Need Help ... Briangt Kit LM3386 doesn't work

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Hi Everybody,
This day should have been the great day as i have just complete the construction of my first BrianGT Kit (LM3886).
I've plug a jack in a PC sound card as Input.
I've connected V+,V-, PG+ et PG- from power supply (300VA, 30 Volts & 5 Amps) to Main card ...
i've connected the mlain card to loudspeaker but nothing happens ...

Where should i search ?
Power supply works as i have 41 Volts on the main card


Thank you very much for your ideas
 
the pc sound card is OK, i've checked it with a another amp...
I have test the Amp with another source (portable cd player) but nothing happens ...

I would like to add that i have not use any potentiometer between sound source and the amp but as the volume was set by the Pc it should not be a problem ...
 
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I bet...

Are you suing BOTH Rectifier Circiuts with Dual Secondaries (ie, do you have two hots and two neutral legs coming form your transformer correctly attached to the PS Board?)

If you have two hots and a single Center Tap, you need to use only One rectifier circuit. Look into how the Transformer is wired for ONE Rectifier circuit on the LM3876.pdf instructions, as it does not go into this variance on the LM3886.pdf instructions.

I wired it up "incorrectly" on mine and still showed +40V -40V unattached to the amp board, but when amp boards connected, I kept blowing fuses neutral fuse (I had dual fuses on Nuetral and hot)... I could not get mine to work until I removed the 4 inner diodes and jumpered them per the LM3876.pdf.

Works great now.

My 2 cents
 
Hi Everybody,
thank you very mucj for your attention and your help ...
yes , i have used a Heatsink for the LM3886
i think that my connections to the power supply is correct but i have to add that i've only plug only one way , the other one is not connected and i have observed tyhat in one case, i have something like 2 volts at the loudspeaker output, and when i change the power plug to the other way i have 0.4 volts ...
I can't undertstand

I've joined somes photos in the next messages if ithey could help...

Thank you very much for your help
 
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Hi again ,
finally, problem has been solved just now ...
This problem was caused by the fact that i've plug only one way of the power supply, second was left free ...
So , good sound has emerged when i plug the other way

Thank you very much for your assistance

Good Luck in your projects & see you
 
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