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楼主 |
发表于 2013-12-28 11:02
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Bias
Remove the B + fuse F2. This fuse is in the line from the ’ +’
capacitor terminal to hole #3 on the board. Connect an
ammeter’s ' + ' !ead to the fuse clip nearest the large filter
capacitors. Connect the’ -’ lead to the other side of the fuse clip.
Avoid intermittent connections, and do not short the leads
together. Turn the amplifier on, and if possible adjust the line
voltage to 120 volts. Adjust P2, near the middle of the board, to
275 mA. Turn the amplifier off, and when the current drops to
zero, then remove the ammeter and replace the fuse.
Offset
A DC voltmeter capable of resolving 10 mV variations is
needed. Connect it to the output terminals of the selected channel,
and adjust Pl, near the top of the board, to zero volts, + 10
mV. A small correction of the control will produce a large initial
change, which will settle down in a second. Repeat these small
changes to achieve zero volts. |
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