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Old 11th May 2005, 09:24 PM   #1
ledim is offline ledim  France
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Question Strange connection on SI T-amp PCB

Hi,

at least two people on a french forum have found a strange cable connection between the positive side of the input cap of the Sonic Impact T-amp (C10) and the C11 cap (left side when reading C11) when they opened their t-amp
See this post for a picture and a better idea of what I'm trying to say:
http://www.homecinema-fr.com/forum/v...649&start=1230

On the 3 ones I've received recently from thinkgeek, none of them had that. Mine didn't have the heavy soldering on the back of the pcb (as on the picture) but rather a series of holes.

2 questions:
. who found this connection on their T-amp ?
. what could be the purpose of it ?
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Old 12th May 2005, 01:07 AM   #2
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One of the three amps that I got from Think Geek in mid March had the same connection. I assumed at the time that it was a bad trace but didn't bother to check it out. I was going to try a continuity tester on another amp to see if there is normally a connection between those two points and then disconnect the mystery wire on the first amp and check again. Never got around to it.
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Old 13th May 2005, 05:14 PM   #3
KT is offline KT  United States
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The picture is blurry so it's hard to tell exactly where the wires are connected, but those points look familiar to me.

The point on the board at the top of the photo, the blank point between the two SMD caps, connects to the + power input of the chip (and connects to the inner ends of both SMD caps). I know this because I followed the power traces around the board and ended up hard-wiring my + power right to that point between the two SMD caps to bypass the board's tiny power traces.

I think the point near the lower side of the board is the power supply cap.

If this wire is connected to where I think it is, it's probably done so in order to bring the + power from the power supply cap to the chip on a bigger rail than than what's provided with the little traces that are on the board.

It's hard to tell exactly by the blurry photo, though.

Best,
KT
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Old 13th May 2005, 07:15 PM   #4
ledim is offline ledim  France
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Thanks for the info KT.

Quote:
I know this because I followed the power traces around the board and ended up hard-wiring my + power right to that point between the two SMD caps to bypass the board's tiny power traces.
I've already upgrade the input cap to a 1000uf ELNA Silmic II by desoldering the original input cap and put the ELNA in place. Do you think I can wire direcly the - power direcly to the negative side of the cap, or do you have other SMD components between the input cap and the point where the original - power is soldered on the pcb ?
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Old 14th May 2005, 06:46 PM   #5
KT is offline KT  United States
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Ledim,

I didn't look too closely at the negative side of the power rail. I just hooked up the negative connection to the pad that it normally connects to. I'm not sure if by moving the connection further forward you might not be cutting some connections off due to jumping over diodes, etc. Maybe it can be done, but I haven't looked at it closely enough to be sure.

Best,
KT
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