Commodore 1541 - Electrical Theory and Frame Operation

2-3. Electrical Theory (Refer to Figures 2-5 and 2-6)
2-3-1. Frame Electrical Theory
AC LINE
POWER
SWITCH
FUSE
X-FMR
9V RMS
16V RMS
Figure 2-5. Frame Assembly, Block Diagram.
The electrical function of the frame assembly is to condition
and convert the AC line voltage before applying it to the
power supply on the disk controller PC Board.
The AC line voltage enters the disk drive at J9, which is
both a connector and an RFI filter. After passing through
the filter, the AC voltage is applied to the SPST power
switch, Sl. The output of the power switch is applied to Fl,
which provides ever-current protection. Fl is a !A, 250V
Slow Blow fuse. The output of Fl is fed to the transformer,
Tl. Tl steps down the AC line voltage into +9 Vrms and +16
Vrms. Both of these outputs have their own secondary
windings and are isolated from each other.
It should be noted that the AC return line for the primary of
Tl may be connected to either tap on the primary winding.
The black tap must be connected for use with Disk Controller
P.C.Bd. 1540001-xx (long board version typical of
VIC-1541(1540)). The red tap must be connected for use with
Disk Controller P.C.Bd. 1540048-xx (short board version
typical of 1541). Either Board may be used for replacement
of the other provided the correct tap of Tl is used. See
Section 3 for AC power configuration.
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