Mesa/Boogie Subway WD-800 Owner's Manual page 17

SYMPTOM:
Protect LED turns on:
1. Disconnect all cables except power cable, if the amp is no longer in protect, try plugging in just the speaker cable. If the amp
goes immediately into protect, one possible cause is a defective or damaged crossover that is presenting an illegal load to
the simplifier and the protection circuit is working correctly. (try a known good speaker cabinet from another manufacturer to
rule this possibility out. If the amp works correctly with another speaker cabinet, call customer service for assistance. This is
more common with "do it yourself" speaker projects with incorrectly designed crossovers. ALL amps with PWM carriers are
sensitive to stored reactive energy is defective crossover tank circuits.)
2. Protect circuit shuts down amp while playing at low to moderate volumes (possible shorted speaker cable, try known good
speaker cable)
3. Protect circuit shuts down amp at moderate to high volumes. Verify that total load to the amplifier has not fallen below 4 ohms
(or 2 ohms on models that support 2 ohms with the impedance selector switch set to 2 ohms). (possible causes are incorrect
pairing of multiple speaker cabinets, incorrectly labeled speaker cabinets that were repaired or modified without relabeling,
defective driver that has shorted voice coil turns as voice coil warms up.)
4. Power source voltage falling dangerously low due to improper wiring or extension cable that is too long for it's wire size. (trig-
gering the amp's under-voltage protection), or from dangerously high power source voltage (triggering the amp's over-voltage
protection) (correct problems as needed with the help of a qualified electrician)
SYMPTOM:
No (or slow) USB charging of connected device:
1. Is this an Apple device? There are several program controlled charge rates available for Apple products, varying from 100mA
all the way up to 2.1A. The charge port will support the 500mA standard, which will charge the larger devices more slowly
than the bigger dedicated chargers.
2. Is this an Apple i-Pad or other large tablet? When operating an iPad or tablet, the current draw of the screen alone will be
close to 500mA so the charging rate will be very low. Operating with a charged battery and also connected to the charge port
on the amp will greatly extend the battery life under use however.
3. Is this an Android phone that Qualcom QC enabled? This charger does not support QC, and will charge at the slower 500mA
rate if the device software allows it.
4. Does your device use a USB-C connector? While it won't charge at the higher rate's supported by this standard, it should be
backwards compatible with the 500mA standard.
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