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
Old 08-11-2020, 04:59 PM   #1
New Member
Join Date: Aug 2020
City & State: Singapore
My Country: Singapore
I'm a: Knowledge Seeker
Posts: 2
Default Need Help Thermaltake Litepower 500W Problem

Hello everyone,
PSU: Thermaltake Litepower 500W Model: LT-500AL2NC
PCB: G08-CGPA462-PA00 Rev:A
I have this PSU installed in my PC for several years.
The problem is one day my PC cannot detect an external HDD so i think maybe the PSU caps already bad.
So i decided to open the case and found some of the secondary caps already bulging.
Then i recapping all the caps except the primary one (because i tested it with an esr meter and its still good) and i already tested all the new caps too before i soldered them.
After that the psu is good and my pc can detect my external HDD.
But 1-2 days later, when i using my pc suddenly i hear a clicking sound from the psu several times and then my PC turned off (about 5-10 min after the sound).
Then i removed the psu and tested it with psu tester and a light bulb (100W) in series with the AC mains.
Guess what, the light bulb shine brightly (something shorted!) and the psu fan spinning and i got all the voltage readings correct but only for a moment (about 1 min) after that all the voltage readings become 0 and only the 5vsb output remains.
So i open the psu again and start looking for the problem.
I tested the mains rectifier and all the diodes and it's all good.
I tested the filter safety caps OK, ZNR OK, Thermistor OK, Resistors in primary side OK.
I removed all the heatsink,tested the components and found the problem.
One of the 13N50 Mosfet in the middle heatsink is shorted and the PFR30L45CT diode in the secondary heatsink also shorted.
Then i decided to replace them but i cannot find the exact same parts in the local electronics store.
So i looked for similar parts and replaced all of the 13N50 with 15N50 and replaced PFR30L45CT with MBR30100PT.
After soldered all the parts and cleaning the PCB, i tested it again.
And now the AC mains light bulb is only flashed for 1 sec (charging the primary caps) and then turned off.
BUT, i still only got 5vsb readings on my psu tester.
So i decided to open the psu again (and again) looking for another problem.
I removed the KN2222A,KN2907A,TL431K,2SC1384L and found no problem.
I removed the PC817 opto and found one of them is bad, replaced all 3 of them with a new one.
But still no luck, all i got is only 5vsb output.
So, i wanna ask everyone here for help and maybe one of you have similar psu and know the problem.
I'm not an expert at electronics but i want to learn more about it.
Thanks in advance for your help.
Attached Images
File Type: jpg 1.jpg (903.9 KB, 15 views)
File Type: jpg 2.jpg (784.1 KB, 6 views)
File Type: jpg 3.jpg (847.8 KB, 5 views)
File Type: jpg 4.jpg (848.3 KB, 4 views)
File Type: jpg 5.jpg (1.06 MB, 6 views)
File Type: jpg 6.jpg (1.03 MB, 7 views)
sonicunderground is offline   Reply With Quote
Old 08-11-2020, 07:31 PM   #2
Badcaps Veteran
Join Date: Jul 2004
City & State: North Springfield, Vermont
My Country: USA
Line Voltage: 118-127V 59-63.5 Hz-> actualizo: pérdido de voltaje
I'm a: Knowledge Seeker
Posts: 5,246
Default Re: Need Help Thermaltake Litepower 500W Problem

First photo: Too much flash glare!
MSI B450 Tomahawk

Ryzen 7 "Matisse" 3700X

16 GB Corsair Vengeance LPX DDR4 SDRAM

XFX Radeon RX 580 8 GB

eVGA Supernova G3 750W

Received on November 4, 2019:
MSI GF63 Thin 9SC-649US

"There's nothing more unattractive than a chick smoking a cigarette" -Topcat

"Don't eat yellow snow!" -Salem

"did I see a chair fly? I think I did! Time for popcorn!" -ratdude747
RJARRRPCGP is offline   Reply With Quote

Thread Tools

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 Technical Forums © 2003 - 2020
Powered by vBulletin ®
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 11:01 AM.
Did you find this forum helpful?