Saving Computer SMPS Part-3
1) Intex Smart IT-2045S+ : This was one of the many SMPS that failed in our hospital. Cleaning was done by my colleague saving my time. When I checked up, I noticed that it was not getting on. Ring testing showed short. On checking I found that both the 13007 transistors in the primary switching section were short. The 105/400V cap was burnt. As this SMPS had undergone change of caps during the last service, I only had to replace these two transistors and the Fixed Cap. The fan was found broken (As I had kept the broken portion on the outer ring, the picture would not show the breakage). So, replaced that also. There were no dry solder problems on the board. Hence checked it using my Power Supply tester and giving a load of 12V, 25W Bulb. It worked perfectly well.
2) Mercury KEZ-M225 : This was getting on and did not take load. So checked the caps one by one and found these to be out.
Just see what the reading of two tank capacitors (330uF/200V) showed:
Replaced all the electrolytic capacitors, did a thorough retouch of soldering points and cleaned up the board thoroughly. I liked the way the wires were connected in this SMPS.
These were neatly laid out and it had a plastic holder at the board side which would prevent corrosion and tearing of wires while carrying out repairs. Good design!
The SMPS was found working very well,
when connected to a PS Tester with a load of 12V/25W Bulb.
Missions accomplished and double satisfaction got collected.
This article was prepared for you by Parasuraman Subramanian from India. He is 72 years old and has more than 30 years’ experience in handling antique equipment like Valve Radio, Amps, Reel Tape Recorders and currently studying latest tech-classes conducted by Kerala State Electronics Technicians’ Association. He has done graduation in BBA degree, private diploma in Radio Engineering and retired as MD of a USA company. Presently working as Consultant to Hospital and other institutions.
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Albert van Bemmelen
October 22, 2022 at 2:25 pm
You still make fixing smps units and lcd tv repair sound so easy! If they somehow would limit those high inrush currents on the tank capacitors of smps units, that likely would help in getting a longer life cycle on those caps.
According to this webpage the temperature also plays a major role:
https://www.meanwell-web.com/nl-nl/technote-which-better-e-cap-solid-capacitors
Parasuraman S
October 22, 2022 at 11:14 pm
That is an expert sound advice! Shall take care! Many thanks for the link and comments!
Anwar Shiekh
October 22, 2022 at 11:09 pm
great articles
Parasuraman S
October 23, 2022 at 9:05 pm
Many thanks for your comments and encouragement!
Yogesh Panchal
October 25, 2022 at 2:23 am
Good Repair! Sir,
Parasuraman S
October 26, 2022 at 6:17 pm
Many thanks!