Turn the reciever on for a second or two and then off before the protect mode shows up on the monitor. Repeat this step about five times and check to see if the reciever does not go into protect mode. If it does go into protect mode try it again. Dont know if this is the proper way to fix the reciever but it worked for me. Good Luck
HK protection circuits are complicated.
They go into protect for overload, DC detect, and thermal runaway.
The protection circuit itself can also fail. It is impossible to diagnose over the internet, and testing must be done at the circuit level to trace the cause.
NOTE: There is one thing if you have not tried it, and that is:
1) Disconnect all connections - disconnect all speakers, components, etc.
2) Disconnect power for 5 minutes.
3) Reconnect ONLY the power, and see if it still goes into protection mode. If it does, the problem is INTERNAL. If not, the problems is likely one of speakers/wires/components.
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I have found cold solder to open resistors 4.7ohm 1w in these HK receivers.
Cold solder point. 99.9%
SOURCE: amp comes on and goes
Protection is usually a sign of overheating or something is wrong at the power amplifier's output.
Theory: Protection is a delay and sometimes an internal test to allow the electronics to stabilize during power up before they are allowed to interact with the speakers. The most common cause of it remaining ON is that a speaker cable pair is shorted. Some isolation is required...
1. Turn the Power OFF.
2. Disconnect each set of the speaker wires that are directly attached to the receiver. Mark them so you remember where each one went. pay special attention to which conductor is on "+" or "POS" and which is on "-", "COM" or "Ground". You may elect to disconnect them one pair at a time if your sytem is complex and you don't want to lose track of where things were.
Turn the Power ON. Is the "Protect" indication gone from the display?
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If YES, you have a shorted speaker wire or speaker. To isolate the specific cause:
1. Turn the Power OFF.
2. Attach ONE speaker wire pair at a time and test it by turning the Receiver ON. When the "Protect" light returns you have isolated at least one of the cause(s). Disconnect the defective speaker cable and continue isolation of all speaker cables. Visually examine the cable at both ends for frayed wires that could touch each other or contact metal on the receiver or other objects.
To isolate further within the cable/speaker pair - disconnect the speaker end of the cable on the failing path. Try another cable that you know works, or at least one that doesn't cause Protection to stay on.
If you're electrically savvy and have a Digital Volt/Ohm Meter you can troubleshoot the short(s) with it.
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If NO, there is probably an internal problem.
Is it solid or does it come on after the Receiver has been ON awhile.
It could be overheating.
Is the unit hot to the touch?
Is there a cooling device (fan)?
Is it stopped or clogged with dust?
Is there adequate ventilation around the unit for air to flow?
Clean any ventilation slots on the top and bottom of the unit.
Avoid stacking components that produce heat under an amplifier or receiver. Their heat rises. Also keep them away from other heat sources like like home heating vents and radiators.
Problem solid and NOT related to the speakers or heat: internal malfunction.
Let me know.
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Yes, same issue and it is driving me crazy. Is it too much load? or something else? I just hooked it up and about to take it back and try a more expensive unit.
same thing... tried cleaning it out with air and still nothing. Woindering if its a heat issue?
Same problem, has anyone resolved this issue. Amp has been working fine up until today.
Thanks,
dw
Bought the ds939 second hand. I bought it only to power a pair of infinity kappa 8 speakers . The combination sounds awesome until I take the volume to about 50%. In a few seconds it will shut down and go to protection mode. Are the speakers too much for the amp? thanks, Mike
same thing bro
As soon as I turn on the amp it goes into protect mode.it's not caused by speaker wires. My son was touching some buttons on the face of the amp and it went into protect mode
i have the same trouble with the receiver going straight to protect mode please let me know if anyone has figured it out thanks
I also have the HK 3480 receiver. It was working fine and then one day I pushed the power button, saw the decibel display briefly, received the "Protect" message on the display, and then everything shut down. I takes about four seconds for it to shut down. I've unplugged all connections on the back and still get the same error.
saw the decibel display briefly, received the "Protect" message on the display
2 - 3 seconds after i turn the power on the decibel displays briefly the "Protect" message on the display and then it just shuts down.
by the way my model is TX - DS787
I Have a str de 697 that goes into protect after 5 seconds it is totally dosconnected from the rest of the stereo and pluged into the wall by itself and still does it
ya i think the amount of dust is the problem .. thanks..
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