WhitakerAudio J C Whitaker 20 W Stereo Audio Amplifier, Manual

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81
20 W Stereo Audio Amplifier
– Find SW202 – SPST toggle switch . Set this device aside. It will be used later. This device
is installed on the front panel.
– Find SW203 – High temp thermostat . Set this device aside. It will be installed later.
– Install the sockets for the five plug-in relays. Solder in place.
– Install RYL201, RYL203, RYL205 – DPDT, 10A, 24 V dc . Make certain to install the 24
V dc relays in the proper sockets. Refer to the legends printed on the PWB.
– Install RYL202, RYL204 – DPDT, 10 A, 120 V ac, relay . Make certain to install the 120
V ac relays in the proper sockets. Refer to the legends printed on the PWB.
Important : If the 120 V ac relays and 24 V dc relays are not in their proper positions,
component damage will result.
Examine the fuse holder. Some devices have a small plastic pin protruding from the mounting
side. This pin must be clipped off or the holder will not mount flat against the PWB.
– Install the fuse holder using the #4 hardware provided. Use short bare connecting wires
from the terminals to the pads on the PWB. Solder in place. Tighten the set screw (do not
over-tighten).
A method that works well for the above step is to first mount the fuse block with the hardware
finger-tight. Then feed the bare wire up from the foil side of the board and affix it to the terminal.
Solder and then repeat for the other side of the component. Finally, tighten the mounting screw.
– Find the 0.5 A fuse (F201). Install in the socket.
– Install the power transformer – Transformer, PC mount, 115 V ac primary, 25 V ac
secondary . Orient the device so pin #1 lines up with the square mounting pad. Solder in
place.
– Find the 2.5-inch long mounting standoffs. Set aside for now. They will be installed later.
If desired, a single light coat of acrylic conformal coating (MG Chemicals #419C-340G) may
be applied to the foil side of the board. In addition, brush-applied acrylic conformal coating (MG
Chemicals #419C-55ML) may be applied the B+Sense terminal on the preamplifier power supply
PWB. Using the brush provided, apply a light coat at the base of the quick-disconnect terminal
post so that it covers the immediate vicinity of the PWB pad.