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Old 16th May 2016, 04:36 PM   #1
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Default Parasound A21 problem

Hi,

Is there anyone here using Parasound A21 or familiar with it?

I've just got a problem Parasound A21 from a friend of mine. He just said cant power on the amplifier.

Tonight I tried to power on the amplifier with only power cord. There are nothing connected at back panel. And there is only a red light appear behind the "P" logo at front panel when pressing power on button. Is it normal? Since the operational manual said blue light should glow behind the power button but never turn on at my Parasound A21.


The settings at back panel are as below:

All input/output are didn't connect
Auto turn on: Auto
Ground: Normal
Inputs: Unbalanced

And I have checked all the fuses didn't blow and all capacitors didn't leaks.

Hope can get some clue here.

C.W
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Old 16th May 2016, 04:56 PM   #2
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If the relays do not pull in, there is probably DC on the output. Check for DC.
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Old 17th May 2016, 02:22 PM   #3
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Thanks JonSnell for your suggestion. I have found that there are no output voltage (AC) from toroid transformer before bridge rectifiers. I will start here and trace back to
line voltage.

C.WClick the image to open in full size.
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Old 17th May 2016, 06:43 PM   #4
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I had an A-23 and when it was set to Auto on "Auto Turn On" it would only come on with either a 12v trigger or an audio signal present at its input.
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Old 17th May 2016, 07:50 PM   #5
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Quote:
Originally Posted by rczetli View Post
I had an A-23 and when it was set to Auto on "Auto Turn On" it would only come on with either a 12v trigger or an audio signal present at its input.
That is what Parasound's specs say! "Auto turn-on by 12v trigger or audio signal, 12v trigger out"
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Old 18th May 2016, 03:50 PM   #6
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I tried to turn off "Auto Turn On" function by switching to manual. I noticed that the only dark red light behind "P" logo. My only question want to know at this moment is that whether any blue light turning on at front panel?
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Old 25th May 2016, 12:21 AM   #7
phase is online now phase  United States
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Can you remove the fuse from one channel or the other and still get the same results?
My HCA-1000a has three lights; plugged in to the wall; standby/protect; and powered on.
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Old 27th May 2016, 04:37 PM   #8
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I have tried to remove the fuses in combination(remove either one channel, and remove both channels). But it still shows red light behind "P" logo. So I will trace between AC in and fuses. Thanks for your suggestions phase.
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Old 27th May 2016, 06:36 PM   #9
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I have just bought a new A21. The red light behind the "P" is always on if the power lead is connected. The manual says there should also be a faint blue light behind the power switch; there isn't. The blue light comes on when the amp turns on, and the red light gets brighter.
I don't know if that helps.
Oh, and I am using the auto function which turns the amp on when it detects a music signal, but it is the same with the manual setting.

Last edited by awkwardbydesign; 27th May 2016 at 06:39 PM.
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