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How can I reset the Protective Circuit? HITACHI Stereo Power Amplifier HMA-G2

Something went wrong when connecting the amplifier and the protective circuit was engaged. Now the little green light "Protective" just goes on blinking. Normally it would keep blinking for a couple of seconds and then turn to steady green. This little green light is situated right between the hudge Vu:s.

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6ya6ya
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Posted on Jan 02, 2017

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ampman
  • 98 Answers

SOURCE: No Audio From Amplifier

I would first check for "rail votage" at the rectifiers... If all of your audio transistors are not getting around 40 volts then check the transistors you replaced. They should be getting a 5 volt (10 volt square wave is checked with a scope) "drive" signal. If half of your power supply transistors are not getting a drive signal then replace the kia494/tl494/kia594/tl594---whatever it is. thats the ic chip that supplies the "drive" signal to the power supply transistors. Also follow the board closely out of the power supply transistor to the 494 chip.. there should be some small driver transistors in between.. make sure they are not shorted or fried as well... let me knoe if you need more help

Posted on Aug 18, 2007

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SOURCE: Amp Power light will not go on. Protection light is lit- Thump sound in speakers

It probably has shorted output transistors. To eliminate other possible causes, read through the following page.

Amplifier in Protect Mode - Troubleshooting

Let me know if you have any other questions.

Posted on Nov 02, 2008

  • 4 Answers

SOURCE: Amp Turns on Fine, but no Sound

have you checked the levels on the ohms? adjust them higher if need be contact me on yahoo msgr if you need more assistance

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Posted on Dec 03, 2008

  • 323 Answers

SOURCE: Amp on "protect" mode

Hi, what you need to do is unplug all the connections to the amp. The amp goes into protection when the circuitry over heats.\
First decrease all your gains to minimal volume.
Connect your 12+V, remote, and ground.
See if the protection light comes on then.
Next plug in your RCA cables.
Check protection light.
Then plug in your subwoofer cables.
See if you are still in protect mode.
Hopefully everything works alright again.
Just slowly increase the gain to see what the cut-off is. Make sure you aren't dropping the ohmage too low on the amplifier. Check manual for correct wiring and such.

Posted on Feb 09, 2009

  • 8 Answers

SOURCE: Pioneer GM-7200M 800 Watts Mono Amplifier

you Amp is overloading and going into protection mode. if it cuts out with the wire u were using first then their would be no need to upgrade the size of ur wire cause that would only be, doubling or trippling the power u are getting threw those wire now. bottom line the 2 subs u are using are obviously to much for the amp. try dropping the OHM's by connection the subs together and runnig just a single positive and negative to the amp! or just get a better amp

Posted on Jun 10, 2009

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Protective mood


Disconnect all speaker connections and rca cables. Leave power, ground and remote wires intact. Try turning on again. If you still have a protection light your amp is faulty. Hopefully you have warranty. Hopefully its not toast. .A thumbs up would be greatly appreciated if this answer is helpful to you. protective-mood-zb4bomd1rt4qms0dqd12kkt2-2-0.jpg

Jan 16, 2014 | Car Audio & Video

1 Answer

Our receiver automatically shuts down, showing 'protect' in the display, when volume is turned up to -30 db. How can we stop/reset this? We really appreciate your answer.


hi,
First of all remove all the speaker connections from the amplifier. After that power the amplifier and check the protect show or not . if not, then any of the speaker is damaged. If its goes to protection mode when you incrase the volume then check the impedance of your speakers it should be 4ohms or above . Test with some other speakers if available.

Amplifiers gose protect mode , when there is a hardware fault in side it. Its a warning that some thing is wrong.
Normally amplifiers show this when any of the output amplifier have some problem. there are two amplifiers stage left and right . May occur when the output diver transistors of any of the amplifier become shorted. if the output transistor get shorted this will lead to flow of current through the speakers. To prevent this there is a protection circuit for each channels. One combined output of this protection circuit is connected to the system control. when the any of the output amplifier fails, the protection circuit detects it and switch of the speaker and sent data to the system control. when the system control get this data it will give a warning to the customer through display that PROTECT.
You have to check the amplifier.
For that you need digital multimeter,soledring iron screwdrivers etc
Open the amplifier , then power it on. Connect the negative terminal of the multimeter any where in the chase( metal body of the amplifer). Then connect the positive terminal to all the output transistors emitter pin one by one . The voltage should be bellow 0.5V. If any of the emitter of the transistor shows voltage more than +/- 0.5V., then that amplifier stage is faulty. Remove the transistors and check it. if it is shot then replace with a new one.
After replacing the transistors do not power up the amplifier directly from the main. You have to put a bulb of 60 watts in serial.
You can do this easily remove the mains fuse. Put the bulb in a holder. Now you have two wire from the holder. connect one of it to the one end of the fuse holder and the other wire to the other end of the fuse holder. Why using a bulb is, if there is any further problem in the amplifier stage on which the transistors replaced, there is a possibility of the new transistor get damage. if we use a bulb in serial with its mains supply ,when any overload in the amplifier occur the bulb will drop the current, by lighting itself.
After connecting the bulb in serious power on the amplifier. watch the bulb. It should light for one or two second and go dim ,then remove the power , remove the bulb insert fuse and connect the power and check.
(If the bulb shows bright light then there is some component also faulty in the same amplifier. after removing the power you have to check again the amplifier stage of which the transistor is replaced, for any other faulty components.
ok

Jun 13, 2011 | Marantz SR4021

1 Answer

My sub woofer wont work? the stereo turn on then it shuts back off.


hi,
First of all remove all the speaker connections from the amplifier. After that power the amplifier and check the protect show or not . if not, then any of the speaker is damaged. If then also it shows protect you have to check the amplifiers hardware.

AV receivers shows protect mode , when there is a hardware fault in side it. Its a warning that some thing is wrong.
Normally AV receivers show this when any of the output amplifier get some problem. there are six amplifiers in this AV receiver. May occur when the output diver transistors of any of the amplifier become shorted. if the output transistor get shorted this will lead to flow of current through the speakers. To prevent this there is a protection circuit for each channels. One combined output of this protection circuit is connected to the system control. when the any of the output amplifier fails, the protection circuit detects it and switch of the speaker and sent data to the system control. when the system control get this data it will give a warning to the customer through display that PROTECT.
You have to check the amplifier.
for that you need digital multimeter,soledring iron screwdrivers etc
open the amplifier , then power it on. connect the negative terminal of the multimeter any where in the chase( metal body of the amplifer). then connect the positive terminal to all the output transistors emitter pin one by one . the voltage should be bellow 0.5V. If any of the emitter of the transistor shows voltage more than 0.5V., then that amplifier stage is faulty. Remove the transistors and check it. if it is shot then replace with a new one.
after replacing the transistors do not power up the amplifier directly from the main. You have to put a bulb of 60 watts in serial.
You can do this easily remove the mains fuse. put the bulb in a holder. now you have to wire from the holder. connect one of it to the one end of the fuse holder and the other wire to the other end of the fuse holder. Why using a bulb is, if there is any further problem in the amplifier stage on which the transistors replaced, there is a possibility of the new transistor get damage. if we use a bulb in serial with its mains supply ,when any overload in the amplifier occur the bulb will drop the current, by lighting itself.
After connecting the bulb in serious power on the amplifier. watch the bulb. It should light for one or two second and go dim . if so check the display, is there is protect mode is on or not . if not and come back to normal operation ,then remove the power , remove the bulb insert fuse and check
connect the power and check.
If the bulb shows bright light then there is some component also faulty in the same amplifier. after removing the power you have to check again the amplifier stage of which the transistor is replaced, for any other faulty components.
ok

Mar 08, 2011 | Pioneer SX-315

1 Answer

My rx-v367 does not power on, i think the protective circuitry has been activated. How do I reset it?


hi,

AV receivers shows protect mode , when there is a hardware fault in side it. Its a warning that some thing is wrong. Is there is any standby light. If not check the AC fuse.
Normally AV receivers show this when any of the output amplifier get some problem. there are five amplifiers in this AV receiver. May occur when the output diver transistors of any of the amplifier become shorted. if the output transistor get shorted this will lead to flow of current through the speakers. To prevent this there is a protection circuit for each channels. One combined output of this protection circuit is connected to the system control. when the any of the output amplifier fails, the protection circuit detects it and switch of the speaker and sent data to the system control. when the system control get this data it will give a warning to the customer through display that PROTECT.

First of all remove all speaker connections from the amplifier and powerup the amplifier. If the amplifier turns ON then, then any of the speaker have some problem.
If not You have to check the amplifier.
for that you need digital multimeter,soledring iron screwdrivers etc
open the amplifier , then power it on. connect the negative terminal of the multimeter any where in the chase( metal body of the amplifer). then connect the positive terminal to all the output transistors emitter pin one by one . the voltage should be bellow 0.5V. If any of the emitter of the transistor shows voltage more than 0.5V., then that amplifier stage is faulty. Remove the transistors and check it. if it is shot then replace with a new one.
after replacing the transistors do not power up the amplifier directly from the main. You have to put a bulb of 60 watts in serial.
You can do this easily remove the mains fuse. put the bulb in a holder. now you have to wire from the holder. connect one of it to the one end of the fuse holder and the other wire to the other end of the fuse holder. Why using a bulb is, if there is any further problem in the amplifier stage on which the transistors replaced, there is a possibility of the new transistor get damage. if we use a bulb in serial with its mains supply ,when any overload in the amplifier occur the bulb will drop the current, by lighting itself.
After connecting the bulb in serious power on the amplifier. watch the bulb. It should light for one or two second and go dim . if so check the display, is there is protect mode is on or not . if not and come back to normal operation ,then remove the power , remove the bulb insert fuse and check
connect the power and check.
If the bulb shows bright light then there is some component also faulty in the same amplifier. after removing the power you have to check again the amplifier stage of which the transistor is replaced, for any other faulty components.
ok

Feb 17, 2011 | Yamaha RXV367 Receiver

1 Answer

Harman Kardon receiver in protect mode. Removed all contections and done reset ... still same issue


hi,

AV receivers shows protect mode , when there is a hardware fault in side it. Its a warning that some thing is wrong.
Noramlly AV receivers show this when any of the output amplifier get some problem. there are six amplifiers in this AV receiver. May occur when the output diver transistors of any of the amplifier become shorted. if the output transistor get shorted this will lead to flow of current through the speakers. To prevent this there is a protection circuit for each channels. One combined output of this protection circuit is connected to the system control. when the any of the output amplifier fails, the protection circuit detects it and switch of the speaker and sent data to the system control. when the system control get this data it will give a warning to the customer through display that PROTECT.
You have to check the amplifier.
for that you need digital multimeter,soledring iron screwdrivers etc
open the amplifier , then power it on. connect the negative terminal of the multimeter any where in the chase( metal body of the amplifer). then connect the positive terminal to all the output transistors emitter pin one by one . the voltage should be bellow 0.5V. If any of the emitter of the transistor shows voltage more than 0.5V., then that amplifier stage is faulty. Remove the transistors and check it. if it is shot then replace with a new one.
after replacing the transistors do not power up the amplifier directly from the main. You have to put a bulb of 60 watts in serial.
You can do this easily remove the mains fuse. put the bulb in a holder. now you have to wire from the holder. connect one of it to the one end of the fuse holder and the other wire to the other end of the fuse holder. Why using a bulb is, if there is any further problem in the amplifier stage on which the transistors replaced, there is a possibility of the new transistor get damage. if we use a bulb in serial with its mains supply ,when any overload in the amplifier occur the bulb will drop the current, by lighting itself.
After connecting the bulb in serious power on the amplifier. watch the bulb. It should light for one or two second and go dim . if so check the display, is there is protect mode is on or not . if not and come back to normal operation ,then remove the power , remove the bulb insert fuse and check
connect the power and check.
If the bulb shows bright light then there is some component also faulty in the same amplifier. after removing the power you have to check again the amplifier stage of which the transistor is replaced, for any other faulty components.
ok

Feb 12, 2011 | Harman Kardon AVR 35 Receiver

1 Answer

Thumping speakers - no power light is on - wired correctly


the amp is going into protect mode due to something wrong in the amp or some thing in the wiring to it ooh yea if you are getting 18v power to the amp that is way to high it should not be higher then 15v if the amp is in protect mode it will not play at all.

Nov 02, 2008 | Visonik Dual Bass Box with Amplifier Car...

1 Answer

Amp Power light will not go on. Protection light is lit- Thump sound in speakers


It probably has shorted output transistors. To eliminate other possible causes, read through the following page.

Amplifier in Protect Mode - Troubleshooting

Let me know if you have any other questions.

Oct 31, 2008 | Visonik Dual Bass Box with Amplifier Car...

1 Answer

Amp will not turn on


That is the way it should be connected. If the protect light comes on you have a different problem than the power connections.

Try to turn it on withour any speakers connected, if it turns on then, you have a bad speaker or you may may the speakers connected inproperly.

If it still goes into protect you have an internal problem with the amplifier.

An internal problem would be something you would need a professional technician to check out. Could be in the power supply circuit, but most of the time it is a blown channel.

If you require any more help feel free to ask,
And if you found this advise to be helpful a "FixYa" rating would be appreciated.

Thanks,
Dave

Jun 25, 2008 | Car Audio & Video

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