Specifications

2.5.1 Description
The power supply provides the following voltages:
5.10V @ 6A
12V @ 1A
-12V @ 1A
42V @ 12A
85V @ 4A
The major components of the power supply are:
The Power Supply Filter (SPSX)
The Power Supply Master (SPSM)
The Power Supply Regulator (SPSR)
The Power Supply Discharge (SPSD)
There are also two chassis mounted capacitors distributed in the printer.
2.5.2 Shuttle Power Supply Filter (SPSX)
The SPSX board is located in the ac switch box at the rear of the printer
near the power ON/OFF switch. It provides the following functions:
• High frequency filtering.
• Transient voltage limiting on the ac input line.
• Conversion of the ac input to full wave rectified dc, by using an
external bridge rectifier mounted inside the ac switch box.
2.5.3 Shuttle Power Supply Master (SPSM)
The SPSM board is located in the power module on the left side of the
printer. It converts incoming full wave rectified voltage to 85V from the
SPSR for the input to the SPSR board.
The SPSM is protected, so it will not be damaged if the output is shorted.
Since the SPSM has a high current usage, it has forced air cooling.
If the 12V bus exceeds 16.5 V, an internal crowbar will operate to bring
the bus down to 3 V. When this happens, a fuse will blow (F1, or F2, or
F3, or F4, or F5).
The SPSM also contains an active bleed-down circuit. It is a non-linear
current dumping circuit across the 85V bus. In operation it removes the
energy remaining in all the buses after the printer has been turned OFF.
2–14 THEORY OF OPERATION