Hafler DH-110 - Manual (Page 15)

IF A PROBLEM ARISES
If neither LED lights when you first turn on the power
switch, turn the unit off immediately. Check the fuse.
Check the polarity of the LEDs. Check the power
transformer wiring for proper connections for your line
voltage. Look for a short caused by a stray strand of wire,
or for a solder splash on the circuit board. A print of the
circuit pattern in this manual enables you to check out a
doubtful connection which might include a solder bridge.
If there is no audio output, is the monitor switch OFF? Is
the EPL switch OUT? Is the wiring of the phone jack cor-
rect? Are the plugs seated properly on the flat ribbon
cables-not offset by one pin? Is the Phono pushbutton
switch in the correct position? Check the PC-12 for a solder
splash between the circuit paths. A sharp knife can correct
that.
If there is noticeable hum; turn off the unit and reverse
the line cord. Make sure the preamp is not too close to the
power amplifier (or that the turntable is not too close,
either). Check for a defective connecting cable, or turn-
table ground wire. Inside the preamp, the screws for the
thumb nut ground connections must be tight, both to the
PC-12 board, where the lockwasher under the screw head
contacts the circuit ground, and to the back panel, where
the lockwasher must break through the paint to the metal.
Also, the PC-14 rear bracket mounting screw near the
power transformer must be tight for a good ground con-
tact.
A spare 1/10 ampere slo-blo fuse is supplied with the kit.
A larger value fuse will not provide protection in the event
of a fault. If the replacement fuse blows, the unit should be
returned to the factory for competent service.
AC LINE CONNECTIONS FOR OVERSEAS USE
The power transformer supplied with the DH-110 has
dual tapped primary windings. By arranging these two
windings in various series-parallel combinations, line vol-
tages of 100,120,200,220 and 240 volt 50/60 Hz lines can be
accommodated.
The diagrams below show the connections for altema-
tives to the 120 volt connections shown on the pictorial
diagram. When connected for 200-240 volt lines, the line
fuse should be changed to l/16 ampere (60 mA) slo-blo.
2 4 0 V
J o
B L A C K
15