GTX 1660 - PLEASE POWER DOWN AND CONNECT THE PCIEe POWER CABLES(s)

albobbyD

n00b
Joined
Mar 3, 2021
Messages
7
Hi everyone,

I've got a GTX 1660 with a strange fault. On boot "PLEASE POWER DOWN AND CONNECT THE PCIEe POWER CABLES(s)" message appears.
Checked and re-checked the 8 pin connector on the board and on the power supply side.
I've seen that on Sense pin I've got around 3.1V without the connector. If is plugged in it goes to ground.
I've got some troubles in identifying some components. U1 has an "L2" marking and D1 a "KL7" marking.
I manage to draw a schematic with what I figure out so far.
I will need some help in identifying those components. I usually repair graphics card with Power Stage / VRM issues and I don't really understand
how the sense voltage drop is detected and by who.

Thanks in advance.

1614785411121.png
 

RazorWind

2[H]4U
Joined
Feb 11, 2001
Messages
3,856
Can you post a photo of the board - particularly the area near the PCI-E connector?
 

Armenius

Fully [H]
Joined
Jan 28, 2014
Messages
24,618
How is the video card being connected in the PC? I think this needs to be established before trying to diagnose a board issue.
 

albobbyD

n00b
Joined
Mar 3, 2021
Messages
7
Yes, I've got +12V on both ends. Checked all the fuses. The Video Card is Connected to a test bench.
 

albobbyD

n00b
Joined
Mar 3, 2021
Messages
7
Okay, so how is power being connected to the video card in your test bench?
Honesty I use 2 power supply's. Ground is common (linked together). The motherboard is from a Dell Optiplex 3020. To power the test bench I use the original power supply. To power the video cards (External PCIe connectors) I use a server one. It could handle around 70 Amp on 12V. Ground is linked together between the power supply's. The card was bought faulty from eBay with this fault. I've tested dozens of cards with this bench and they worked just fine. The issue is with the card. I don't know how the sense pin is detected by the card. There's a via on the pcb but I can't figure where is going too because is routed internally.
 

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N4CR

Supreme [H]ardness
Joined
Oct 17, 2011
Messages
4,765
Does top left 8x pin have solder or is it just a trick of shadowing?
 
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albobbyD

n00b
Joined
Mar 3, 2021
Messages
7
It has. Is just a shadow in the picture. I will try to have a look where that trace goes. It should definitely go to the gate of a transistor.
 

albobbyD

n00b
Joined
Mar 3, 2021
Messages
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I've just sorted it out. A trace was damaged just before a via pad near Q1. Hard to spot even with 20X lenses on my microscope. Thank you very much.
 

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