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each point.
5. Reverse the AC plug in the AC outlet and repeat each of the above
measurements.
6. The potential at any point should not exceed 0.75 volts RMS. A
leakage current tester (Simpson Model 229 or equivalent) may be
used to make the hot checks, leakage current must not exceed 1/2
milliamp. In case a measurement is outside of the limits specified,
there is a possibility of a shock hazard, and the equipment should
be repaired and rechecked before it is returned to the customer.
2. Handling the Lead-free Solder
2.1. About lead free solder (PbF)
Distinction of PbF P.C.B. :
P.C.B.s (manufactured) using lead free solder will have a PbF stamp on the P.C.B.
Caution:
- Pb free solder has a higher melting point that standard solder;
Typically the melting point is 50 - 70°F (30 - 40°C) higher. / Please
use a high temperature soldering iron. In case of the soldering iron
with temperature control, please set it to 700 ± 20°F (370 ± 10°C).
- Pb free solder will tend to splash when heated too high (about
1100°F/600°C).
- When soldering or unsoldering, please completely remove all of the
solder on the pins or solder area, and be sure to heat the soldering
points with the Pb free solder until it melts enough.
3. Before Repair and Adjustment
Disconnect AC power, discharge Power Supply Capacitors C546, C547, C548, C549 through a 10
, 1 W resistor to ground.
DO NOT SHORT-CIRCUIT DIRECTLY (with a screwdriver blade, for instance), as this may destroy
solid state devices.
After repairs are completed, restore power gradually using a variac, to avoid overcurrent.
Current consumption at AC 230-240V, 50Hz in NO SIGNAL mode should be ~500 mA .
4. Protection Circuitry
The protection circuitry may have operated if either of the following conditions are noticed:
- No sound is heard when the power is turned on.
- Sound stops during a performance.
The function of this circuitry is to prevent circuitry damage if, for example, the positive and
negative speaker connection wires are
"shorted", or if speaker systems with an impedance less than the indicated rated impedance of
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