Measuring Voltages on the Card itself - Outside the motherboard.

[yd1]

in continue to this post page 47 & 48
where @MrGenius was helping me mod the bios.
https://www.techpowerup.com/forums/...or-radeon-hd-7000-series-cards.189089/page-48

what im trying to do is to verify the card voltages ON the GPU itself,
after modding the BIOS with VBE7 & UV the card idle/desktop state.
the BIOS did seamed to accept the new UV, but all software show no voltage changes of the specific moded idle/desktop state.
so im trying to measures actual voltage on the card itself, to verify BIOS UV.

And until i feel confident enough doing this on my 7970.
im going to do that outside my motherboard & precious components on my old 4870 & external PSU.

So, i got to the point of jumping the PSU & making sure it's working but no power was getting to the card.

MrGenius suggested to input 12v to PCIe pin's, but im not sure how to go about that..


best way i assume was to find a 12v on the 24pin connector of the PSU, (poking them with multi-meter should be safe right?)
but how to actually connect it to the PCIe pins?
is it possible to soldier a wire to the 2nd or 3rd pin (without bridging pins together.)

any thought?

 

[DR4G00N]

You need to provide +12V & +3.3V to the PCIe connector as well as any +12V 6/8 Pin connectors.
Best bet is to buy a cheap PCIe riser and just modify it for this purpose.

I don't see the point though, why not just measure the voltage while it's inside the system?

 

[MrGenius]

I forgot about the +3.3V. I guess you'd need that hooked up too. Anyway, you don't need to worry about bridging power pins(as long as they're the same voltage). And soldering might be a bit more than necessary. You could probably get away with clamping some wires on the pins with clothes pins(or something similar, maybe some alligator clips if you're careful with them).

 

[silentbogo]

the BIOS did seamed to accept the new UV, but all software show no voltage changes of the specific moded idle/desktop state.
so im trying to measures actual voltage on the card itself, to verify BIOS UV.

Just get a riser. You need all startup voltages to be present on the card, and even if you do supply it manually, it might still not pass the startup sequence and won't get your VCORE and VMEM.
If you don't wanna spend money on a rizer, then at least solder a wire to one of the chokes on GPU VRM and once the PC is powered on - measure it relatively to chassis (just make sure that your "testpoint" wire isn't touching anything, and that you've soldered it on firmly)

Simply supplying some voltages to the card does not mean that the card will start.

 

[yd1]

f you don't wanna spend money on a rizer, then at least solder a wire to one of the chokes on GPU VRM and once the PC is powered on - measure it relatively to chassis (just make sure that your "testpoint" wire isn't touching anything, and that you've soldered it on firmly)

i think its the best idea so far.
(assuming i can actually solder it property & know where to exactly)
1. no risk of multi-meter probe slippage..
2. and it can be done comfortably on my desk outside the case.

ok i still think im going to attempt it first on the 4870 before the 7970.
but i need to take some pictures & hopfully you guys can direct me where to connect the wire.

 

[silentbogo]

but i need to take some pictures & hopfully you guys can direct me where to connect the wire.

Just find the choke that's responsible for GPU core voltage. I've marked those for you on the photo.
Soldering wire is going to be hard, since you have to deal with lead-free solder and a big-ass GPU with high thermal capacity. Even my soldering station can't handle it that well (gonna upgrade to a decent 90W inductive iron soon).

 

[MrGenius]

@silentbogo are you mocking me? Because I think it's hilarious!

Nice try though...

 

[DR4G00N]

(gonna upgrade to a decent 90W inductive iron soon).

Get a 150W iron, it'll work a lot nicer. Speaking from experience with modifying the crap out of graphics cards.

The chokes on the 7970 Ref PCB are an SMD type so you can't use them to measure from the back. just measure from the capacitor legs I outlined. The legs with square pads are the VGPU output.

 

[yd1]

deal with lead-free solder and a big-ass GPU with high thermal capacity. Even my soldering station can't handle it that well (gonna upgrade to a decent 90W inductive iron soon).

that's well above my skill & equipment capabilities..
even if i go the raiser route, there's no way for me to test the idle state (300Mhz ) UV which
im interested in... right? if it work it will go to full core voltage i assume?

i took a second look on my 7970 in case to see if there's a point i can safely measure.
but it's just too risky especially due to my analog multi-meter that has no recording or peak memory function..
the 2 contacts are so close ..




last idea before i face my limitation and gracefully give this up?

 

[silentbogo]

last idea before i face my limitation and gracefully give this up?

... or put your trust into software readings

 

[yd1]

The chokes on the 7970 Ref PCB are an SMD type so you can't use them to measure from the back. just measure from the capacitor legs I outlined. The legs with square pads are the VGPU output.

the square pad is the one i need to check?