Dell 23.5” ST2320LF Widescreen LED Monitor With No Power Repaired
In fact this is my own LED Monitor. While using the Monitor at home, it just suddenly went dead (power light does not lit). I have a spare LCD Monitor at home and after powering it up I could see the display. This means the LED Monitor indeed have problem.I took it back to my office and started the repair work.
I checked on the fuse first and it was opened circuit. On board testing the bridge rectifier indicated a short circuit. I soldered the bridge rectifier and retested it again and indeed it was shorted. I proceeded to check on the power FET and the big filter capacitor and both components were good.
Tip-Usually if the power FET is good, chances is very high the power IC is in good condition also.
Since I do not have the original part number (GBU4-06) for the bridge rectifier, I had to use a replacement one and found it from a junk LCD Monitor power board. The part number is BL4-06 (600volt 4amp).
The problem now was that the replacement bridge rectifier 4 leads (legs) were much bigger than the original one thus it can’t be fitted into the original holes. I had to use a power drill with the right drill bit to make the holes bigger as seen from the photo below:
I did not power up the set and instead use a 100 watt bulb to connect it across the fuse two points. If there is still short circuit the bulb will light up and won’t go dim. If the power section has no short circuit the bulb will go dim and at the same time you can expect good output voltages from the power supply. Yes, indeed there were output voltages and after putting back the replacement fuse and powered On the set, it came back to life. The below photo was taken from my home.
I told my children that their daddy (me) is a DIY person and managed to repair the LED Monitor and save some $$$$.
This article is brought to you by Jestine Yong
Please give a support by clicking on the social buttons below. Your feedback on the post is welcome. Please leave it in the comments.
P.S- Do you know of any your friends who would benefit from this content that you are reading now? If so, forward this website to your friends or you can invite your friends to subscribe to my newsletter for free in this Link.
(245)Dislikes
(0)
69 Comments
Leave a Reply
Robert
November 25, 2014 at 12:07 pm
Good job, Mr. Yong. It's always good to be able to save money! That's part of the reason I wanted to learn electronics so I could save money repairing my own TV's and devices.
admin
November 25, 2014 at 12:16 pm
HI Robert,
Just imagine I'm not a repairer, I could have send to someone to repair it or to buy a new set. The other day, my USB fan was not working. It rotates very slow like something had stuck inside. Cleaning the fan and with few drops of oil cure the fault.
Jestine
Robert
November 25, 2014 at 12:27 pm
Absolutely. The money we save adds up. I have also saved family and friends some money as well. My friend Michelle took me out for a nice lunch the other day for saving her some money and also gave me some gifts.
admin
November 25, 2014 at 12:52 pm
HI Robert,
That is really good. Keep up the good work.
Jestine
moshe
November 25, 2014 at 12:10 pm
another good job....
admin
November 25, 2014 at 12:13 pm
HI Moshe,
Thanks.
Jestine
biruk aweke
November 25, 2014 at 12:43 pm
HI Jestine very nice solution you are great man thank you for sharing your good and use ful experience.
admin
November 25, 2014 at 12:51 pm
HI Biruk,
You are welcome!
Jestine
mohammedfabis
November 25, 2014 at 12:57 pm
Good job sir
admin
November 25, 2014 at 1:16 pm
HI Mohammed,
Thanks.
Jestine
Austin
November 25, 2014 at 1:19 pm
Congratulation, I troubleshoot similar fault with that your own in CRT TV yesterday,the complaint was dead,then i open the set and move straight to fuse and it was open then i checked power transistor and filter cap, and no any short,then i connected 100 watts bulb to the fuse contacter and the bulb light very bright not going dim or flash,then i go to retifier diode and found one shorted then i replaced all the four diodes and connected the bulb again still lighting bright then i check positor and it was shorted too and i replace it,connected the bulb again still lighting bright then i checked deguss and it was shorted and replace it connect the bulb this time it did not light,then i put new fuse and power the Tv and it came back to life the customer started smiling.
admin
November 25, 2014 at 1:57 pm
Hi Austin
Congratulation.
Jestine
memento
January 7, 2015 at 6:24 am
Hi, can anyone tell me where the positor is located on the board ? (on any picture of this article) ?
Just like Jestine, the main fuse was dead, same for the bridge rectifier.
I'm looking for other dead components, right now.
@Jestine : By the way, I have the choice between two bridge rectifiers 3.15A with 600V nd 3.15A with 800V. Wich one is the best ?
Osman AL Sinnary
November 25, 2014 at 1:58 pm
Thank You MR Jestine
Good Job
admin
November 25, 2014 at 3:49 pm
HI Osman,
You are welcome!
Jestine
Mark
November 25, 2014 at 3:32 pm
Hey Jestine,
When you get home from work the last thing you sometimes want to do is repair work. But the satisfaction you get from repairing the item far out ways the inconvenience.
Thanks for sharing.
admin
November 25, 2014 at 3:57 pm
Hi Mark,
Electronics repair is my first love and by just touching and playing with the test meters/components I'm already excited. It is about the passion. Many times doing the repair work have taken longer hours but the job done gives me the greatest satisfaction.
Jestine
Robert
November 25, 2014 at 4:25 pm
Very well said, Mr. Yong. I concur completely!
asim
November 25, 2014 at 3:59 pm
Good job for the learners
admin
November 25, 2014 at 4:44 pm
HI Asim,
Thanks.
Jestine
beh
November 25, 2014 at 4:08 pm
Hi Mr Yong
thanks for this article.
beh
admin
November 25, 2014 at 4:44 pm
HI Beh,
You are welcome!
Jestine
Tito
November 25, 2014 at 4:42 pm
Jestine,i salute you. You are a real teacher and thanks for the job well done.
admin
November 25, 2014 at 4:56 pm
Hi Tito,
You are welcome!
Jestine
Waleed Rishmawi
November 25, 2014 at 4:45 pm
it is not just the money we save on our own repair but the joy when a dead set comes back to life again. I was working in the shop and my son was watching what I was doing and when the LCD screen came on, he was screaming with joy that it was fixed..loving it
admin
November 25, 2014 at 4:57 pm
Hi Waleed,
You are right is the joy of seeing a dead set coming back to life. Your son can be a future professional repairer.
Jestine
Yogesh Panchal
November 25, 2014 at 5:39 pm
In Bridge rectifier compare photo; Replacement Bridge rectifier's DC output Pins are exact opposite than Original one.while Replacing substitute /installation one can be careful for the same other vice work will become more complicated.
Sir, Congratulations for this attempt.
admin
November 25, 2014 at 5:50 pm
HI Yogesh,
You have sharp eyes. Yes you are right. One has to put it according to the markings. In the above case I had to reverse the replacement bridge rectifier.
Jestine
Mrotieno
November 25, 2014 at 8:27 pm
Kudos Jestine, that good work. You always remain my mentor in the electronics.
admin
November 25, 2014 at 11:49 pm
Hi Mrotieno,
Thanks.
Jestine
Andre Gopee
November 25, 2014 at 9:20 pm
Excellent Job repair Mr. Yong. As always Your repair work is always a pleasure to read and I learn a lot from them.. Thanks for these article and keep up the good work.
admin
November 25, 2014 at 11:48 pm
Hi Andre,
Thanks.
Jestine
Anwar Shiekh
November 26, 2014 at 12:14 am
I have the exact same monitor, and wonder if a surge might be blamed for this failure. I have a lot of tripp-lite isobar surge protectors around the house in case. These have a metal casing, as it does not make sense to me to have a surge protector with plastic housing.
admin
November 26, 2014 at 12:53 pm
Hi Anwar,
Probably could be due to the bridge rectifier itself breakdown that also took away the main fuse.
Jestine
Patrick Yun
November 26, 2014 at 1:46 am
Hello Jestine,
Thank you for sharing your experience. I just wondering about testing bridge rectifier, you said On board testing the bridge rectifier indicated a short circuit.In your ebook, TESTING ELECTRONIC COMPONENTS', you shown us testing method using the analogue meter to set X 10K out of board.
How to test bridge rectifier on board? Voltage test or Resistence test?
And other question is testing power FET. Did you test it on board testing or off board testing? If did it on board, how to test Power FET on board? In your ebook, you using the analogue meter to set X 10K out of board too. I know you said, off board testing is more accurate. But I want to know on board testing method too.
I'm sorry for too many questions.
Thank you.
admin
November 26, 2014 at 12:59 pm
Hi Patrick,
To check bridge rectifier on board use analog meter set to x 1 ohm. If one of the diode is showing two readings meaning to say it is shorted. For testing FET the best is to check off board. If you want to test on board set analog meter to x 1 Ohm and black probe to center pin and red probe to the other pins one at a time. If you get reading usually it means shorted. But you still have to remove the suspected FET out from board to double confirm it that it is really shorted.
Jestine
Patrick Yun
November 26, 2014 at 3:09 pm
I got it!
Thank you very much for teaching practical technique.
memento
January 7, 2015 at 6:05 am
@Jestine
Hi Jestine,
You have published an ebook ("TESTING ELECTRONIC COMPONENTS") ?
Can you give us the link ?
Regards
admin
January 7, 2015 at 10:42 am
Hi Memento,
Here is the link http://www.TestingElectronicComponents.com
Jestine
Merlin Marquardt
November 26, 2014 at 4:10 am
Impressive.
admin
November 26, 2014 at 12:40 pm
HI Merlin,
You are welcome!
Jestine
Corriete
November 26, 2014 at 6:38 am
great job and i like the saving part.
admin
November 26, 2014 at 12:39 pm
Thanks a to all!
Jestine
mwangi
November 26, 2014 at 6:57 pm
`Nice Work sir & thanks for sharing with us;
I have a Dell Model E172FPt the power input ok but display is all white,l have replaced all the caps, the FET IS OK,asist plse where l can get schematic diagram 4 the monitor Sir.
admin
November 26, 2014 at 8:33 pm
HI Mwangi,
White display is usually due to bad LCD panel or no dc supply to the lcd controller board. Make sure the output voltages from the power supply is good.
Jestine
Joshua Oloo
November 26, 2014 at 7:27 pm
Thanks Mr. Yong for sharing the article.keep it up sir.
admin
November 26, 2014 at 8:30 pm
Hi Joshua,
You are welcome!
Jestine
Anthony
December 1, 2014 at 10:09 am
Hi Jestine,
Remember that I told you about the "Google play" softwares? Well,it so happen that I just bought the NuVision 10.1" Tablet from the "Home Shopping Network" program on tv and got these softwares FREE with this tablet.Other softwares will cost money,you can buy a Google play card to download its.Believe it or not,while I was using it,I never notice that there is a missing pixel on the LCD.I thought it was a dirt spot on it.This only show up when there a bright white background.I try to clean it with a special towel and liquid to clean the screen that use for monitors and LCDs.Clean it off with a finger tip,nothing happen.I did a color bars test,it show up.I don't want to heat up the screen to pop up the stuck pixel with a hair dryer.There a glass cover over the LCD,it a touch screen you know.I am sending it back,after all,I got a 90 days warranty on it.Did you know this company is now own by Tmax Digital,not NuVision.I just find out about it.
Humberto
December 3, 2014 at 9:58 pm
Hi Mr. Jestine Yong, good repair. I was checking the datasheets of both bridge rectifiers, and the selection was good. Congratulations.
admin
December 4, 2014 at 8:03 am
Hi Humberto,
Thanks. Both have the same volt and amp spec.
Jetsine
muga emmanuel
December 17, 2014 at 7:59 pm
God bless you for your service
memento
January 3, 2015 at 12:01 am
Hi.
Thanks for the article.
My question is about the "power FET". Is the power FET the black component screwed to the aluminium heatsink ?
It would be awsome if you could designate every component you're talking about.
Thanks and again : good work !
Memento
memento
January 3, 2015 at 12:05 am
By the way, I have the same board except for the LED driver board and my DELL Screen wouldn't start (no LED up, nothing).
(This is my board : http://parts-lcd.com/dell-parts-c-1/genuine-dell-st2320lf-lcd-power-board-491a01051400r-p-247.html)
Your tutorial will help me repear it.
Thanks !
memento
January 3, 2015 at 12:47 am
Could you tell us where the power IC is located too ?
Thanks very much !
admin
January 3, 2015 at 2:46 pm
Hi Memento,
Yes the power FET is the one that is attach to the heatsink and the power IC is at the SIP module.
Jestine
memento
January 6, 2015 at 1:56 am
Thank you !
Robert
January 4, 2015 at 7:01 am
The power IC is #LD7575PS on the SIP power module in the second photo. You can get the datasheet here, http://www.datasheetarchive.com/
memento
January 6, 2015 at 1:59 am
Thank both of you very much for your tips and remarks.
I didn't know http://www.datasheetarchive.com/
It's a gold mine.
Best regards !
Keep saving our days.
Merci !
Robert
January 7, 2015 at 2:22 pm
Hi Memento,
You are welcome.Yes, it is a goldmine. It is my favorite datasheet website.
memento
January 17, 2015 at 2:42 am
I turned out that the fuse and the bridge rectifier were the only two components I needed to replace. My Dell screen is up and running again !
Thanks for your help !
Memento
gaurav
August 3, 2015 at 5:27 pm
Dear jestine sir, thank you for the useful article. I need your help . i have similar monitor which is dead. I opened it up and found R853 (near the main filter capcitor ) burnt . I cant figure out what is its value. Can you please help ( in your figure above it seems like 0.2 ohm is written but can you please confirm the value and type).
Regards
Gaurav
Jestine Yong
August 3, 2015 at 9:29 pm
HI Gaurav,
Yes it is 0.2 Ohm resistor.
Jestine
Gaurav
August 4, 2015 at 8:27 pm
Thanks a lot jestine sir.
Udgzwalle
October 13, 2015 at 8:09 am
Dear sir
i'm a huge fan of urs
i read all ur articles
May god u bless u sir
plz pray for me
one day , i wanna be like u..
U r the best for me
i always remember u in my prayers..
PLZ
KEEP UP THE GREAT WORK, STAY BLESSED..
Thanx
Jestine Yong
October 13, 2015 at 10:07 am
Hi Udgzwalle,
Thanks.
Jestine