Explosive Failure Of A Maxx AC Adapter Model 1250
This adaptor belonged to the hospital where I worked and was brought to me with the complaint that a loud sound was heard and it became dead. On opening, I was taken aback to see the charred components:
The fuse was blown and the Mosfet had burst and I gathered the number as TOP227Y from my techie friends. The tank capacitor had burst on the top and all the electrolyte got spilled all over inside. It took repeated efforts using IPA and brushes to clean the area thoroughly, as the chemical was conductive.
After ensuring that the board was clean enough and checking the components in the primary and secondary, I replaced the tank capacitor and connected a module to check whether the output was ok.
Since the result was good and it proved that the primary and secondary was ok in the circuit, I replaced rest of the capacitors, retouched the board very well and cleaned it thoroughly.
I also replaced TL431 and opto as a precaution.
Then soldered the Mosfet and its heat zinc as how it was before and checked the DC output and wave form. It was working swell and here is the picture:
Closed the ACA and kept it ready for me to carry it back to the hospital. Mission successfully accomplished adding great satisfaction to its collection.
Very proud to mention that this is my 400th article, which could not have been possible without the support and benevolence of Mr.Jestine Yong and the continued support given by the readers! Many, many thanks to all of you and also to God for making it possible!
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You may check on his previous article on Restored An F&D USB Video Player AC Adapter Model F100
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Anwar Yunas Shiekh
August 12, 2023 at 7:54 am
What would the hospital do without you?
Parasuraman S
August 12, 2023 at 4:24 pm
Many thanks for your encouragement!
UDAY NAPHADE
August 12, 2023 at 9:46 am
Thanks for this informative article.
Parasuraman S
August 12, 2023 at 4:24 pm
Many thanks for your comments!
Albert van Bemmelen
August 12, 2023 at 1:34 pm
Another good article and another milestone reached, congratulations Parasuraman! That undoubtedly have been many replaced ecaps and IPA cleaning jobs!
Parasuraman S
August 12, 2023 at 4:26 pm
Many thanks for your comments, continued support and encouragement, without which I could not have reached the milestone! You are a keen observer and good enough to point out mistakes and correct them, which naturally educates people like us! Special thanks to you too for this support!
Sarath Ranasinghe
August 13, 2023 at 11:15 am
Dear Mr Parasuraman S, what module did you connect to check the PSU primary and secondary before replacing the Mosfet?
Parasuraman S
August 13, 2023 at 8:00 pm
Kindly see the following link to know more about this module. I have covered this in many of my previous articles. https://jestineyong.com/cracked-unknown-pwm-replaced-by-universal-module-in-pressure-monitor-smps/
Also : https://www.youtube.com/watch?v=k2DjupS0Qrc (To know more about this module)
Generally for testing purposes, we do not use the green wire.
Many thanks!
Sarath Ranasinghe
August 19, 2023 at 9:20 am
Sorry Mr, Parasuraman for not thanking you in time due to some unexpected workload. Thousand apologies.
Appreciate your prompt reply.
Yogesh Panchal
August 13, 2023 at 11:32 pm
Good Fix! Sir
Parasuraman S
August 14, 2023 at 1:55 pm
Many thanks!
AdamS
August 14, 2023 at 9:56 pm
Another excellent repair and congratulations on your 400th, Parasuraman!
Parasuraman S
August 15, 2023 at 8:55 am
Many thanks for your comments and support!
Nilton Cezar Vieira
August 16, 2023 at 7:05 am
A good example of corrective and preventive maintenace. Thanks, Sir!
Parasuraman S
August 16, 2023 at 10:02 pm
Many thanks for your comments!
Sibu
August 19, 2023 at 12:08 pm
Good service
Sunil
August 19, 2023 at 3:13 pm
Thanks for ur informative articles...