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Ps-400 buzzing when i turn on my amp the power led and both channel leds all light up and it starts buzzing. i have had this amp for years and let it on by accident

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  • Anonymous Mar 31, 2014

    On powering on the amp, all input LEDS are flashing

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  • 319 Answers

You may have an open capacitor in power supply. Replace cap

Posted on May 10, 2008

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The Amp clip light is always ON only the left channel and the same channel is not functioning by giving sound, please help


I looked at a schematic for EP2500 which is same but has a lower buss voltage than the EP4000. Below, the drive signal to the power stage is full wave rectified to illuminate the LED, d-c is presented to the LED if R128 & R138 has an a-c return. There is a line that can push-up the a-c return. It goes off to a connector that is unknown. I suspect the push-up voltage is not there. It could mean anything. I think its coming from the main transformer, Check for blow fuses.
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Also the speaker output is protected with a "Crowbar" circuit. It is simply a Triac device (light dimmer) or two SCRs to prevent d-c from shorted output devices being applied to the speakers. which would cook the speaker coils. This may be activated when amp is turned on. Then there is the possibility of the output power devices - one or more shorted.
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The amp needs to be checked out by a repair technician.

Feb 04, 2016 | Behringer EuroPower EP4000 2Channel...

1 Answer

Dhd amp has power but blue leds flash once and turn off. the led in the back lights up green but the blue leds that light up in the front flashon once, and then turn off. it won't let me sub hit.


Dhd amplifierDisconnect 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. Double check all connections .A thumbs up would be greatly appreciated if this answer is helpful to you. Worth fixing.

Feb 05, 2015 | Amplifiers & Preamps

1 Answer

Sound from only one channel


Turn off the other channel and listen only to the bad channel playing some music. Turn it up! If you hear any music the pre-amp is working and the power amp is faulty. If you don't, then the pre-amp is faulty.
Because it's a stereo amp you have the good channel to compare with the bad. So you can do voltage tests, or "buzz" tests. Buzz Tests or where you apply a insulated tool to the circuits, a buzz will be heard. If it buzzers in the good channel it should in the bad. Ignore the power supply and don't short any parts out!

Sep 12, 2013 | Rotel Amplifiers & Preamps

1 Answer

Legacy 1000w 2 channel amp worked awesmoe then just stopped working after a few songs. Didn't turn up too loud. Didn't have the settings too high. still getting power (amp light on, led lights...


Open your speaker box up most likely the jumper from the inside of the box to the subwoofer itsself is broken free, Usally when they have lights around the sub woofers there seperate leads, bet 10-1 you have loose wires inside the speaker box

Mar 25, 2013 | Legacy Audio ICON LA2770BK 1000W 2-Channel...

1 Answer

Adcom GFA-7400 power amp; 1 dead channel (thermal protect LED on)


Hi...

I've contacted ADCOM before and they sent a pdf of the electricals

http://www.adcom.com/default.aspx

also try:

www.stereomanuals.com

Mar 30, 2010 | Adcom GFA-7400 5-Channel Amplifier

1 Answer

Preamp is not working,a main component has failed,do not know which component but do know that it is in the pre amp,will not turn on or power the other 2 amps


If you have lost both channels then it's something that is common to both that has gone. If one channel has gone, use the good channel as a guide. Here's what to do find the point where the pre-amp outputs to the power amp. With a screwdriver touch that point (make certain you only touch one metal point at a time = don't short anything). It should buzz! work backwards till the buzzing stops. It is easier to test with a channel working, but I think you will soon get to the faulty stage.
PS IC's are allways suspect when both channels out!
PPS Don't touch any power parts with the screwdriver!

Jan 08, 2010 | Amplifiers & Preamps

1 Answer

Technics su-z250 left chanel is not working


You need to determine if the fault is in the pre-amp section or power amp part. Look around for damaged or burnt parts. If you turn up the volume on the left channel and you hear a weak signal then the pre-amp will be OK. If not then start with that section. Remember the right channel will be the same as the left so compare the parts. If it looks odd in the left it might be the faulty part!
You can apply the Buzz test! Being careful not to touch the power supply parts, touch the two channels in various places with a srewdriver. On the right you should get a buzz showing the signal is there, so touch the left in the same place! And so on...PS don't short anything with the screwdriver!

Jan 02, 2010 | Technics Amplifiers & Preamps

1 Answer

Cambridge Audio Azur 340A amplifier,no sound


Start with the basics first. 1. With the amp on, in each imput socket plug a dual end phono cable in and touch the right and left plugs with your finger. You should get a buzz on each speaker. No buzz and the channel at that terminal is not working. If none of the terminals buzz. Then the amp is dead.
If some buzz and others not you have a pre-amp problem.
2: Amp Dead. Could be A power supply. B main pre-amp. C Power Amp.
The power supply check for a fuse.
The main pre-amp will only effect both channels if an IC controls both.
The Power Amp will again only loose both channels generally if it is an IC. It will be attached to a big heat sink and have lots of pins comming from it.
If it uses transistors for the main amp, you can check these with an Ohm meter. With the power off place the leads on each terminal of each transistor. If the meter goes fully over (like when you touch the leads together) each way it has shorted.
The thing to remember when repairing stereo amps. Is that the amp is two identical amps joined together. So what happens one side will happen on the other. If both channels don't work look for something that is common to both.
Good luck
PS never heard of 'cliperd'.

Sep 25, 2009 | Cambridge Audio Azur 340A 2-Channel...

1 Answer

Unbalanced LEDs> amplification problem, or mere graphic drop out?


This could be a defect in the metering circuit. In order to verify this, you should measure the output externally. Get that external measurement and post the results here. We'll continue from there.

Dan

Apr 12, 2009 | Yamaha DSP-AX1 10-Channel Amplifier

2 Answers

Question on BB2125 2 Channel Amp


Hi jgoudie

It is a signal sensing turn on unit, so will not turn on until you have supplied signal to it. Plug it into a signal source and see what it does. But unfortunately, in my experience the protection light coming on means there is a fault in the amp.

You can download the user manual for the amp from here. Click downloads in the middle of the page:)

regards
robotek

Aug 17, 2008 | SpeakerCraft BB2125 2-Channel Amplifier

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