Protect Light Flashing.
I too have one of these with the same problem,the unit is only 3 years old . I too did the troubleshoot check on both AVR and speakers but still the same .
I was sent a sevice manual by Denon and as a result of a quick study of the circuit diagram , I tried diconnecting the jumper link to the processor which is labelled 'Protect'. The effect of this was that when the unit is turned on , the display is now visible as normal , but no sound from the speakers .
It seems that the main processor requires a very small voltage from the output of the power transisitors to trigger the main processor to operate the speaker relay circuitry , but when there is an overvoltage ( whether of an intensity harmful to speakers or not) , the 'protect' circuit is triggered and remains so.
Can anyone offer some further assistance ?
Hi Techman, Thanks for the suggestion . I think what I did confirms that the main processor is working fine . When I checked the speaker outs with a MM before I cut the protect link wire , I had what appeared to be a slight low voltage leakage on the centre speaker with all others being stable . Yes I have a PDF of the sevice manual , which I can send you if I can have an email address to send it to. Cheers MalcolmHi Techman,
Thanks for the suggestion . I think what I did confirms that the main processor is working fine . When I checked the speaker outs with a MM before I cut the protect link wire , I had what appeared to be a slight low voltage leakage on the centre speaker with all others being stable .
Yes I have a PDF of the sevice manual , which I can send you if I can have an email address to send it to.
Cheers
Malcolm
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3,130 Answers
Re: Protection Light Flashing
You will need to measure the output transistors as well as the driver transistors or IC's for shorts, as it is a DC voltage that will trigger this protection circuit. If you have a PDF of this service manual, I would like to take a look at it and to tell you what to check.
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Disconnect all speaker wires from the unit and turn it back on, if it stays on, turn up the volume, if it does not go into protection, you have a speaker problem. If it does go into protection, it's less expensive to replace the unit than to repair. This unit is 9 model years old and was roughly 200-250 new. Any repair will be at least 100-150 and not worth the investment vs. return. If you look at new receivers, take a look at Yamaha RX-V series. Easy to use and very well built. Hope your current receiver is ok though!
If no Protection is displayed, turn off and connect one spkr at a time and test until you find the one that causes a problem, then try another spkr in the place of the one causing the short. if it still shorts, take the good spkr directly to the receiver with a short piece of spkr wire and test in the bad location. if it works then, replace the spkr wire, if it doesn't you've found your problem. Audio output chip. This is a very common problem and is repairable, yet the labor is what cost the most.
Hope this helps.
Protect mode will kicking whenever a fault is detected.
Causes that can start protect mode are:
Electrostatic harges on internal circuits.
Leave the unit unplugged for power for one hour or so, this will allow discharge.
Bad speaker wiring. Check speaker wiring, try unplugging and plugging back, or start after removing one speaker at the time.
Internal fault. Internal
fault is the natural cause for protect mode. If all the above did not
work, then the problem is a blown component or an internal fault. In
this case the unit must be taken apart , tested and repaired by an
experienced person. If the unit is less than one year old, or if you
want to get service, call Sony at the phone number listed on the
product documentation.
Protect mode will kick in whenever a fault is detected.
You get the unit not powering up, and sometimes you hear a clicking
noise, that is the protection switch that keeps shutting down the unit.
Causes that can start protect mode are:
Electrostatic harges on internal circuits.
Leave the unit unplugged for power for one hour or so, this will allow discharge.
Bad speaker wiring.
Check speaker wiring, try unplugging and plugging back, or start after removing one speaker at the time.
Internal fault.
Internal
fault is the natural cause for protect mode. If all the above did not
work, then the problem is a blown component or an internal fault. In
this case the unit must be taken apart , tested and repaired by an
experienced person.
If the unit is less than one year old, or if you
want to get service, call Sony at the phone number listed on the
product documentation.
Try first leaving the TV power cord unplugged for some times, let say one hour or so.
Also
ensure that the fault is not coming from a faulty receiver box sending
bad signal, check if you get same problem with no receiver box
or dvd connected.
If that does not work, and you keep having a flashing
led on front of the TV, and tv turning off by itself after a while,
that indicates a fault condition.
The flashing light indicates a diagnostic state called protection.
When the TV goes on protection there are only two possible reasons.
1The
internal circuits are jammed because of electrostatic
charges accumulating on capacitors, or because of a wrong voltage read
by the main chip on your monitor controller board. this started the
protection circuit.
2 The protection circuit detected a wrong
voltage or abroken contact, identified an internal fault and kicked in
, startingthe flashing light.
If you are in situation one, then theTV will reset just unplugging power cord for one or two hours,sometimes even minutes.
If you are in situation 2 , then there is an internal fault.
Common faults
that can occur are a blown capacitor on power board, a
convergence IC has blown, or a fault on Digital board.
Check also
the video cable or any external connection cable, if the cable is shorting, or the connector is bad, you
can get same flashing state because of the video cable.
If under warranty contact the manufacturer ringing the number on the user manual
If you want to repair at your own expenses, just locate any good qualified repairer.
Protect mode will kick in whenever a fault is detected.
You get the unit not powering up, and sometimes you hear a clicking
noise, that is the protection switch that keeps shutting down the unit.
Causes that can start protect mode are:
Electrostatic harges on internal circuits.
Leave the unit unplugged for power for one hour or so, this will allow discharge.
Bad speaker wiring.
Check speaker wiring, try unplugging and plugging back, or start after removing one speaker at the time.
Internal fault.
Internal
fault is the natural cause for protect mode. If all the above did not
work, then the problem is a blown component or an internal fault. In
this case the unit must be taken apart , tested and repaired by an
experienced person.
If the unit is less than one year old, or if you
want to get service, call Sony at the phone number listed on the
product documentation.
Protect mode will kick in whenever a fault is detected.
You get the unit not powering up, and sometimes you hear a clicking
noise, that is the protection switch that keeps shutting down the unit.
Causes that can start protect mode are:
Electrostatic harges on internal circuits.
Leave the unit unplugged for power for one hour or so, this will allow discharge.
Bad speaker wiring.
Check speaker wiring, try unplugging and plugging back, or start after removing one speaker at the time.
Internal fault.
Internal
fault is the natural cause for protect mode. If all the above did not
work, then the problem is a blown component or an internal fault. In
this case the unit must be taken apart , tested and repaired by an
experienced person.
If the unit is less than one year old, or if you
want to get service, call Sony at the phone number listed on the
product documentation.
Protect mode will kick in whenever a fault is detected.
You get the unit not powering up, and sometimes you hear a clicking noise, that is the protection switch that keeps shutting down the unit.
Causes that can start protect mode are:
Electrostatic harges on internal circuits.
Leave the unit unplugged for power for one hour or so, this will allow discharge.
Bad speaker wiring. Check speaker wiring, try unplugging and plugging back, or start after removing one speaker at the time.
Internal fault. Internal
fault is the natural cause for protect mode. If all the above did not
work, then the problem is a blown component or an internal fault. In
this case the unit must be taken apart , tested and repaired by an
experienced person. If the unit is less than one year old, or if you
want to get service, call Sony at the phone number listed on the
product documentation.
Protect mode will kicking whenever a fault is detected.
Causes that can start protect mode are:
Electrostatic harges on internal circuits.
Leave the unit unplugged for power for one hour or so, this will allow discharge.
Bad speaker wiring. Check speaker wiring, try unplugging and plugging back, or start after removing one speaker at the time.
Internal fault. Internal
fault is the natural cause for protect mode. If all the above did not
work, then the problem is a blown component or an internal fault. In
this case the unit must be taken apart , tested and repaired by an
experienced person. If the unit is less than one year old, or if you
want to get service, call Sony at the phone number listed on the
product documentation.
That sounds like the transmitter is shorted or faulty. Protection is a diagnostic mode that will prevent the unit from starting because of a fault. Below a little essay on protection mode, but in your case you should simply replace the transmitter. Call the phone number listed on the owner documentation to get a replacement.
Protect mode will kicking whenever a fault is detected.
Causes that can start protect mode are:
Electrostatic harges on internal circuits.
Leave the unit unplugged for power for one hour or so, this will allow discharge.
Bad speaker wiring. Check speaker wiring, try unplugging and plugging back, or start after removing one speaker at the time.
Internal fault. Internal
fault is the natural cause for protect mode. If all the above did not
work, then the problem is a blown component or an internal fault. In
this case the unit must be taken apart , tested and repaired by an
experienced person. If the unit is less than one year old, or if you
want to get service, call Sony at the phone number listed on the
product documentation.
Protet mode is a special diagnostic mode that starts when a fault is detected.
When in protection mode the unit is prevented from starting by protection circuit, so to prevent further damage.
Check the speakers and speakers wiring, a contact in speaker wires, or faulty speakers can send the unit in protection.
Try unplugging power cable for one hour or so. then connect cable back
and see if you get rid of protect state. Sometimes accumulation of
electrostatic charges inside circuit capacitors can kick in protect
mode. In that case unplugging the unit from main for some times can get
rid of electrostatic charges, and reset circuits by draining power
completely.
If that was the problem, you will not get Protect when plugging back power cable.
If you do all the above and still get Protect, then there is a real fault.
In that case the unit may be disassembled and tested to find the fault.
If that is the case I suggest contacting the manufacturer at the number
listed on the owners manual, or asking a quote on repair to a local
technician.
Hi Techman,
Thanks for the suggestion . I think what I did confirms that the main processor is working fine . When I checked the speaker outs with a MM before I cut the protect link wire , I had what appeared to be a slight low voltage leakage on the centre speaker with all others being stable .
Yes I have a PDF of the sevice manual , which I can send you if I can have an email address to send it to.
Cheers
Malcolm
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