| skappy |
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 |
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| odysseybmx414 |
| nothing happens? maybe the plug hooked to your pc soundcard is in the wrong jack. because usually when theres something wrong with an amp it will hum or "motorboat" or do something odd |
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| odysseybmx414 |
| did you try a diff source such as dvd player or cd player? |
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| skappy |
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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| carlosfm |
| Are you using a heatsink? |
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| neutron7 |
| can u attach a picture of the board and connections? |
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| john65b |
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 |
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| skappy |
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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| Nordic |
| Hey skappy, you can add multiple images to one post... simply insert image, post, then hit edit, and specify next image... rinse and repeat...:cannotbe: |
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| skappy |
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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| john65b |
Damn, I was just about to suggest fully conecting up the power supply board...
Good deal |
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| skappy |
Yes !!!
I'm quite happy ....
I don't really understand why but as soon as it works ... |
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