TMFX Power Supply Notes

Photos of a 1994 TMFX-C902 Power Supply card that has a failed 12v output.

Card Overview, base is a large heatsink with a fan under it. High Voltage input is on the left.
closeup of high power capacitor
Adjacent Nichicon Cap that appears to have been replaced.
Output area. CP4 and D23 are part of the 12v circuit. The green connector goes to the S (sewing) and X/Y cards. The board is clearly designed to be serviced or it wouldn’t have test points. Unfortunately, Tajima refuses to share schematics to keep their machines running. They also won’t provide parts or service for it.
Another shot of the output side. Nitsuko caps. The grey/black cap is a Kemet with a date code of 3/12 on it suggestion prior repair. It’s also seated differently from the Nitsuko’s.
Another photo of the output area. There are 3 transformers but I’m not sure what each does. One probably is for the 80VAC legs, and then if I had to guess one is for the 26vdc leg and the other is a 12vdc/5vdc.

Another intermediate shot of the same area. All the power transistors are at the bottom on a dedicated aluminum heatsink. Overall it’s a well designed circuit. It’s just difficult to service without a schematic.

Overview of front of board. High Voltage to left. Low Voltage to the right.
Overview of Low Voltage Side.
Overview of High Voltage Side
Close up of heatsink (bottom) of High Voltage Side.
Another closeup to see the FET/IGBT/BJT’s
Close up of the bottom of the low voltage side.
Back of Board. Low voltage on left, High voltage on right. Pigtailed connectors are 120v input and 80vac/120vac output to servo cards.
Upper Left Back closeup. Prior repair/damage evident on pins. They are cut flush unlike the rest which looks to have been wave soldered. 8 pin area in upper left contains the 12v line.
Lower Left, back of board.
Center back of board.
Center bottom of back of board.
Upper right of back of board.