7
which match the five pins on the 3-500 triode. Insert the tube into the socket making sure that the
pins align with the socket contacts. If the tube pins and socket contacts are not aligned, the
amplifier will not function properly and damage to the tube may result. After you have properly
inserted the tube into its socket, connect the parasitic suppressor choke coming from the top of
the plate choke to the plate connector pin located on the top of the tube. The connector should
snugly slide over the plate connector pin.
LINE VOLTAGE SELECTION POWER POWER BLOCK WIRING
Before performing any of the following installation procedures, make sure that the amplifier
has not been plugged into the AC supply line.
Refer to the four Power Block Wiring Diagrams while reading this section. Locate the Line Voltage
Power Block. It is located inside the just above the AC line Cord, and it contails 6 screw
connection termials. It also has black and white leads connected to it.
120 VAC:
Two wire jumpers (J1 & J2) are connected to terminals. J1 is connected to terminals
1 & 4. J2 is connected to terminals 2 & 5. If there is a white wire connected to left side of terminal
6, remove it an connect it to left side of terminal 5. Also, if there is a black wire connected to the
left side of terminal 3, remove it and connect it to the left side of terminal 2. Remove the small
black wire connected to the right side of terminal 3 and connect it to the right side of terminal 2.
Make sure all screws are tightened.
240 VAC:
One wire jumper (J1) is connected to terminals. If a second Jumper was previously
connected to the terminal block, you make discard it. J1 is connected to terminals 2 & 4. If there
is a white wire connected to left side of terminal 6, remove it an connect it to left side of terminal
5. Also, if there is a black wire connected to the left side of terminal 3, remove it and connect it
to the left side of terminal 2. Remove the small black wire connected to the right side of terminal
3 and connect it to the right side of terminal 2. Make sure all screws are tightened.
You are now ready to replace the amplifier's top cover.
The hot air exhaust holes should be
located on the top left and the cooling air entry holes should be on the right side.
Align the
mounting holes with the corresponding threaded inserts located on the chassis. You may also
need to use an alignment tool such as an awl. You may need to lightly tap the top cover into place
with your hand. The left and right sides of the top cover may need to be pushed inward as you
place the mounting screws into place. Replace the nine 6-32 x 3/8 mounting screws and washers.
Partially tighten each screw. When all nine screws have bee inserted, tighten all the screws.
Double check to make sure that the cooling air entry holes are on the right side , and the
hot exhaust air exit holes are located on the top left directly over the tube.
RESHIPMENT INSTRUCTIONS
Use the original packaging if it is necessary to return the amplifier, transformer, or tube to QRO
for servicing. The original shipping carton and the interior corner pads are designed to provide
the necessary support for safe shipment or reshipment. If the original carton along with the
internal packaging is not available, contact the factory and a new carton will be shipped to you
at a nominal cost. Always insure the package for the full replacement value and ship via UPS
ground service.
QRO Technologies, Inc. will not be responsible for any damage or loss
