Hi,
I have a PSU Hypex SMPS400A400 that is dead. I want to repair it but some of the components are exploded.
Could you please indicate the reference of the following components:
T14 (located near to the diodes bridge rectifier)
D43, T7 and R23 which are SMD components located just below the main capacitors.
Thank you in advance
I have a PSU Hypex SMPS400A400 that is dead. I want to repair it but some of the components are exploded.
Could you please indicate the reference of the following components:
T14 (located near to the diodes bridge rectifier)
D43, T7 and R23 which are SMD components located just below the main capacitors.
Thank you in advance
Welcome to the forum! 
But we don't know you yet 😉 . . or your test equipment . . or your experience or ability. A high-power high-performance high-density switching supply -- offline, no less -- can be a challenge even for someone with extensive experience. Exploded components add extra drama -- and risk.
I'm also a little confused by your request --
) IS the reference. Is it the component VALUES you are after?
If the main transformer is one of those that exploded, an exact replacement from the manufacturer is the only reasonable choice. The challenge then would be to find and replace the other failed parts before destroying the new transformer.
We also need to know -- do you have/need a schematic? (please post it if you have it) -- how did it fail?
Cheers

But we don't know you yet 😉 . . or your test equipment . . or your experience or ability. A high-power high-performance high-density switching supply -- offline, no less -- can be a challenge even for someone with extensive experience. Exploded components add extra drama -- and risk.
I'm also a little confused by your request --
-- then you list component designations, which to my way of thinking (maybe it's just meLolo82 said:Could you please indicate the reference of the following components:

If the main transformer is one of those that exploded, an exact replacement from the manufacturer is the only reasonable choice. The challenge then would be to find and replace the other failed parts before destroying the new transformer.
We also need to know -- do you have/need a schematic? (please post it if you have it) -- how did it fail?
Cheers
Hi Rick,
Thank you for your reply.
I am indeed new on the forum.
I will do a quick summary of my experience with electronic repair.
I am used to do electronic repair of all types including hifi or other types. I am used to debug electrical circuits. I have a multimeter, LCR meter, oscilloscope, laboratory power supply and signal generator.
I am also equipped for soldering standard and SMD components.
But it is my first trial repairing a class D amplifier.
I indeed need the value of the components listed above. Sorry for the confusion and for my poor english. I am not an american/english native speaker.
I fully agree with you, if the main transformer is damaged, repairing the PSU will be very difficult.
The part that has been destroyed is linked to the power supply to the PWM controller (TL494 in this PSU) and not to the transformer, that's why I hope this PSU is still fixable.
I did not find the schematic. From what I can understand on the board, the power is taken on the primary part downstream of the bridge rectifier and main capacitor through the transistor T14. The other parts that are damaged are linked to the voltage regulation but for the time being, I do not know how.
It seems that failure of T14 is quite common on this PSU and that other components are burned when it happens (which I can understand as 340V sent to low voltage SMD components leads obviously to some damage). What a pity not including fuses on this part of the board.
I bought a defective amplifier (Audiocontrol Rialto 400) and the Hypex400A400 is the main PSU for it. It was already damaged so I do not know how it failed. The stand by power supply is working so I can exclude lightning strike related issue.
Cheers,
Thank you for your reply.
I am indeed new on the forum.
I will do a quick summary of my experience with electronic repair.
I am used to do electronic repair of all types including hifi or other types. I am used to debug electrical circuits. I have a multimeter, LCR meter, oscilloscope, laboratory power supply and signal generator.
I am also equipped for soldering standard and SMD components.
But it is my first trial repairing a class D amplifier.
I indeed need the value of the components listed above. Sorry for the confusion and for my poor english. I am not an american/english native speaker.
I fully agree with you, if the main transformer is damaged, repairing the PSU will be very difficult.
The part that has been destroyed is linked to the power supply to the PWM controller (TL494 in this PSU) and not to the transformer, that's why I hope this PSU is still fixable.
I did not find the schematic. From what I can understand on the board, the power is taken on the primary part downstream of the bridge rectifier and main capacitor through the transistor T14. The other parts that are damaged are linked to the voltage regulation but for the time being, I do not know how.
It seems that failure of T14 is quite common on this PSU and that other components are burned when it happens (which I can understand as 340V sent to low voltage SMD components leads obviously to some damage). What a pity not including fuses on this part of the board.
I bought a defective amplifier (Audiocontrol Rialto 400) and the Hypex400A400 is the main PSU for it. It was already damaged so I do not know how it failed. The stand by power supply is working so I can exclude lightning strike related issue.
Cheers,
A new replacement board seems to be around $100, so it may be easier and no more costly
to just replace it, and not have the difficulty and aggravation. Maybe you could sell the bad board
on ebay as for parts only.
to just replace it, and not have the difficulty and aggravation. Maybe you could sell the bad board
on ebay as for parts only.
Is it possible to attach pictures of the power supply from both sides? Are you a maintenance technician or are you just a hobbyist?
Sounds like your bench is pretty well equipped. I might suggest a dim-bulb tester; and a dummy load to test the supply -- at least the minimum load.
Then all we need is a schematic (*) . . Anybody? I'm striking out so far.
+1 rayma, though, as usual 😀
Regards
* without violating any Copyrights or Intellectual Property conventions
Then all we need is a schematic (*) . . Anybody? I'm striking out so far.
+1 rayma, though, as usual 😀
Regards
* without violating any Copyrights or Intellectual Property conventions
Oh, and forgot -- you may need an isolation transformer to service this safely.
And regarding your English, it's excellent! Any forum I've been on has plenty of folks, with worse English, and NO second language!
I'm sure only sorting terminology occasionally will slow us a bit.
Cheers
And regarding your English, it's excellent! Any forum I've been on has plenty of folks, with worse English, and NO second language!
I'm sure only sorting terminology occasionally will slow us a bit.
Cheers
Hi all,
Thank you for your reply and interest.
To answer your questions and remarks, I am just a hobbyist. I could buy a new PSU for sure but repairing it is more a challenge and learning activity than something really cost effective.
As the transistor T14 is shorted to ground, the main fuse blows as soon as the PSU is powered. So I can't test it with dummy load for the while.
I found some values for a "similar" PSU Hypex400A180. I will try replacing the blown components and see what will happen. There is not much more I can do without the schematic.
An isolation transformer is indeed an excellent idea from a safety point of view. I will try to find one.
Thank you for your advice!
Thank you for your reply and interest.
To answer your questions and remarks, I am just a hobbyist. I could buy a new PSU for sure but repairing it is more a challenge and learning activity than something really cost effective.
As the transistor T14 is shorted to ground, the main fuse blows as soon as the PSU is powered. So I can't test it with dummy load for the while.
I found some values for a "similar" PSU Hypex400A180. I will try replacing the blown components and see what will happen. There is not much more I can do without the schematic.
An isolation transformer is indeed an excellent idea from a safety point of view. I will try to find one.
Thank you for your advice!
Lolo, I have a 400A180. Let me know if you need more component values. I will put it in a new box in the next couple of days and can post a picture of the PCB underside when dissembeled
Hi Joe,
The values I found on internet for the components are:
T14: MPSA44 or KSP44
T7: 1B
R23: 390 ohm (expected to be marked 391 on the resistor)
D43: 5.6V zener diode. (expected to be marked either 5v6 or W9 but other marking are also possible)
Could you please confirm those values?
Thanks a lot for your help
The values I found on internet for the components are:
T14: MPSA44 or KSP44
T7: 1B
R23: 390 ohm (expected to be marked 391 on the resistor)
D43: 5.6V zener diode. (expected to be marked either 5v6 or W9 but other marking are also possible)
Could you please confirm those values?
Thanks a lot for your help
Puh, that SMD stuff is tiny.
My board is a relatively new SMPS400A180, I guess it is the latest revision.
Anyway, on my board the parts are marked as follows.
T14: t09
T7: 1Bt
R23: 221
D43: DB (?, could also be D8)
I am posting a picture for reference of the locations but you can only read the marks on the resistors.
My board is a relatively new SMPS400A180, I guess it is the latest revision.
Anyway, on my board the parts are marked as follows.
T14: t09
T7: 1Bt
R23: 221
D43: DB (?, could also be D8)
I am posting a picture for reference of the locations but you can only read the marks on the resistors.
Attachments
Thank you Joe! It is indeed very small and difficult to be read without a microscope.
For D43, D8 corresponds to a 7v5 zener diode while DB to a 12v zener diode. I would guess that DB is the correct one as someone already mentioned it as 12v.
It seems indeed that your PSU is a new model and that the design has been reviewed which can explain why some discrepancies can be found in the values indicated on internet.
My model must be much older (V14 board). T14 is not a smd on mine.
You have been really helpful. Thank you for your support.
For D43, D8 corresponds to a 7v5 zener diode while DB to a 12v zener diode. I would guess that DB is the correct one as someone already mentioned it as 12v.
It seems indeed that your PSU is a new model and that the design has been reviewed which can explain why some discrepancies can be found in the values indicated on internet.
My model must be much older (V14 board). T14 is not a smd on mine.
You have been really helpful. Thank you for your support.
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