EVGA GTX 1060 1V Missing (Pascal)

[4TMtv]

I currently am working on an EVGA 1060. All voltages are present when the card is powered on except I'm missing 1V.

The buck converter, uP1728Q is getting power to it.
I'm getting
VDD- 5V
VIn - 3.3v
En - 1.76v
Mode - 5v
Lx - 0v.

It appears no power is leaving the controller. What would be the cause of this. Could it be the FB circuit? The buck converter itself is brand new as the original was replaced.

Following the traces in the picture, is the FB circuit the 3 resistors and 2 caps to the top right of the chip?

 

[RazorWind]

What is the resistance to ground on LX?

 

[4TMtv]

What is the resistance to ground on LX?

161 Ohms

 

[RazorWind]

How did you replace that IC? Did you just fire up the hot air station to 900C and YOLO it, or did you use a preheater? It's possible you killed the replacement in the process of installing it. I can say this because I've done it. Many times. Like a jackass.

Now that I look at it again, the EN signal looks a little low. If you look at the datasheet, it says that it's supposed to be in the range of 2.6 to 5.5V. What I might do is remove the IC from the board again, and check what voltage I have at that pin. if you have something like 3.3V, then the problem was your IC, and you know to install a new one. If you have 1.76V still, then you have a short elsewhere, and you need to figure out where that EN signal comes from.

 

[4TMtv]

How did you replace that IC? Did you just fire up the hot air station to 900C and YOLO it, or did you use a preheater? It's possible you killed the replacement in the process of installing it. I can say this because I've done it. Many times. Like a jackass.

Now that I look at it again, the EN signal looks a little low. If you look at the datasheet, it says that it's supposed to be in the range of 2.6 to 5.5V. What I might do is remove the IC from the board again, and check what voltage I have at that pin. if you have something like 3.3V, then the problem was your IC, and you know to install a new one. If you have 1.76V still, then you have a short elsewhere, and you need to figure out where that EN signal comes from.

Appreciate the input, fortunately have another IC I can use Incase I did fry it. I typically preheat the board before blasting it with hot air. But I'll reply with the voltage on the EN signal after I remove the IC again

 

[RazorWind]

Appreciate the input, fortunately have another IC I can use Incase I did fry it. I typically preheat the board before blasting it with hot air. But I'll reply with the voltage on the EN signal after I remove the IC again

You might also check what the resistance to ground is. It should be pretty high. If you have a low value, and especially if it's 160 ohms (just like the output!) that's a clue that you have a short in the IC.

 

[4TMtv]

How did you replace that IC? Did you just fire up the hot air station to 900C and YOLO it, or did you use a preheater? It's possible you killed the replacement in the process of installing it. I can say this because I've done it. Many times. Like a jackass.

Now that I look at it again, the EN signal looks a little low. If you look at the datasheet, it says that it's supposed to be in the range of 2.6 to 5.5V. What I might do is remove the IC from the board again, and check what voltage I have at that pin. if you have something like 3.3V, then the problem was your IC, and you know to install a new one. If you have 1.76V still, then you have a short elsewhere, and you need to figure out where that EN signal comes from.

After testing with the IC removed, I'm still getting 1.76v to the EN pin. Is finding the fault on this line going to come down to checking with continuity and visual aid? I'm not aware of any schematics available

 

[4TMtv]

You might also check what the resistance to ground is. It should be pretty high. If you have a low value, and especially if it's 160 ohms (just like the output!) that's a clue that you have a short in the IC.

I forgot to check resistance to ground before removing the chip. After removing the chip the resistance to ground reads about 1 Ohm.

 

[RazorWind]

Ok, so, good news is that your IC is probably OK. Bad news is that you have a short somewhere between the enable pin and whatever the source for that is.

What resistance to ground do you have on each of the other power rails on the board?

12V inputs (all two or three)
3.3V input (at the slot)
Probably a 5V rail
1.8V?

Look for other buck converters and see if you can figure out which one it is that's supposed to supply that enable voltage. If I had to guess, I'd say it's either the 3.3V or a 5V rail.

 

[4TMtv]

Ok, so, good news is that your IC is probably OK. Bad news is that you have a short somewhere between the enable pin and whatever the source for that is.

What resistance to ground do you have on each of the other power rails on the board?

12V inputs (all two or three)
3.3V input (at the slot)
Probably a 5V rail
1.8V?

Look for other buck converters and see if you can figure out which one it is that's supposed to supply that enable voltage. If I had to guess, I'd say it's either the 3.3V or a 5V rail.

Attached are some photos of the card with measurements as well as the points they were measured. Being honest I wrote 1.0Ω @ 200M because I know the max resistance is 200million but my brain couldn't process if i was getting a 1 million ohm reading or 100million. To find the converter that supplies the enable voltage I don't have a schematic, can I use continuity mode to find where it connects to and check that way?

At the slot the 3.3v line has a resistance reading of 1.0Ω with 200M resistance setting

 

[4TMtv]

Ok, so, good news is that your IC is probably OK. Bad news is that you have a short somewhere between the enable pin and whatever the source for that is.

What resistance to ground do you have on each of the other power rails on the board?

12V inputs (all two or three)
3.3V input (at the slot)
Probably a 5V rail
1.8V?

Look for other buck converters and see if you can figure out which one it is that's supposed to supply that enable voltage. If I had to guess, I'd say it's either the 3.3V or a 5V rail.

Furthermore, I'm not sure if it matters. However, I do not get any voltage to the feedback input pin on uP1728Q. I understand the enable voltage is low but also reading the datasheet that if FB is under 0.26v it will use under-voltage protection to shut off the ic. Do I need the enable signal before I will get any voltage on the FB pin?

 

[RazorWind]

I wouldn't worry about the FB pin. You have a 1.0 ohm short to ground on the enable pin, which is for sure a show-stopper.

You can try to use continuity mode to figure out where the EN traces go, but because it's shorted to ground, you'll likely find that continuity mode tells you it goes almost everywhere. Instead, use actual ohms mode, and look for somewhere that has 0.0 ohms to that pad.

In your photos, you show that you have a 1.0 ohm short on the 8 pin 12V input. Are you sure about that? You'd most likely trip the over current protection in the power supply if you really had a short on the 12V input rail.

 

[4TMtv]

I wouldn't worry about the FB pin. You have a 1.0 ohm short to ground on the enable pin, which is for sure a show-stopper.

You can try to use continuity mode to figure out where the EN traces go, but because it's shorted to ground, you'll likely find that continuity mode tells you it goes almost everywhere. Instead, use actual ohms mode, and look for somewhere that has 0.0 ohms to that pad.

In your photos, you show that you have a 1.0 ohm short on the 8 pin 12V input. Are you sure about that? You'd most likely trip the over current protection in the power supply if you really had a short on the 12V input rail.

I don't believe it's a short because my multimeter meter was set to the highest resistance setting of 200M and I actually got a reading. I know when the card is powered on I get 12v on the same measuring point. I also get 12v in numerous other locations that it's expected to be. I do just have a cheaper multimeter and need to get a higher quality one for this new repair skill I'm learning.

Would it be possible to use voltage injection to find the short in the EN pin? I have a good quality DC Bench PSU that could be used.

 

[RazorWind]

You can totally try to use current injection, but you obviously want to be careful about exactly where you inject it. The trace for that enable pad is probably pretty small, and you run the risk of damaging it if you try to pass a zillion amps through it. If you can find a larger pad that is connected directly to it that you can inject current into, you'll have better luck finding the short.

Edit: First, I would try to use regular-ass ohms mode (NOT continuity mode) to figure out where the source for that EN signal is, though. That will help you narrow down what's in short, and because the resistance is so low, there's a pretty good chance that you won't have much luck with current injection, especially if you have no idea as to where to look.

 

[4TMtv]

You can totally try to use current injection, but you obviously want to be careful about exactly where you inject it. The trace for that enable pad is probably pretty small, and you run the risk of damaging it if you try to pass a zillion amps through it. If you can find a larger pad that is connected directly to it that you can inject current into, you'll have better luck finding the short.

Edit: First, I would try to use regular-ass ohms mode (NOT continuity mode) to figure out where the source for that EN signal is, though. That will help you narrow down what's in short, and because the resistance is so low, there's a pretty good chance that you won't have much luck with current injection, especially if you have no idea as to where to look.

I'm not sure why I had informed you the EN pin was showing no resistance to ground. After walking away from the card for a bit I have returned to it and am just going to restate what I know for myself and hopefully as to not give you wrong information again.
I'm going to approach this as if it's a new card
In front of me is an EVGA GTX 1060.
At the moment these are the known values on the power rails for resistance to ground:
12V- 1.7MΩ by the 6 pin, 4.5MΩ by the pcie slot, 1.75MΩ near the top left of the card (on 2k, 20k, 200k the multimeter showed OL)
5V- 62Ω
1.8V- 480Ω
3.3- 83kΩ

Since there appeared to be no shorts to ground on the device I plugged it into my bench setup and these are the voltages I have present:
12V - Present in all 3 locations measured for resistance
5V - Present
1.8V - Present
3.3V - Present
1V - not present

The initial suspect was uP1728Q and this was probed to check the voltages getting to the converter
FB - 0v
VDD - 5V
VIn - 3.3v
GND
GND
EN - 1.76v
POK - 0.68v
Mode - 5v
Lx - 0v

There is no voltage leaving the converter. The resistance to ground on the inductor is 160Ω with or without the IC on the board.

To eliminate the IC being the issue it was removed and there was no change in the voltages getting to the pins of the IC, which also means no power is still getting out.
As discovered, the enable voltage does seem low, however it is not shorting to ground.
So the card seems to be getting power overall, there is no image being displayed though. There is no voltage on the Vcore inductors or memory inductors when the card is powered on. But 12v is showing up on the caps in front of the MOSFETs..
I'm sorry if any missing information shines new light on what's wrong. I appreciate all the help truly as this is a skill I'm trying to get better at

 

[RazorWind]

What is the actual resistance to ground, in ohms, on the uP1728Q EN pin?

You say it's not shorted, but the voltage you're seeing there is low, according to the datasheet. It should be something like 2.5-5.5V. I would guess it's actually supposed to be 3.3V, but 5V is a possibility too.

One possibility is that there's a little transistor somewhere that gets 1.8V (from the 1.8V rail) on the gate pin (or base) and passes through 3.3V. If that had failed, it's possible for it to just have 1.8V passing through it.

 

[4TMtv]

What is the actual resistance to ground, in ohms, on the uP1728Q EN pin?

You say it's not shorted, but the voltage you're seeing there is low, according to the datasheet. It should be something like 2.5-5.5V. I would guess it's actually supposed to be 3.3V, but 5V is a possibility too.

One possibility is that there's a little transistor somewhere that gets 1.8V (from the 1.8V rail) on the gate pin (or base) and passes through 3.3V. If that had failed, it's possible for it to just have 1.8V passing through it.

I'll have to check tomorrow when I have the card for exact resistance. The datasheet I looked at (https://datasheetspdf.com/pdf/1259305/uPISemiconductor/uP1728/1)
Chip Enable/Disable and Soft-Start

"The uP1728 features an EN pin for enable/disable control
of the output voltage. Pulling the EN pin lower than 0.4V
shuts down the uP1728 and reduces its quiescent current
lower than 1uA. In the shutdown mode, both upper and
lower switches are turned off. Pulling EN pin higher than
1.5V enables the uP1728. Once the chip is enabled, the
VDD POR is granted. The internal soft-start capacitor
becomes charged and generates a linear ramping up
voltage across the capacitor. This voltage clamps the
voltage at the FB pin causing PWM pulse width to increase
slowly and in turn reduce the output surge current. The
internal 0.6V reference takes over the loop control once
the internal ramping-up voltage becomes higher than 0.6V.
PWM"

With this in mind it seems like 1.8v is fine or am I missing something? But as stated I'll get an exact resistance reading tomorrow.

 

[4TMtv]

What is the actual resistance to ground, in ohms, on the uP1728Q EN pin?

You say it's not shorted, but the voltage you're seeing there is low, according to the datasheet. It should be something like 2.5-5.5V. I would guess it's actually supposed to be 3.3V, but 5V is a possibility too.

One possibility is that there's a little transistor somewhere that gets 1.8V (from the 1.8V rail) on the gate pin (or base) and passes through 3.3V. If that had failed, it's possible for it to just have 1.8V passing through it.

Okay after further learning, reading, and testing. I'm missing vcore voltage. When checking uP9509 (Vcore controller) I'm only getting 0.46v on Vcc. I'm only getting 1.4v on the EN pin for it.
This explains why I'm not getting Voltage on Vmem and PEX because of the power sequence the cards follow. Since Vcore is not switching on the other two aren't. I'm currently trying to figure out why the Vcc is not getting 5v. EN should also be getting 3v. Would it be correct in stating both circuits have an issue or would solving the Vcc circuit issue possibly solve the EN pin low voltage?

 

[RazorWind]

Ok, I think you need to stop and take a step back. Here's what you do.

Make a list of every buck converter and voltage that's expected on the card. Check which ones are and are not running. Don't worry about why right now, just make a note of which ones are and aren't present.

Take the card back apart and check the resistance to ground on each converter. Compare these values to the known good values. Look for any that are significantly lower than expected. This will tell you if you have a short to ground on any of them, which is the most common reason for them not to work.

Then, and only then, once you're sure you have correct and accurate resistance measurements on each rail, should you start worrying about why each one isn't working. Currently, you're chasing your tail because you're not even sure that the resistance measurements you're taking are accurate.

Finally, VCore is usually the last to start. If it's not running on your card, it's because one of the others isn't, and it's waiting for that one.

 

[4TMtv]

Ok, I think you need to stop and take a step back. Here's what you do.

Make a list of every buck converter and voltage that's expected on the card. Check which ones are and are not running. Don't worry about why right now, just make a note of which ones are and aren't present.

Take the card back apart and check the resistance to ground on each converter. Compare these values to the known good values. Look for any that are significantly lower than expected. This will tell you if you have a short to ground on any of them, which is the most common reason for them not to work.

Then, and only then, once you're sure you have correct and accurate resistance measurements on each rail, should you start worrying about why each one isn't working. Currently, you're chasing your tail because you're not even sure that the resistance measurements you're taking are accurate.

Finally, VCore is usually the last to start. If it's not running on your card, it's because one of the others isn't, and it's waiting for that one.

Okay went through and pulled up several datasheets for chips on the board. As well as double checked resistances on rails and voltages at different points in the card. I'm uploading the photos so you can see everything labeled. I do want to apologize as this is my first GPU I'm attempting to repair so any material you might have for learning is greatly appreciated. I'll even pay ya because you've been so helpful with such a noob.

EXPECTED VOLTAGE is outside the parenthesis according to datasheets. The MEASURED values are located inside the parenthesis, all resistance readings are readings with resistance to ground.

I did begin to realize I was chasing my own tail as I read more material last night. From what I understand after reading is: The order in which they turn on in most pascal GPUs is as follows: 5V→ 1.8V→ VCore→ VMem/PEX. Since I have 5V and 1.8V present that should mean VCore is next right? Also I'm pulling this information from (https://repair.wiki/w/Nvidia_Pascal..._.285V.2C_1.8V.2C_VCore.2C_VMem.2C_and_PEX.29)

I probably missed looking up a converter somewhere but I found datasheets for all the ones in the photo. Again, I appreciate all the help. When it comes to known good values for resistance to ground I have no actual reference point for this