PS5 PSU ADP-400DR no power

[speggio91]

Hi everyone,

I'm working on a PS5 power supply (model ADP-400DR) that's giving me some trouble. The issue is that no 12V output is coming out.

Initially, I found the DAP053T chip responsible for APFC/LCC/PWM was faulty because it was getting very hot (around 100°C) and had no VCC on pin 13.
I replaced it with an equivalent chip (TEA2016AAT). Now, when I connect the main AC voltage, I measure 395-400V on the main filter capacitor, but the 12V output appears only for a few seconds before it starts dropping to zero.
I then disconnected pin 3 of the optoisolator (EL1013), which controls the shutdown. After this, I sometimes get the 12V output, but it still shuts down intermittently. If I disconnect and reconnect the 220V plug, the 12V will stabilize, but not consistently.
When I tested it under load (6A), the voltage drops to 11.2V, whereas it should stay closer to 11.9V in a properly functioning PSU. During this load test, the main filter capacitor remains solid at 395V.

Any ideas on what could be causing this issue? Is it possible that the replacement TEA2016AAT chip isn't functioning correctly, or could something else be the culprit?

Any suggestions would be greatly appreciated!

[CapLeaker]

Check the ESR on the main filter capacitor. Only because it is stable at 395VDC doesn't mean it has enough capacity for good operation. A bad main filter capacitor can cause the PSU to shut down. Obviously the power supply doesn't like something on the secondary and it shuts down the primary. Now you got to figure out why. I don't think the TEA2016 chip is bad. The PFC is working, it just acts like she runs out of juice or can't regulate properly.

[speggio91]

Thanks for the suggestion!

I desoldered and measured the ESR of both main filter capacitors, as well as all the 12V output electrolytic capacitors. Every capacitor tested fine with 0 ohms ESR, and the capacitance values are within the expected range.

Since the capacitors seem to be in good condition, I'm thinking the issue might lie somewhere around the PWM/APFC/LCC controller (TEA2016AAT). I'm considering checking the resistors and diodes in that area, but if you have any specific pointers or suggestions on which components to focus on, I'd really appreciate the guidance.

[speggio91]

I have an update: I found that a 30Ohm resistor that connects the TEA2016AAT to GND was broken, so I replaced it and now the power supply will output the 12V without shutting down.
The problem now is that it fails under load. Even at lower currents the voltage drops drastically, e.g. at 4A it drops to 10.9V. The voltage on the filter capacitors remains stable at around 395V, but sometimes it goes up to 410V, especially when I disconnect the load.

Do you think the problem is on the secondary side? Because I think the PWM and APFC are working fine.

[CapLeaker]

The feedback starts in the secondary and ends at the PWM in the primary side. The problem could be on either side. There are a few reasons like a small cap, the voltage reference or maybe a zener diode etc is bad. Could be the optocoupler isn't turning fully on too. Sometimes it helps if you draw out a schematic.

[redbaron1007]

On these PSU's it's usually good practice if you've had to replace the DAP053T to also replace all the optocouplers. If they aren't the issue then it's most likely something like CapLeaker mentioned. Without having one of my working (recently refurbished by me) ones in front of me or my notebook with what work I did to refurb them I couldn't give you much more details on exactly what it could be. My notes and working PSU's are on a shelf at work.

Side note about the opto's. They are a pain in the ass to remove sometimes because of the glue they use to hold them down. If you're using hot air to remove them it's really easy to delaminate the board and if you're using just a soldering iron I'd desolder the legs and "carefully" grab it with a pair of needle noses and twist just enough not to damage the board.

[speggio91]

Thanks everyone for the suggestions so far!

I've done some more troubleshooting since my last post. I replaced all three optocouplers, and I've also tested all the diodes, zener diodes, transistors, and resistors on the primary side. None of them seem to be faulty. I haven't tested any of the capacitors yet, so that's still an area to explore.

At the moment, I'm focusing more on the secondary side, where there's a DAS01B chip that I suspect might be a control chip communicating with the optocouplers, but unfortunately, there's no datasheet available for it. I've already tested all the resistors, diodes, and transistors around that chip, and nothing has come up faulty so far. There's also another chip on the secondary side, the MP6924A, which controls the synchronous rectification, and I do have the datasheet for that one, I've attached the typical application circuit.

I recently watched a video by Totelmerc https://youtu.be/Fj3aExUD0FI?si=Tucev0lz6Zg2FlV_&t=2705 where he dealt with a similar issue—his power supply failed under load too, though in a more drastic way than mine. He found a shorted capacitor connected to the control chip (in his case, the DNP014, different board from mine). That's got me thinking that the capacitors on the secondary side might be the next thing to check.

A friend of mine also has a working 400DR power supply, and they'll be sharing some measurements from around both the DAS01B and MP6924A chips. I'll use that data to pinpoint the exact area to focus on.

I'll keep you all posted as I go further with this. Thanks again for all the input!