ACER 7254E CRT Monitor Repaired
I got this monitor from my friend for free. I like to repair although didn’t get profit and have planned to give this to the others. It is good to sharpen our troubleshooting skill from broken devices. I took this monitor home and start my job. When I connected it to PC and turn it on, the power on led indicator just blinks. There was no picture, I tried to put my back of hand to in front of CRT screen to feel the high voltage, I don’t feel it. It looks something shorted because the power on led indicator just blink and I was sure it has to do with secondary side on SMPS.
I took the cover out and start my troubleshooting. The first thing that I do was to look for any burnt components, bulged capacitor or dry joints but I found the bottom of PCB looks good and clean. I tested secondary diodes and one diode looks suspicious when I tested it with my multimeter on board. I removed one of this diode leg to make sure and those diode just tested good. This diode trace going to vertical circuit but I couldn’t find any faulty component.
Sometimes power blink could causes by defective horizontal circuit. I have tested the flyback with Ring Tester and internal capacitor also tested good. HOT and damper diode were checked good too. Scan through B+ circuit, finally I found B+ FET IRF630M is shorted when I check it on board. I removed it and make sure those B+ FET were developed short circuit.
When semiconductor failed, sometimes another component causes it or it just failed itself. I don’t want to make mistake so tried to check surrounding components and all were checked good. It is time to change it and see what will happen, if this didn’t cure the problem I have to troubleshoot further.
Thanks God, this monitor alive again. I can see clear picture coming out and happy to keep this out of landfills.
This article is contributed by Rudi Wijaya from North Sumatera Medan (Indonesia). He is an electronics repair hobbyist and specializes in TV, Monitor and DVD repair. He usually repairs the items that belong to friends and family.
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Atish Chand
August 18, 2014 at 12:31 pm
Thanks Rudi
Rudi Wijaya
August 19, 2014 at 3:01 am
You are welcome !
Rudi
Rudi Wijaya
August 19, 2014 at 10:56 am
You are welcome.
Rudi Wijaya
Venu gopal
August 18, 2014 at 1:29 pm
well done , Thanks for the nice article.
Fayaz
August 18, 2014 at 2:14 pm
Dear Rudi,
In what section you found that FET faulty?
Rudi Wijaya
August 19, 2014 at 3:10 am
I found that FET failed on B+ circuitry. You can tell from those B+ coil just right beside this FET.
Rudi Wijaya
yogesh panchal
August 18, 2014 at 2:26 pm
Rudi,
Thanks for sharing the article and i am totaly agree with you that practice will sharpen our troubleshooting skill.
hongkongpom
August 18, 2014 at 6:08 pm
Your comment about keeping it out of the landfill at the expense of a single component is so prudent because these monitors contain so many dangerous materials...well done my friend!
peter mlcciche
August 18, 2014 at 9:27 pm
Thank you for very interesting article
These articles are very much appreciated
reza
August 18, 2014 at 10:42 pm
hello
i am reza from iran
i read this artice
and i use your experiance.
Ekundyor
August 18, 2014 at 11:53 pm
Thanks,
The lesson is rewarding!
Humberto
August 19, 2014 at 1:03 am
Good repair Rudi Wijaya, congratulations
Rudi Wijaya
August 19, 2014 at 3:04 am
You are welcome, everyone !!
Rudi Wijaya
Imraz
August 19, 2014 at 4:54 am
Nice diagnostic and repair work keep it up
kiet le
August 19, 2014 at 6:14 am
Good work!
Abdul
August 19, 2014 at 9:43 am
Rudi,
Thank you for contributing the article.
Hope to hear you often.
Corriette
August 19, 2014 at 10:07 am
great job done
Andre Gopee
August 19, 2014 at 10:33 am
Rudi I like your way off thinking...Keep them out of the land fill. Nice work keep it up.
Taring K Arioka
August 19, 2014 at 11:12 am
Thank you for sharing
Joshua oloo
August 19, 2014 at 2:46 pm
Thanks for sharing the repair tips.keep up the spirit.regards
ramex
August 19, 2014 at 4:12 pm
nice tip of the day ,very good fault verification ,professional way of solving electronic faults but it would much appreciated if testing method on the bad fet had been shown.any ways keep up with your good wook. thanks buddy.
Rudi Wijaya
August 19, 2014 at 6:19 pm
ok, I noted it. you are welcome !
Rudi Wijaya
jakeryan
August 21, 2014 at 7:26 am
very nice topic... thanks a lot... more power
Raymundo Saura
August 27, 2014 at 4:31 pm
thanks for sharing sir a great article for me very new in this world of electronics thank you sir
Osman Alsinnary
September 6, 2014 at 10:33 pm
Good Job
I faced this problem before with an LG 710
Osman Alsinnary
September 9, 2014 at 7:46 pm
Also the first symptom or indicator of shortage in secondary section the power led blinking . Why ?
Because there is small timer circuit try after 200 uS or 400 uS to start the power supply & trigger the relay & if there is high voltage drop or shortage in the secondary section it trigger the relay to disconnect & connect again .
Hero
August 13, 2015 at 12:07 am
Hi!
I am from Hong Kong and have three broken Acer CRT at home, I invited some technicians to fix them but no one successed, I decided to learn how to fix them so your article is a kind of encouragement.
Jestine Yong
August 13, 2015 at 7:14 am
Hi Hero,
Thanks.
Jestine
Parasuraman S
August 20, 2017 at 12:04 pm
Could read this only now. Excellent article!