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Old 6th October 2011, 10:00 PM   #1
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Default Help; Blown up lepai LP2020A+

Hi,

I have the Lepai LP2020A+ (Smd version) and I got an external battery for mine and when connecting the battery to the amp I got the polarities the wrong way round and think Iíve blown it!!


It all seems to work but just doesnít let any sound out the speakers.
I cant see any component or track burnt or anything.


When I flick the switch the blue light turns on and if I put my ear close to the amp and with no speakers attached I can hear the music playing very faintly (I think its those round black things with 100 written on them).

Has anyone got any suggestions for what I can try or possible things that could be wrong with it.

-Thanks
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Old 12th October 2011, 10:04 PM   #2
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Just to add when i used to switch my amp on it used to make a clicking noise like a replay clicking on but now it no longer does that!
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Old 13th October 2011, 06:41 AM   #3
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Do you have a multimeter, or anything else that could be used to troubleshoot?
You could use a signal source, with a 1uF cap in series at one end of the wire, and touch the other capacitor lead to pin 10 or pin 13 of the TA2020 chip. While the unit is powered on. If you don't get audio out to the speakers, put your Lepai in your junk box for parts and buy a new one.
This is intentionally brief. Further details on request.
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Old 16th October 2011, 04:01 PM   #4
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Ok done a bit of testing today and it seems like the TA2020 chip is working just fine as I measured pins 10 & 13 and they were 2.5 each. I then connected a speaker to pins 21 & 23 and another speaker to pins 24 & 26 and the sound came out the speakers just fine and also what I wasn't expecting was that the volume control still was controlling the volume.

Could I just solder a wire from them pins straight to the output/speaker block and miss everything in between, would that be safe or a bad idea?

Its hard to work out which components and in between the the TA2020 chip and the output speakers connection block on this board, can anyone identify which ones are and then I can try and eliminate them one by one and fingers crossed get it working.

-Thanks
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Old 16th October 2011, 05:04 PM   #5
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Quote:
Originally Posted by Motsey View Post
Could I just solder a wire from them pins straight to the output/speaker block and miss everything in between, would that be safe or a bad idea?
That would be an incredibly bad idea. And if you do it will probably land you in jail, or at the very least land you a huge fine. Spread spectrum RF noise transmitters are generally frowned upon in any country.
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Old 16th October 2011, 09:24 PM   #6
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It seems from the testing I have done that the component that is failing is the "Omron G5PA-2"
does this sound right or would this component failure not cause the amp to light up and sound not to work?

I am trying to source this component and see if its cost effective to replace, anyone know where I can get it or an equivalent from cheap?

-Thanks
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Old 16th October 2011, 09:55 PM   #7
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just a thought could I bypass the Omron G5PA-2 but just on the pins for the negative speaker terminals? would that be a bad idea/ illegal or dangerous?
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Old 16th October 2011, 10:01 PM   #8
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You can bypass the relay, yes. Just make sure you're not bypassing any of the output filter components.
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Old 26th July 2012, 01:49 AM   #9
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Well Motsey? Did it work? I did the exact same thing today. Medium sized bang sound. Then lights on, no sound.
Nothing looks scorched on the PCB.
Maybe if i check out the audio input to the relay, see if anything is going in.
I only just got my amp too. Doh!
Still, only £14 GBP, can buy a new one, but I'll have to wait for shipping.
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