Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting Printers, Copiers, Scanners and other Imaging & Printing Devices
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 08-02-2019, 03:21 PM   #1
Jluxster
New Member
 
Join Date: Jun 2019
City & State: Watertown
My Country: United States
I'm a: Knowledge Seeker
Posts: 13
Default Lexmark 654dn power supply dead fans on part # 40x4355

Hey all,
Working on another failed Lexmark LVPS power supply. The printer gradually had more and more trouble making it to the post screen until finally no power on at all. I'm replacing the two large caps, and the one small 100uf 35V cap that shows a small bulge. That is the only visible cap issue, but I hear a faint fast clicking that tells me caps are probably the issue.

Have a look at this board and let's make predictions about what's wrong with it, I'll post my repair results and we can see what the issue was.

Thanks!
Attached Images
File Type: jpg IMG_20190726_212413.jpg (701.5 KB, 9 views)
File Type: jpg IMG_20190726_212435.jpg (574.0 KB, 19 views)
File Type: jpg IMG_20190726_212422.jpg (560.4 KB, 11 views)
File Type: jpg IMG_20190726_212429.jpg (575.7 KB, 9 views)
File Type: jpg IMG_20190726_212449.jpg (563.7 KB, 9 views)
Jluxster is offline   Reply With Quote
Old 08-02-2019, 06:11 PM   #2
budm
Badcaps Veteran
 
budm's Avatar
 
Join Date: Feb 2010
City & State: S.F. Bay area
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Knowledge Seeker
Posts: 36,374
Default Re: Lexmark 654dn power supply dead fans on part # 40x4355

Bad caps may show no sign of bulging but they can have high ESR. It sounds like you have bad startup/running caps (typical small value 47 ~ 56 uF 50V) in the HOT side, they are for filtering the Voltage for the VCC pin of the SMPS IC's.
__________________
Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956

Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999

Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl

Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/

TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809
budm is offline   Reply With Quote
Old 08-02-2019, 08:03 PM   #3
Jluxster
New Member
 
Join Date: Jun 2019
City & State: Watertown
My Country: United States
I'm a: Knowledge Seeker
Posts: 13
Default Re: Lexmark 654dn power supply dead fans on part # 40x4355

Hmmm, OK, this board has a ton of 35V and 50V caps on it. Perhaps one of them is the culprit.
Jluxster is offline   Reply With Quote
Old 08-02-2019, 09:24 PM   #4
budm
Badcaps Veteran
 
budm's Avatar
 
Join Date: Feb 2010
City & State: S.F. Bay area
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Knowledge Seeker
Posts: 36,374
Default Re: Lexmark 654dn power supply dead fans on part # 40x4355

ton of Lytics cap?
https://www.badcaps.net/forum/attach...2&d=1564777195
I see C501, C801, but the third one I cannot see in that picture.
budm is offline   Reply With Quote
Old 08-02-2019, 09:50 PM   #5
R_J
Badcaps Veteran
 
Join Date: Jun 2012
City & State: ☻
My Country: Canada
I'm a: Professional Tech
Posts: 4,873
Default Re: Lexmark 654dn power supply dead fans on part # 40x4355

I see that one bulged cap and would bet C106 is also bad
R_J is offline   Reply With Quote
Old 08-03-2019, 05:26 PM   #6
budm
Badcaps Veteran
 
budm's Avatar
 
Join Date: Feb 2010
City & State: S.F. Bay area
My Country: USA
Line Voltage: 120V 60Hz
I'm a: Knowledge Seeker
Posts: 36,374
Default Re: Lexmark 654dn power supply dead fans on part # 40x4355

Quote:
Originally Posted by R_J View Post
I see that one bulged cap and would bet C106 is also bad
Good eyes!
https://www.badcaps.net/forum/attach...0&d=1564777195
Time to recap as a set.
budm is offline   Reply With Quote
Old 08-03-2019, 08:08 PM   #7
CapLeaker
Leaking Member
 
CapLeaker's Avatar
 
Join Date: Dec 2014
City & State: Atlantic Canada
My Country: Canada
Line Voltage: Ground, 0Hz
I'm a: Hobbyist Tech
Posts: 4,183
Default Re: Lexmark 654dn power supply dead fans on part # 40x4355

replace all caps that are near a heat source. big or small, doesn't matter much.
CapLeaker is offline   Reply With Quote
Old 08-04-2019, 01:29 PM   #8
Jluxster
New Member
 
Join Date: Jun 2019
City & State: Watertown
My Country: United States
I'm a: Knowledge Seeker
Posts: 13
Default Re: Lexmark 654dn power supply dead fans on part # 40x4355

Well, last night I replaced the bulged cap and the two large caps, and the unit now functions with no problems. Startup and post.

Good prediction in naming the small cap as the likely culprit.
Jluxster is offline   Reply With Quote
Old 08-04-2019, 01:31 PM   #9
Jluxster
New Member
 
Join Date: Jun 2019
City & State: Watertown
My Country: United States
I'm a: Knowledge Seeker
Posts: 13
Default Re: Lexmark 654dn power supply dead fans on part # 40x4355

Here are the images after repair.
Thanks for all the posts.
Attached Images
File Type: jpg IMG_20190802_213506.jpg (622.4 KB, 5 views)
File Type: jpg IMG_20190802_213456.jpg (491.1 KB, 5 views)
File Type: jpg IMG_20190802_211041.jpg (600.7 KB, 4 views)
Jluxster is offline   Reply With Quote
Old 08-10-2019, 07:40 PM   #10
CapLeaker
Leaking Member
 
CapLeaker's Avatar
 
Join Date: Dec 2014
City & State: Atlantic Canada
My Country: Canada
Line Voltage: Ground, 0Hz
I'm a: Hobbyist Tech
Posts: 4,183
Default Re: Lexmark 654dn power supply dead fans on part # 40x4355

glad to hear that you got it going again!
CapLeaker 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 - 2019
Powered by vBulletin ®
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 01:39 AM.
Did you find this forum helpful?