took a cheap NBC Pro 99 cardridge (8Mbit ROM, 64kbit RAM). DISCONNECT THE BATTERY FIRST ! To exchange a 256kbit RAM is not necessary but recommended, because more and more new games are out there which use more than 256kbit RAM. To remove the RAM and ROM it is the best to use a special "hot air" SMD remove solder iron. If you do not have access to one, bend every single pin carefully up (with help of a needle) by heating it. Be careful and do not lift the pads ! The RAMs used here are standard devices, find the datasheets here: http://www.usa.samsungsemi.com/products/family/browse/sram.htm http://www.usa.samsungsemi.com/products/summary/powersram/KM681000E.htm http://www.usa.samsungsemi.com/products/newsummary/powersram/K6T0808C1D.htm http://www.hitachi.co.jp/Sicd/English/Products/memorye.htm Other suppliers also have these RAMs, the name of the types may differ from these above. Check datasheets for the same pinning. The Flash datasheet could be found here: http://developer.intel.com/design/flcomp/datashts/290606.htm As far as I know, there is only this Flash out there with this pinning, you can NOT use another ! Beside this, FLASH ID will differ and the progrmming software will not recognise the other device ! DO NOT TAKE THE TSSOP DEVICE, YOU WILL NOT BE ABLE TO SOLDER THE THIN PINS ! Bend the pins of the 1Mbit SRAM towards the case (see picture 1.). Nearly all pins will fit to the pads on the PCB, except the following: 1(NC), 2(A16), 28(A13), 29(WE#), 30(CS2), 31(A15), 32(VCC) Bend these straight (see picture 2.) then solder the IC to the pads. Pins 16 and 17 should touch the former pins 14 and 15. Pins 1, 2, 28, 29, 30, 31, 32 should not touch the PCB and should not be soldered at this time. Check if there is a connection on the PCB from the former RAM pin 1 to the MBC5 pin 28 (RAM A14). 256kbit cartridges should have these connection, 64kbit not. Next connect the open pins to the appropriate signal. The best is to use 0.2mm copper wire with varnish insulation (used in transformers). The insulation varnish can be easy removed by heating the wire with the solder iron and then put solder tin on it, as long as you can see that the solder tin burns the varnish away. Make the follwoing connections: RAM pin 1 not connected, not used 2 MBC pin 26 (RAM A16) ( 3 MBC pin 28 (RAM A14) see above, if there is a connection, leave this out) 28 MBC pin 29 (RAM A13) 29 MBC pin 30 (RAM WR#) 30 MM1134 pin 3 31 MBC pin 27 (RAM A15) 32 C3 nearby leads VCC, pick up from there That was the easy part ! Now the ROM is exchanged with a Flash device. You can take every device from 8Mbit uwards, but the Intel 32Mbit/64Mbit (28F320J5/28F640J5) device is preferred, because some programming software recognise this type. This articel describes the insertion of the 28F640J5 type in conjunction with the use of the BUNG ExChanger (V2) programmer to program the cartridge. OTHER COMBINATIONS ARE NOT TESTED ! Much soldering experience is recommended for this modification ! Flash datasheet could be found here: 28F320J5, 28F640J5 ROM pin view could be found here: 8Mbit ROM. The orientation on the PCB is like the RAM (cartridge connector points towards you, the MBC5 and the battery is on the upper side), pin 1 points to the left upper side. Connect a 0.2 mm copper wire (see above) to every pad and lead them to the right or left side for about 3 cm. Refer to picture ?, the datasheets and the table. ROM FLASH wire function connect Pin Pin to to 1 left NC 2 13 left A16 3 5 left A15 4 2 left A12 5 45 right A7 6 46 right A6 7 47 right A5 8 48 right A4 9 49 right A3 10 50 right A2 11 51 right A1 12 37 right A0 13 38 right D0 14 40 right D1 15 33 right D2 16 44 right GND 17 31 right D3 18 27 left D4 19 25 left D5 20 16 left D6 21 18 left D7 22 1 left CE# 23 53 right A10 24 21 left OE# 25 54 right A11 26 52 right A9 27 43 right A8 28 3 left A13 29 4 left A14 30 12 left A17 31 11 left A18 32 right VCC ------------------------------------------------ 7 CE1 GND 34 CE2 GND 28 VCCQ VCC 22 WE# cartridge pin 31 36 BYTE# GND 56 VPEN VCC, see text 29 GND GND, see text 44 GND GND 14 VCC VCC 6 A22 MBC pin 25 8 A21 MBC pin 22 9 A20 MBC pin 21 10 A19 MBC pin 20 55 RP# Reset#, cartridge pin 30 15 not used 17 not used 19 not used 20 not used 23 not used 24 not used 26 not used 30 not used 32 not used 35 not used 39 not used 41 not used 42 not used Put adhensive textil tape with the size of the ROM above the wires, so that the pads are covered from it. Bend all pins of the Flash straight, see picture ? 2.. Take some thicker wire (e.g. from resistor) and solder one on the lower end of C2 (VCC) pionting to right and another one at the lower left, 5mm above pin 32 (GND) to the GND plane pointing left (refer to picture). These are used as a base to fix the device. Solder them to pin 56 and 29 of the Flash. Now connect all wires to the appropriate signal. Use a ohm meter to find the right one, keep the lines short. Below the dashed line are additional connestions that have to be made to the Flash. Try to keep the VCC/GND (14, 28, 44) lines as short as possible. Thats it, now our cartridge must look like this one on the picture .... and should work! SOME OTHER PROGRAMMING HARDWARE MAY USE AN OTHER WRITE LINE THAN THE AUDIO (CARTRIDGE PIN 31). YOU MUST CHANGE THIS IN THAT CASE ! The BUNG programmer ALWAYS use the audio line (cartridge pin 31) to write the Flash device !