Einleitung
This amplifier has a weak connection of the input jack to the board. If the nut comes loose, or the cord connection is bent, the tabs that are soldered to the board may break free taking the PCB tabs off the board. This guide will show you the repair.
Werkzeuge
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Use a Phillips #0 screwdriver to remove the four 21.7mm screws holding the back panel to the frame.
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If the power cord plugs into this panel, you will need to do the "modified" steps
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Once the screws are out, use a plastic opening tool or spudger to pry the top of the back panel open. There may be some resistance, but it will eventually pry loose.
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Once the top is separated, use your hand to remove the back panel from the unit.
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Modification: If the back panel has the power cord receptacle attached, you will need to mark the colors of the wires, and remove the wires at the receptacle by pulling them from the tabs.
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There will be two black wires connecting the top mounting bracket to the reverb box at the bottom of the unit. Label the wires to prevent crossing upon re-installation, then unplug the wires from the reverb box.
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Modification: If there are not two black wires and a reverb box, there will be two twisted pair of wires attached to the board coming from a spring reverb mechanism on the right side of the case. You will need to spread out the clip and pull these wire connectors from the board. Be sure to record which color goes where!
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Label and unplug the two red wires connecting the mounting bracket to the speaker by pulling them off the nodes.
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Modification: These may be a white and black wire.
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Use a Phillips #1 screwdriver to unscrew the four 36.4 mm screws holding the mounting bracket to the top of the amp.
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Modification: There may only be two screws (one on each side). If so, you will need to remove two screws from the inside that attach the mounting bracket to the speaker board.
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Pull the mounting bracket free from the frame. It may be wedged in very snug, in which case, use a plastic opening tool/spudger to pry it loose from the front.
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Modification: as mentioned in the last step, you may need to first remove two screws from the bottom of the mounting bracket that hold it to the speaker board.
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Mark, make note of, or remember the arrangement of the wires to the power switch.
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Remove the four female disconnected terminals from the switch terminals.
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You will need to pull off the knobs covering the shafts of 7 pots. Then remove the retaining nuts that fasten these pots to the faceplate.
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Now remove the retaining nuts on the head phones jack and input jack
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Now remove the screw fastening the Aux In RCA jacks
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Modification: You may also need to remove two screws on the bottom of the mounting bracket that attach the heat sink (a metal rectangular piece attached to the pc board)
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Here's the problem with this one. The soldered tab from the input jack ha lifted off the pad and damaged the trace above it. When I slightly wiggle the input jack, the lose tab moves on the board.
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I scraped the pad between the two tabs that share a connection, I also scraped the trace to past where it had lifted up. Scrape carefully to expose bright copper, but don't cut through the trace or pad
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I soldered a bridge between these two tabs that share a connection and across the part of the trace I shaved. I also added a jumper to back up that trace.
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To reassemble your device, follow these instructions in reverse order.