Taito F3 Repair Logs
Symptom: Makes a loud noise
Replaced bad fan and tested
Tip: Convert games to different regions
The F3 system uses keyed cartridge connectors for different regions. To change regions on the game requires either the modification of the connectors, removing the keys, or reprogramming of the EPROMs.
To reprogram the EPROMs, simply change the last byte of the last Program EPROM on the right: 01 = Japan, 02 = USA, and 03 = Europe
Tip: Making a multi-region cart
CAUTION: Be careful wiring the switch! If you miswire it you could create a dead short between +5v and ground which could damage the cartridge and/or game board. DO THIS AT YOUR OWN RISK.
Some carts look MUCH better in Japan region than they do in the US region: Puzzle Bobble 2 is an example of one. To change the region one must change the last byte of the right most EPROM so to make a dual region cart, simply use an EPROM that is 2x the size and copy/edit the code.
The Puzzle Bobble 2 cart uses a 27C020-12 EPROM. Read the right most EPROM into your programmer. Copy the code region from 00000 to 3FFFF and paste it into region 40000 to 7FFFF. Next edit the byte at 7FFFF and change it to 02 for the US region. Program it into a 27C040-12 EPROM and verify it. Next, mount a SPDT switch to the top case of the cartridge. Wire one outside contact to +5v and the other to ground. Take the EPROM, bend pin 31 out straight from the body of the chip and trim the skinny part of the leg off. Solder a wire from the uppermost address line which, in the case of the 27C040, is pin 31 to the center contact of the switch.
To run one region, flip the switch then power up the unit. To change regions, turn the game off then move the switch to the other position and power it back up.
DO NOT flip the switch while power is on. It could crash the game - but won't cause damage. You WILL need to reset the backup data when changing regions, just like you would if you switched carts on the F3 system.
Symptom: Missing Video RAM chip
Board was missing a surface mount IC and had attempted repair damage. Rebuilt 4 pulled pads, soldered in a replacement video RAM IC at location IC8, and soldered one jumper wire. Replaced dead cooling fan and tested.
Symptom: Up control doesn't work
Game does not register an up motion on the joystick. Checked the pin on the JAMMA edge and found it was not tied high, but was grounding properly when the stick was pushed up. Replaced a bad 390 ohm resistor pack at location RB17 and tested.