Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting Power Supplies and Power Supply Design
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 04-09-2021, 02:21 AM   #1
Guilty_2121
Member
 
Join Date: Jan 2021
City & State: Osmaniye
My Country: Türkiye
I'm a: Knowledge Seeker
Posts: 27
Default cooler master rs-750 load problem

Hi everyone,
my power supply shuts off under load, starts with out problem, the i tried to play game or benchmark, pc shuts off. I check the caps they looks good and looks like no weak solder. what shout i suspect?
model: cooler master rs-750-amaa-b1
Guilty_2121 is offline   Reply With Quote
Old 04-09-2021, 04:03 AM   #2
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 25,521
Default Re: cooler master rs-750 load problem

caps still - they need to be removed and metered with an esr meter
stj is offline   Reply With Quote
Old 04-10-2021, 10:56 PM   #3
momaka
master hoarder
 
momaka's Avatar
 
Join Date: May 2008
City & State: VA (NoVA)
My Country: U.S.A.
Line Voltage: 120 VAC, 60 Hz
I'm a: Hobbyist Tech
Posts: 10,602
Default Re: cooler master rs-750 load problem

Can you post some pictures here of the internals of the power supply? That way we can see what you have.

Also, did you try your PC with another PSU and confirm the system can stay turned On under heavy load? Just asking to make sure we are not troubleshooting an issue that may not exist (i.e. possibly having the system be faulty and not the PSU.)
momaka is offline   Reply With Quote
Old 04-11-2021, 04:47 AM   #4
Guilty_2121
Member
 
Join Date: Jan 2021
City & State: Osmaniye
My Country: Türkiye
I'm a: Knowledge Seeker
Posts: 27
Default Re: cooler master rs-750 load problem

Quote:
Originally Posted by momaka View Post
Can you post some pictures here of the internals of the power supply? That way we can see what you have.

Also, did you try your PC with another PSU and confirm the system can stay turned On under heavy load? Just asking to make sure we are not troubleshooting an issue that may not exist (i.e. possibly having the system be faulty and not the PSU.)
Yes, i take my friends 600w and try for 3 days and everything is good on PC.
back side is looks ok. no weak solder.
Guilty_2121 is offline   Reply With Quote
Old 04-11-2021, 08:15 PM   #5
momaka
master hoarder
 
momaka's Avatar
 
Join Date: May 2008
City & State: VA (NoVA)
My Country: U.S.A.
Line Voltage: 120 VAC, 60 Hz
I'm a: Hobbyist Tech
Posts: 10,602
Default Re: cooler master rs-750 load problem

Quote:
Originally Posted by Guilty_2121 View Post
Yes, i take my friends 600w and try for 3 days and everything is good on PC.
Ok, good to know. So it likely is the PSU, then.

Based on the pictures you provided, I see a lot of CapXon capacitors. Generally, CapXon does show signs when it goes bad (bulging, leaking, and etc.) But because it's a very crappy brand, it really is hard to know if any of those caps are actually good or not without pulling them out of the PSU and measuring them with an ESR meter. If you have an ESR meter (one of those cheap GM328 multi-function testers will do - they cost about $15) or if you have a friend / know a repair shop that has one, then it would be best to remove each cap and test it. Capacitance should be within +/-20% of what is printed on each cap. And ESR should be less than 0.1 Ohms for most of the caps (the really small 5x11 caps may show up to 2-3 Ohms, which isn't considered terrible.)

Again, because none of the caps look bad, my suggestion would be to start with the small ones seen in this picture, as they are most prone to drying out and not showing visible signs of failure when they do go bad:
https://www.badcaps.net/forum/attach...5&d=1618137991

If they test OK, remove and test the two big caps shown here:
https://www.badcaps.net/forum/attach...3&d=1618137991

And if those test OK, then check the rest of the secondary-side electrolytic caps, which can be seen here:
https://www.badcaps.net/forum/attach...7&d=1618137991

Also, post a clear-focused picture of the under-side of the PSU, if possible. I would like to see if anyone of us can spot anything on there that perhaps may have gotten overlooked.

Last edited by momaka; 04-11-2021 at 08:20 PM..
momaka is offline   Reply With Quote
Old 04-12-2021, 06:47 AM   #6
Guilty_2121
Member
 
Join Date: Jan 2021
City & State: Osmaniye
My Country: Türkiye
I'm a: Knowledge Seeker
Posts: 27
Default Re: cooler master rs-750 load problem

Quote:
Originally Posted by momaka View Post
Ok, good to know. So it likely is the PSU, then.

Based on the pictures you provided, I see a lot of CapXon capacitors. Generally, CapXon does show signs when it goes bad (bulging, leaking, and etc.) But because it's a very crappy brand, it really is hard to know if any of those caps are actually good or not without pulling them out of the PSU and measuring them with an ESR meter. If you have an ESR meter (one of those cheap GM328 multi-function testers will do - they cost about $15) or if you have a friend / know a repair shop that has one, then it would be best to remove each cap and test it. Capacitance should be within +/-20% of what is printed on each cap. And ESR should be less than 0.1 Ohms for most of the caps (the really small 5x11 caps may show up to 2-3 Ohms, which isn't considered terrible.)

Again, because none of the caps look bad, my suggestion would be to start with the small ones seen in this picture, as they are most prone to drying out and not showing visible signs of failure when they do go bad:
https://www.badcaps.net/forum/attach...5&d=1618137991

If they test OK, remove and test the two big caps shown here:
https://www.badcaps.net/forum/attach...3&d=1618137991

And if those test OK, then check the rest of the secondary-side electrolytic caps, which can be seen here:
https://www.badcaps.net/forum/attach...7&d=1618137991

Also, post a clear-focused picture of the under-side of the PSU, if possible. I would like to see if anyone of us can spot anything on there that perhaps may have gotten overlooked.
At first thank you so much master. And here is the pictures you want.
I like to fix my thing and i can spend several hours on try. But this is a little hard for me but i will try my best and tell the what happen
Guilty_2121 is offline   Reply With Quote
Old 04-20-2021, 10:52 PM   #7
momaka
master hoarder
 
momaka's Avatar
 
Join Date: May 2008
City & State: VA (NoVA)
My Country: U.S.A.
Line Voltage: 120 VAC, 60 Hz
I'm a: Hobbyist Tech
Posts: 10,602
Default Re: cooler master rs-750 load problem

Well, just to say here that I'm battling the same (or very very similar issue) with a Rosewill Valens 600 PSU. The PSU itself is quite different from this one, but it's doing something similar: it will turn On and run fine without a load (or with a very very light load, like an HDD or two) with all voltages in spec. But the moment I try to run any motherboard with it or heavier load, it turns Off. So if I find anything that might be related, I'll report back too. I haven't had a chance to check the caps yet, but I suspect that the issue might be either a small "startup/run" cap somewhere gone bad or perhaps the APFC / main input filter cap gone/going bad.
momaka is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums © 2003 - 2021
Powered by vBulletin ®
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 09:17 PM.
Did you find this forum helpful?