Testing SMPS
If you repair SMPS and wish to test it, make sure the load that you are using is big eough for the SMPS. A small load would not turn “On” the SMPS in fact it would cause the SMPS to shut down or even run at a lower voltage (instead of producing 12 volt, the SMPS now only output 7 to 9 volts). If you don’t get the right amount of load to test the SMPS, you might have thought that the SMPS have problem again.
What kind of load do i need to use? Well it depends on what type of SMPS you are repairing. If you are fixing the computer power supply i suggest that you use a motherboard with at least on or two hard disk. You can buy those used motherboards and hard disk from any computer shops. Some power supply only requires a lamp (light bulb) or resistor to work but i do came across some that only will power up with the original load. Hope after reading this post you will make your own decision on what type of loads that you need to use on the Switch Mode Power Supplies.
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rommel
December 14, 2008 at 1:42 am
pls!send me information about smps, and What kind of load do i need to use thank,s regard
admin
December 16, 2008 at 8:26 pm
The load required is already explained in the post and as for the smps information try visit :
http://www.repairfaq.org/sam/smpsfaq.htm
Jestine
gajender kumar
April 15, 2009 at 7:23 pm
my smps give the low voltages
admin
April 15, 2009 at 11:03 pm
HI Gajender,
It could be bad caps (high ESR) in the secondary side of power supply.
Jestine
Ashis Das
February 2, 2010 at 8:31 pm
Dear Sir
I have a bestec ATX SMPS. Which is came for repair in dead condition. I Shorted 14 & 15 No. pin of 20 pin connector. And given 220V AC supply in AC input. But the Set remain Dead, & I Check The primary Section where a Mosfet generate frequency. But I do not know the Checking procedure.So, Sir If you kindly given the know how, then i shall oblige to you.
Thanking you,
yours faithfully
Ashis Das.
Ashis Das
February 2, 2010 at 9:50 pm
Dear sir,
I have a Bestec ATX SMPS for repair, it is nowDead condition. In Primary side there is a MOSFET. AC input & Fuse & Bridge Rectifier Filter capacitor works because there is voltage 300v d.c. But in secondary thereis no 12v no 5v & fan anotrotating.Please give me suggesstion How can I rectiify it.
Thanking you
yours faithfully
AshisDas.
admin
February 3, 2010 at 4:31 pm
Hi Ashis,
Have you test all the componenst in the primary side? What about the output diode in secondary side?
Jestine
admin
February 3, 2010 at 8:21 pm
HI Ashis,
You need to learn how to test electronic components in order to check the primary side components. It may be one of the component have problem that cause no power symptom.
Jestine
admin
February 5, 2010 at 4:06 am
HI Agam,
More testing method can be found from my ebook at http://www.PowerSupplyRepairGuide.com
Jestine
AGAM
February 5, 2010 at 5:35 am
send me informations abt SMPS TESTING
sandil
May 13, 2010 at 2:08 am
how to chek smps tansformer
admin
May 13, 2010 at 3:06 am
HI Sansil,
You need a Blue ring tester to test the primary winding. Please visit http://www.electronicrepairguide.com/blue-ring-tester.html
Jestine
vipul
September 9, 2010 at 1:06 am
respected sir/madam,
i am student of government engg. college,gujarat. i have try to make smps of three difference voltage. i have no information about testing. so please sir give me all information about testing of smps to my email id given above.
admin
September 9, 2010 at 7:44 am
Hi Vipul,
All my SMPS testing already been compiled into an ebook at http://www.PowerSupplyRepairGuide.com
Jestine
Ditendra M
December 10, 2010 at 3:22 am
Pls tell me how to fault findig
admin
December 11, 2010 at 11:55 am
HI Ditendra,
Fault finding can be found in the Testing Electronics components and LCD Monitor repair ebook.
Jestine
manjul
January 17, 2011 at 1:19 am
sir
i have a pc but from some days its not booting ...means not giving beep sound on starting from ups and no function operates after that including shut down from cpu and cd rom ejection function. all component have power supply.
admin
January 17, 2011 at 5:35 am
Hi Manjul,
You mean sometimes the power supply cannot be started? If yes then check the filter capacitors in the primary and secondary side. Testing filter cap with ESR meter is much recommended.
Jestine
s.nishanth
January 20, 2011 at 3:22 pm
dear sir
how to failure analysis in smbs
admin
January 21, 2011 at 2:39 am
Hi Nishanth,
I suggest that you visit this link:
http://www.repairfaq.org/sam/smpsfaq.htm
Jestine
Raju khajjidoni
July 3, 2012 at 10:51 pm
Dear sir
voltage variation in adapter in secondary side about 15 to 19 volt then i change the electrolytic capicitor
same problem appear then i checked the primary side in oscillator section for voltage variation
the after i changed the electolytic capacitor but same problem appear please help sir
Jestine Yong
July 4, 2012 at 9:11 am
HI Raju,
Have you replace the power ic and check all the components in the power side including the optoisolator ic and tl431?
Jestine
RAJU
July 7, 2012 at 11:58 am
Thank you .....
Problems is solved when changing the power ic
Jestine Yong
July 7, 2012 at 7:49 pm
Hi Raju,
Good to hear that!
Jestine
mubashir
November 12, 2012 at 12:13 pm
Dear Jestine
A compaq pc I opened today. The power supply of compaq (P4) is different than other power supplies. I checked it. Big capacitor have 280 volts. But no voltages found on secondary side. What I have to do to repair this power supply. Kindly help me in this matter.
Thanks.
Mubashir
Jestine Yong
November 12, 2012 at 8:26 pm
Hi Mubashir,
There are many type of design. I'm not sure if your type have any power ic on it or not. If no power ic I suggest that you check all the components in the primary side and also check for shorted output diode in secondary side. If there is power ic then make sure the power ic is receiving good supply voltage.
Jestine
mubashir
November 12, 2012 at 10:05 pm
Dear Jestine,
I want to send photo of Power supply but no option I found here to add picture with this comment. Is there any other way to send photo.
Mubashir
Jestine Yong
November 13, 2012 at 7:30 pm
Hi Mubashir,
Yes you can send the photos to jestineyong(at)electronicrepairguide.com (at) means @
Jestine