User Guide
MULTI CHANNEL AV RECEIVERSTR-DH750/STR-
DH550
PROTECTOR
The receiver will automatically turn off after a few seconds. Check the followings:
There may be an electrical surge or power failure. Unplug the AC power cord (mains lead) and
then plug in the cord again after 30 minutes.
The receiver is covered and the ventilation holes are blocked. Remove the object covering the
ventilation holes of the receiver.
The impedance of the connected speakers is below the rated impedance range indicated on the
back panel of the receiver. Reduce the volume level.
Unplug the AC power cord (mains lead) and let the receiver cool down for 30 minutes while
performing the following troubleshooting:
o Disconnect all of the speakers and subwoofer.
o Check that the speaker wires are tightly twisted on both ends.
o Connect the front speaker first, increase the volume level and operate the receiver for
at least 30 minutes until it completely warms up. Then, connect each additional speaker
one by one and test each additional speaker until you detect which speaker is causing
the protection error.
After checking the above items and fixing any problems, plug in the AC power cord (mains lead)
and turn on the receiver. If the problem persists, consult your nearest Sony dealer.
USB FAIL
An over-current from the (USB) port was detected. The receiver will automatically turn
off after a few seconds. Check the iPhone/iPod or USB device, then unplug it and turn on the
power again.
List of messages after Auto Calibration measurements
Error 30:
Headphones are connected to the PHONES jack on the receiver. Remove the headphones and
perform the Auto Calibration again.
Error 31:
Front speakers are not selected properly. Select the front speakers using SPEAKERS and perform
the Auto Calibration again. For details on selecting the front speakers, see “Selecting the front
speakers (for STR-DH750 only).”








