Hafler JF2000 Owner's Manual page 13

No LED
Turns Red
(overheats)
Rapidly
Channel Status LEDs
(Two Left LEDs)
This is an indication that no power is reaching the amplifier.
Possible reasons
1) Amplifier not securely plugged in.
2) Power source (socket) failed (AC line fuse blown,
wiring open, etc.)
3) Internal amplifier fuse blown. Fuse replacement
should only be attempted by a qualified technician.
1) Rear cooling channels blocked. Clear the area behind
the amp.
2) No fresh air ventilation (rear air intake and output feeding
each other). Provide a source of fresh air (not heated air)
for the inlets at the sides.
3) Excessive loading. If the amplifier is run into less than a
4-Ohm speaker load per channel, or is bridged into less
than 8-Ohms, the amplifier may not be able to produce
continuous high output levels without overheating. Re-
duce the loading by increasing load impedance.
4) Fan is jammed or has failed. Clear the obstruction or
replace the fan.
5) There may have been an internal malfunction. Send amp
to the factory or a qualified technician for repair.
The channel status LEDs can show three indications:
OFF indicates no signal or a signal level under about 200
Milliwatts (a very quiet level with most speakers).
GREEN indicates a signal over about 200 Milliwatts and very
low distortion (under 0.5%) for most conditions); that is,
normal operation.
RED indicates distortion in the output amplifier
reason: blown speaker fuse, shorted speakers, excessive
speaker load, or any other reason.
include:
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