Question My PSU 24 pin connector got burnt without reason

flagmonkey47

Member
Apr 24, 2019
49
1
16
I have a CX 450 PSU which I bought in july 2019. My specs are-
Ryzen 3 1200
AB350M-GAMING3
RX 460 4GB
16GB DDR4
Due to some issue with my motherboard (not related to power or the connectors) I go my motherboard replaced with a refurbished one. My PSU wass working fine till then. After a month of usage my PC started having problems. It restarted whenever I played any game. I checked the 24 pin connectors and two of its pins were burnt. It did not melt even slightly but it had a blackish look. I monitored voltages using HWinfo and they were dropping to 10V. So my question is how did my PSU connector got burnt. Could it be due to my fault that I didn't connect the 24 pin connector tightly or is it the motherboard which burnt my PSU?? Also I got the refurbished motherboard checked by the Gigabyte service center and they said it had no problems.
 

flagmonkey47

Member
Apr 24, 2019
49
1
16
Your "refurbished" motherboard is bad. Get it replaced.
Can I test it if it is bad or not ? The people at service center said that they tested it for 6 hours and they didn't find anything wrong. Please guide. I am ready to replace my board if it is a risk for my components.
 

serpretetsky

Senior member
Jan 7, 2012
620
18
81
Which pins are burned? Photo? Is the 8pin EPS12V cpu power connected on the motherboard along with the 24pin?
Check if the pins on the power connectors (mobo and PSU) look like they have any corrosion.
 

flagmonkey47

Member
Apr 24, 2019
49
1
16
Which pins are burned? Photo? Is the 8pin EPS12V cpu power connected on the motherboard along with the 24pin?
Check if the pins on the power connectors (mobo and PSU) look like they have any corrosion.
I used a torch to see if the pins on motherboard were corroded or not. I saw that the two pins burnt did not reflect light properly as the other pins did. For PSU I have this picture-

Pins 2,3 from top are burnt. I did not understand your question about the 8pin CPU connector and 24 pin connector. Aren't both of them supposed to be connected?
 

serpretetsky

Senior member
Jan 7, 2012
620
18
81
Those are the 2 +12V lines on the 24pin, which is kind of expected, they are the high current lines, all the other lines don't draw that much current.

Yes, your 8pin should be connected, i was just making sure.

If the 8pin had proper contact from the PSU internal +12V and GND and into the motherboard ground and power planes I doubt you would see those pins heating up. So my bet is the 8pin is not making proper contact SOMEWHERE (don't know if its on the mobo or in the PSU, it could be a poor solder job somehwere? or connector not plugged in all the way?).

Good luck.
 

flagmonkey47

Member
Apr 24, 2019
49
1
16
Those are the 2 +12V lines on the 24pin, which is kind of expected, they are the high current lines, all the other lines don't draw that much current.

Yes, your 8pin should be connected, i was just making sure.

If the 8pin had proper contact from the PSU internal +12V and GND and into the motherboard ground and power planes I doubt you would see those pins heating up. So my bet is the 8pin is not making proper contact SOMEWHERE (don't know if its on the mobo or in the PSU, it could be a poor solder job somehwere? or connector not plugged in all the way?).

Good luck.
But my question is should I further use this board or will it damage my components or supply.
 

serpretetsky

Senior member
Jan 7, 2012
620
18
81
But my question is should I further use this board or will it damage my components or supply.
Not sure. Undervoltage might damage some components, maybe somebody else here will know. The PSU is probably not going to be damaged (well... except the connector if it melts/burns). But the PSU could be damaged if its being overloaded for long periods of time for some reason by the motherboard.
 

jonnyGURU

Moderator <BR> Power Supplies
Moderator
Oct 30, 1999
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But my question is should I further use this board or will it damage my components or supply.
You need to see if you can clean the burns.

The +12V lines on the 24-pin should not have much load on them.

That RX 460 doesn't have PCIe connectors on it, right? So it has to draw all of its power from the slot.

What are you using the PC for? Are you overclocking the GPU at all?
 

flagmonkey47

Member
Apr 24, 2019
49
1
16
You need to see if you can clean the burns.

The +12V lines on the 24-pin should not have much load on them.

That RX 460 doesn't have PCIe connectors on it, right? So it has to draw all of its power from the slot.

What are you using the PC for? Are you overclocking the GPU at all?
I am not overclocking anything. My GPU does not have the 6 pin connector. I cleaned the pins with isopropyl alcohol but the burns didn't go. I will see if I can get the connector replaced by some local shop.
 
Last edited:

jonnyGURU

Moderator <BR> Power Supplies
Moderator
Oct 30, 1999
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I am not overclocking anything. My GPU does not have the 6 pin connector. I cleaned the pins with isopropyl alcohol but the burns didn't go. I will see if I can get the connector replaced by some local shop.
I worry if your graphics card is pulling too much power to the 24-pin.

I'm not sure the 8-pin connector on your motherboards provides power to the PCIe slots or just the CPU.
 

flagmonkey47

Member
Apr 24, 2019
49
1
16
I worry if your graphics card is pulling too much power to the 24-pin.

I'm not sure the 8-pin connector on your motherboards provides power to the PCIe slots or just the CPU.
The motherboard and PSU were working fine before. I think my problem will be solved after I get the connector replaced and if it doesn't I will change the board. I have already sent my PSU for replacement.
 

Micrornd

Golden Member
Mar 2, 2013
1,064
102
106
I used a torch to see if the pins on motherboard were corroded or not. I saw that the two pins burnt did not reflect light properly as the other pins did. For PSU I have this picture-

Pins 2,3 from top are burnt. I did not understand your question about the 8pin CPU connector and 24 pin connector. Aren't both of them supposed to be connected?
In the picture you provided, those 2 females (Pins 2, 3 from top) do not appear to be fully seated in the connector (notice they appear recessed compared to the others)
If they move backward in the connector when you insert it into the MB, while a connection will be made, it won't be a good one.
Try pushing those 2 wires further into the connector, they should lock into place and stay (flush like the others), you should not be able to pull them backward (or out).
If they won't stay in place properly, a local shop should be able to fix them.
 

pcgeek11

Lifer
Jun 12, 2005
16,938
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It would be better to understand that a loose fitting pin to terminal is acting like a heater due to increased resistance. A heater is just a high resistance in a wire.

As I understand it the heating is just in the connector and not the entire wire. ( correct me if I'm wrong). If it was a high current draw the entire length of the wire would show signs of overheating.
 

flagmonkey47

Member
Apr 24, 2019
49
1
16
In the picture you provided, those 2 females (Pins 2, 3 from top) do not appear to be fully seated in the connector (notice they appear recessed compared to the others)
If they move backward in the connector when you insert it into the MB, while a connection will be made, it won't be a good one.
Try pushing those 2 wires further into the connector, they should lock into place and stay (flush like the others), you should not be able to pull them backward (or out).
If they won't stay in place properly, a local shop should be able to fix them.
Could it be that the refurbished motherboard connector lost contact due to wear and tear done by excessive use before the service center gave it to me? If I decide to get it replaced (the connector) how easy is it?
 

Micrornd

Golden Member
Mar 2, 2013
1,064
102
106
It would be better to understand that a loose fitting pin to terminal is acting like a heater due to increased resistance. A heater is just a high resistance in a wire.

As I understand it the heating is just in the connector and not the entire wire. ( correct me if I'm wrong). If it was a high current draw the entire length of the wire would show signs of overheating.
Heating will be the highest at the point of highest resistance, in this case that would be at any loose/not fully made contacts. Remember this isn't nichrome (heater) wire, where the wire itself has a higher resistance that the connectors.
But, yes, if allowed to continue long enough and at a high enough current draw, the wire itself would show damage to the insulation.
Also notice how large the gaps are on those 2 females where they come together at the top compared to the other females in the connector. Last time I looked, all the male pins on a 24pin are the same size, so any females that don't grip the male pins tightly add some resistance and could be a source of heating.
Anyway, it's all speculation, without having the board to physically test it's just guessing, and your guess is as good as mine, maybe better :)
 

Micrornd

Golden Member
Mar 2, 2013
1,064
102
106
Could it be that the refurbished motherboard connector lost contact due to wear and tear done by excessive use before the service center gave it to me? If I decide to get it replaced (the connector) how easy is it?
Not very likely.
Best to just let a qualified shop check it out and go from there. ;)
 

mindless1

Diamond Member
Aug 11, 2001
5,155
383
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Could it be that the refurbished motherboard connector lost contact due to wear and tear done by excessive use before the service center gave it to me? If I decide to get it replaced (the connector) how easy is it?
This depends on your means, what tools you have and your skill level, experience doing it.

A competent tech with a hot air rework station, could blast hot air on the connector and get it off in a minute, use desoldering braid or a solder sucker to clean out the holes in another few minutes, slip the new connector in and solder it in another couple minutes, so it's an under 10 minute repair.

If you lack a hot air rework station to heat all the pins simultaneously, I wouldn't even bother trying. It IS possible, basically you would cut up the plastic connector shell or grip each pin individually with pliers to pull it out when the heat not only melts the solder but also the tab in the connector that is holding it together, but that may subject the PCB to excessive heat. It is definitely not ideal.

I suppose I would start by inspecting the connector pins to see if they look centered, if the connector shell looks intact rather than melted, and if the pins are shiny. If all that is true then I'd try a different PSU. I'd also monitor the motherboard voltage readings to see how low they dip under load. If the connector is causing a resistance drop, it should increase over the value measured at the back of the connector, the higher the load is on each voltage rail. Granted, a little extra drop under load is normal, but enough to heat it up is something you should notice.
 

jonnyGURU

Moderator <BR> Power Supplies
Moderator
Oct 30, 1999
11,778
61
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Could it be that the refurbished motherboard connector lost contact due to wear and tear done by excessive use before the service center gave it to me?
That's a good thought.

I know at the PSU factories, they tend to use the same cable set to test fully modular PSUs on the line. But once the cables are used X number of times, they discard them because they become "worn out".
 

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