Fuse Ratings; Power Supply - SoundCraft Series 200 User Manual

FUSE RATINGS
220-240 volts AC the fuse should be 1.6 amps 10mm ANTI-SURGE.
100-120 volts AC the fuse should be 3.15 amps 20mm ANTI-SURGE.
BEFORE SWITCHING ON ALWAYS CHECK THAT THE VOLTAGE
SELECTOR IS SET CORRECTLY AND THAT THE FUSE IS CORRECT.
POWER SUPPLY
The Series 200 power supply provides the following regulated supply
rails;
1) ± 1 7 volts Audio
2) + 48 volts Phantom Power
If a power supply fauit is suspected, first ensure that it really is the
P.S.U. which is at fault, and not a short circuit in the console. This
can be checked by disconnecting the P.S.U. from the console, and
measuring the voltage at the connector. A load across the supply
should be provided, to simulate the normal load conditions imposed
by the console.
A 10 ohm, 20 watt resistor should be connected across each of the
audio rails. The Phantom power supply can be loaded with a 2.2K
ohm, 1 watt resistor.
The ripple and noise value of the various supply rails can now be
measured, using a millivoltmeter or an oscilloscope.
If a fault is found to exist in the P.S.U. disconnect the mains supply
and remove the cover. Check visually for any obvious problems, such
as blown fuse, burnt components, etc. If nothing obvious is observed,
reconnect the mains, and measure the voltages across the various
electrolytic smoothing capacitors, which should be as follows:-
Audio Supply C1 = + 2 6 volts
C2 = - 26 volts
Phantom Supply C12 = + 5 9 volts
Differences of ± 1 0 % are acceptable, due to variations in the
incoming mains voltage. If satisfactory, the problem lies in the
regulator section. If not however, check the bridge rectifier,
smoothing capacitor and transformer for failure.
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