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

 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old 01-24-2018, 02:04 PM   #1
Behemot
Badcaps Veteran
 
Behemot's Avatar
 
Join Date: Dec 2009
City & State: Prague, 504'52.22"N, 1423'30.45"E
My Country: CZ
Line Voltage: 230 V/50 Hz
I'm a: Knowledge Seeker
Posts: 4,476
Default Acer B326HUL power supply dead

Display only blinks and than stays dead. Check open the PSU revealed it is dead.

There are three output rails: winding to feed the TEA1791T synchronnous rectification controller (this thing has no connection with primary side!), the output for the rectification transistor - this rail feeds the signal board, and than backlight rail.

Seems like the unit only pumps few cycles to the secondary so voltage rises a bit and than falls down as the caps discharge. I have about 15.5 V on a small cap on the primary auxiliary rail just after the diode which slowly falls, pumps again to 15.5 V and that repeats.

There is however oscillating voltage between like 18 and 19.6 V on the cap directly in front of the primary common PFC/PWM controller. Do not think this is normal condition. Cannot identify the controller right now, it has layer of lackquer, gonna have to try removing it.

I do see only 320V on the input cap though, there is no spike suggesting the PFC would be turning on, so maybe the problem lays in here?
__________________
Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

Exclusive caps, meters and more!
Hardware Insights - power supply reviews and more!
Behemot is offline   Reply With Quote
 

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 - 2019
Powered by vBulletin ®
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 01:09 PM.
Did you find this forum helpful?