Amada Miyachi Unitek STA-100A, Operation Manual, Page: 71 / 154

CHAPTER 5: MAINTENANCE
STA SERIES AC CONTROLS
990-351 5-7
Power Transformer T1
1 Disconnect the transformer cable connector from AC Timer Main Board connector J17.
2 While supporting the transformer with one hand, remove the two screws and lock washers.
3 Install re-install the transformer by supporting it with one hand while attaching it to the side of
the card cage with two screws and lock washers.
4 Reconnect the transformer cable connector to AC Timer Main Board connector J17.
Power Transformer T2
1 Disconnect the transformer cable connector from AC Timer Main Board connector J19.
2 While supporting the transformer with one hand, remove the two screws and internal tooth lock
washers.
3 Install or re-install the transformer by supporting it with one hand while attaching it to the side
of the card cage with the two screws and internal tooth lock washers.
4 Reconnect the transformer cable connector to AC Timer Main Board connector J19.
Valve Transformer, T3
1 Remove the following four wires from the transformer terminals: H1 (yellow), H4 (orange and
gray), XF (red), and X2 (black).
2 While supporting the transformer, remove the four 10-32 x 3/8 Phillips head screws, #10 split
lock washers, and #10 flat washers that secure the transformer to the Control and remove it.
3 Install or re-install the transformer with four 10-32 x 3/8 Phillips head screws, #10 split lock
washers, and #10 flat washers.
NOTE: If you are installing a new transformer, be sure to reconnect the jumper(s) in the same
configuration as previously connected. See the
Wiring Diagram
on page 5-4 for specific
connections for different voltage inputs.
4 Connect the following wires to the indicated terminals and tighten the screws: yellow to H1,
orange and gray to H4, red to XF, and black to X2. Be sure to install the proper fuse, as shown
in
Section V, Parts List .
Surge Resistors
1 To replace a surge resistor assembly, disconnect the violet wire from the SCR and the gray wire
from Valve Transformer terminal H4.
2 Remove the four screws and lock washers that attach the surge resistor assembly to the Control.
3 Install or re-install the surge resistor assembly by attaching the assembly to the Control with
four screws and lock washers.
4 Reconnect the violet wire to the SCR and the gray wire to Valve Transformer terminal H4.
Snubber