Yamaha dc protection remedy

"My Yamaha receiver RX v575 will not power up it has a blinking red light when trying to power up "
Never press power button more than 3 times. Your amp will be locked, otherwise.
(1)Download RXV575 service manual.
(2)Read P.25 to 29 to see if protection occurs.
(3)Read P.31 and follow the diag steps.
(4)If I protect, check all power transistors,two
0.22Ohm resistors and biasing circuit such as
all components connected to Q2022 of front L channel, on P.108.
(5)If dc protect, check if DC comes out from speaker terminal, opening metal cover required.
(6)If thermal protect, replace a thermal sensor.
(7)If power supply problem, ps prt, check all
power supply circuits, including regulators and
caps.

5 seconds shut down: dc protection triggered. (DC outputted from speaker terminals.)Make sure +B and -B are equal first . The problem also comes from voltage amp circuit board including differential amp and constant current source but power transistors mounted are ok. Remember to download HTR 6130 service manual .

There are, at the very least, a few different types of protection, DC Offset, Thermal Overload, or simply a voltage from a sensor transistor to the microprocessor IC,(display microprocessor) that communicates with the main microprocessor IC, one of the computers in your unit) to open the AC relay. If require more assistance, or would like to inquire about repairing your unit, please visit my website at audioserviceclinic.com. Thank you.

Are speakers connected when you try powering up?

If so , you have an output imbalance where there is too much DC voltage on one of the outputs and the Protect is working OK....In my opinion , not worth getting repaired ( UNless you're a tech and can do it yourself)

hello,
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Also check for cracked solder connection.
Good Luck

you don't want to do this( bypass the protection0
that d.c. output will burn the coils in your speakers with out making a sound!! you have a biasing problem
or like you said a d.c. offset problem it is best to work on this problem with out a load on the amp, this will allow you to trace back where the trouble is starting at. caps will cause this sort of problem but leaky transistors can also do this, even diodes.
this will require an experienced trouble-shooter.

Sounds like you have a bad amp IC or transistors.
When these go bad they almost always put roughly 40 volts dc from the amp power supply to the speaker terminals. The protection circuit senses this dangerous (to your speakers) dc voltage and disconnects the speaker terminals from the amp via internal relays (the ones you hear click) and puts it into protect mode. If it didn't the dc voltage would quickly toast the voice coils of the connected speaker.

Hi friend,when something goes wrong in the output of the amplifier the protection circuit take place to prevent further damage could cause by DC power such as speakers or other related circuits...I think in your situation either one or both output amp stage have blown,then the protection cct turned on (not blown protection circuit!?). If so you have to check all the output transistors for short cct, if shorted you must also check all the DC bias cct nearby such as small transistors,resistors...If you are not familar with amplifier it better to find a tech as all amplifiers need a very precide repair technic , If the DC BIAS were wrong , when you turn on the power it will blow straight away! All times and cost will be waisted!
GOOD LUCK!
Tan Ta

there is a bulb inside the backlight on the lcd display.it is 12 volt and alot of manufacturers run it from the +- 15 volt preamp power supply,on the plus rail.when the bulb burns out it can activate the dc speaker protect,or some other 12 or 15 volt circuit..if it is a flourescent display that is a different problem.those run on 5 12 18 and -32 volts.there is also a 6 volt ac filament voltage.you need the schematic.

Protect delay is in the relay and not adjustable as to delay time.
I would not worry unless no sound then may have to replace relay.

GOOD LUCK
BIG RED