MTS70-0512ACW going into protection

[JenneDezaeger]

Hi,

I've spend the last 3 days trying to figure out what is causing this smps to go into protection.
Because it only powers on for a split second it's almost impossible to measure anything.
That's why I removed the oscillator board (it's a separate board) and powered it externally.
The TEA1610T showed me this at the gate outputs:

So I assumed a faulty driver and was a bit surprised it went into protection instead of blowing up the FET's.
I replaced the IC (even twice) and I still get the same problem.
Does anyone have an idea what is going on here?

Thanks,

Jenne

[sam_sam_sam]

Re: MTS70-0512ACW going into protection

Are you sure that you do not have a short circuit in the secondary side of the switching power supply or even in the primary side of the switching power supply

Have you checked the startup capacitor with a ESR capacitor tester

( do not use a UF capacitor tester this testing would not tell you what you need to know)

to see this if might be the issue

I would even recommend that you compare the results with a new capacitor of the same UF value for comparison of values and if they are more than 10% difference

I would recommend just replacing them

In fact I would check every capacitor that is less than 100uf

Please show a clear and focus pictures of front and back of the board in question

[CapLeaker]

Re: MTS70-0512ACW going into protection

Sounds like the PSU starts up, sees a short on the output, or something wrong with the feedback, then shuts down. Post some high resolution straight shot pictures top and bottom.

[JenneDezaeger]

Re: MTS70-0512ACW going into protection

All the caps have been tested and even replaced without reason and it didn't make a difference. I took some pictures of the board, but keep in mind that the small boards are out of place zo I could reach them to measure while the PSU is running. I took a separate picture of the oscillator board that I'm now running from a bench supply which gives me the result from my initial post.
Maybe one more thing, when I power the TEA1610T without it being on a pcb or without any passives it off course doesn't oscillate because of the missing components but it isn't working as described in the startup phase from the datasheet. Check p.5 fig 5
https://cdn.badcaps-static.com/pdfs/...9af820868e.pdf
Here you can clearly see that the low gate will rise according to the Vdd but the high gate stays low. This is what I get: (blue is low gate, yellow is high gate)

So what am I missing here? Maybe some external input that will pull the high gate output low?






Thank you for your help already

[sam_sam_sam]

Re: MTS70-0512ACW going into protection

Is It the pictures but the one of the bottom of the board looks like some soldering joint looking very bad like they did not get soldered correctly it looks like some pins have what looks like flux between the pins and the solder

I would recommend reflowing the solder or remove the solder completely and reapply the solder

[JenneDezaeger]

Re: MTS70-0512ACW going into protection

No, that's just flux residue you're seeing. I did work on the board allot and didn't clean it between each thing i tried.