USB Cable Connected, no Red LED. Not Connecting to Computer

[dmserve]

I am assembling another 3D printer, and ready to upload the firmware to the Printrboard.
Plugged in the USB Cable and no Red LED.
Not connecting to computer.
(I am using cable that works on other machine)

Can you help?
Can you Replace the Board?

This is the 4th machine I have used the Printrboard for.
I have not had this problem before.
_________________________

ALSO!!

The 12vdc header is installed backwards.

Look at your auction picture, the notch of the atx header is pointing to the chips on board.
The one you sent me has the atx header pointing at the edge of board.
This is backwards,
This will not work

Here is a link to the 4 pin Molex plug.
http://en.wikipedia.org/wiki/Atx#Power_supply

scroll down a little, and you will see the diagram.

This shows pins 1 and 2 are Gnd.
and shows pins 3 and 4 are +12vdc.

This is the standard for ATX Power Supplies.
That have been used in MANY computers!

AND:

The trim pots are not as auction shows.

I bought the board because of the picture.
It was pictured as the board that worked for me in the past.
And that is what I expected to receive!!
If you are changing the style of a product you sell, Take a new picture!!!
I would NOT of bought this board if was correctly pictured!!
or was that your plan?

Will you replace this board?
How soon will you get back to me?
________________________

I am still waiting on answer to different problem dated Oct. 21 2013.
How much longer do I have to wait for that answer???????????
This Printrboard was from a different Vendor, but believe you are SIGNING UP AS DIFFERENT VENDORS to sell you products.

Very misleading to the public.
Bad way of doing business.

[Alex-w]

sorry this boring you,do you ever plug the 12 power on the board?
PLS check the point is soldered。

[dmserve]

No, I did not plug in the 12vdc.

Yes, the USB is soldered.

[Alex-w]

not usb，it is power’s selecting。

[dmserve]

Yes, 2 small lines of solder.
Same as the Picture.

[Alex-w]

1.you shold set the multimeter like that

The attachment IMG_4021.jpg is no longer available

2.make sure that +5（ red Probe）v is not short with gnd（black Probe ）

IMG_2426.jpg (251.95 KiB) Viewed 16922 times

[dmserve]

Yes, from the 5 volt pin (shown in picture) to 12v (atc plug) ground is shorted.

[Alex-w]

i think if you don't pulg 12v power on，there are some short circuits in D1/C1/C12/C20/C25/C30。you can remove it one by one ，then test that does there has short between +5v and gnd

[dmserve]

Previous Test:
I am testing with NO USB power and No 12vdc Power
I tested the 5 volt pin (shown in picture) to 12v (atx plug) ground, this is shorted.

I have never put 12vdc to this board yet.
I have only plugged in the USB cable.
__________________________

New Test:

I do not under stand what you mean by "remove it one by one"
Remove what??
Remove how??

[Alex-w]

Using that Electric iron welding diode D1 and Capacitance C1/C12/C20/C25/C30 down.