Wii U gamepad power supply  - Page 1
Forum section: electronics / repair

author: blauerscharik
author_rank: Regular Contributor
timestamp: February 09, 2025, 05:47:58 pm
content: Hi there,The power supply of the Wii U gamepad stopped working today.After opening it I found that the rectified cap has 320VDC so the input seems fine, but I don't get anything out on the output.I don't see anything burnt and haven't found anything shorted so far.Any ideas?

author: benj38
author_rank: Frequent Contributor
timestamp: February 09, 2025, 08:16:34 pm
content: Perhaps the easiest is to try and get the datasheet for the controller IC1, and see if its pins have the expected voltages and waveforms.

author: blauerscharik
author_rank: Regular Contributor
timestamp: February 10, 2025, 07:00:13 pm
content: Quote from: benj38 on February 09, 2025, 08:16:34 pmI tried that. Couldn't find anything. The IC says:1691-11ROSGWAB 1234

author: benj38
author_rank: Frequent Contributor
timestamp: February 10, 2025, 07:45:09 pm
content: Quote from: blauerscharik on February 10, 2025, 07:00:13 pmToo badNext step in the "let's hope I'm lucky" approach to repair: check all the electrolytic capacitors' ESR and capacitance.Also, check if the controller IC gets any reasonable DC supply (any two pins).

author: Harry_22
author_rank: Frequent Contributor
timestamp: February 10, 2025, 07:54:20 pm
content: PWM controller is iW1691

author: blauerscharik
author_rank: Regular Contributor
timestamp: February 16, 2025, 12:14:08 pm
content: Quote from: Harry_22 on February 10, 2025, 07:54:20 pmIs that what I should check?

author: benj38
author_rank: Frequent Contributor
timestamp: February 17, 2025, 09:03:07 pm
content: Quote from: blauerscharik on February 16, 2025, 12:14:08 pmIt is not really clear what you are asking. @Harry_22 identified the IC for you, so you can follow my initial advice.Here is the datasheet :https://u.dianyuan.com/upload/space/2011/05/17/1305625537-458666.pdf

author: MathWizard
author_rank: Super Contributor
timestamp: February 19, 2025, 04:47:23 am
content: If I was going to probe it plugged in, I'd solder on a few test leads for sure, and check the common places, like the low voltage supply for the IC. Do you have a scope, that makes seeing the gate drive real easy.Personally I'd remove those big caps to check their ESR, or at least capacitance, and then make a map of the circuit. There's not very much to it, so it should be a pretty standard "forward converter" or similar type SMPS.

author: blauerscharik
author_rank: Regular Contributor
timestamp: February 22, 2025, 07:21:33 am
content: Quote from: benj38 on February 17, 2025, 09:03:07 pmUnderstood, will do. Thanks a lot.

author: blauerscharik
author_rank: Regular Contributor
timestamp: February 22, 2025, 07:23:38 am
content: Quote from: MathWizard on February 19, 2025, 04:47:23 amI don't have a scope yet.The ESR of the caps measured fine, but they were still in circuit though.Thanks

author: blauerscharik
author_rank: Regular Contributor
timestamp: February 28, 2025, 02:10:39 pm
content: I checked the input and output of the IC.Pin2 - 0,42VPin3 - 0,74VPin6 - 0,7VPin7 - 0,7VPin8 - 0,7VIs the IC toast?

author: tom66
author_rank: Super Contributor
timestamp: February 28, 2025, 02:25:16 pm
content: What were you using as ground?

author: blauerscharik
author_rank: Regular Contributor
timestamp: February 28, 2025, 02:32:47 pm
content: Quote from: tom66 on February 28, 2025, 02:25:16 pmThe negative side of the caps and GND of the IC, same result

author: tom66
author_rank: Super Contributor
timestamp: February 28, 2025, 10:57:48 pm
content: OK, with power off, check resistance from pin 8 to pin 7 and pin 7 to pin 5 (FET driver), and resistance from pin 8 to pin 5 (Vcc supply). I suspect the controller is indeed dead.

author: blauerscharik
author_rank: Regular Contributor
timestamp: March 01, 2025, 08:06:20 am
content: These are the results:pin8-7 = 220ohmpin7-5 = 3,2kohmpin8-5 = 3,0kohm

author: fzabkar
author_rank: Super Contributor
timestamp: March 01, 2025, 06:19:20 pm
content: The startup resistors connected to pin #3 appear to be open. Take care when troubleshooting in this area. That's because the bulk capacitor will retain rectified mains voltage even when the PCB is powered down.

author: benj38
author_rank: Frequent Contributor
timestamp: March 01, 2025, 06:45:32 pm
content: @blauerscharik, do you understand the basics of what is going on in the "typical application circuit" in the datasheet?As @fzabkar said, please be very careful.With the power off, please measure between pin 3 and 8, with your DMM in diode mode. You should see a diode voltage drop when the positive DMM terminal is connected to pin 3 and the negative to pin 8.The way this controller starts up is that it has to get at least 12V at pin 3, and it uses that voltage to charge up the capacitor connected to pin 8 through a diode that is inside the IC. Your voltage measurements indicate that this is not happening, which is why @fzabkar suspects the resistors feeding pin 3 are bad.

author: tom66
author_rank: Super Contributor
timestamp: March 01, 2025, 07:39:44 pm
content: Pin 8 to 7 being 220 ohm would point to a damaged driver IC. It's worth checking the main FET is not damaged, this would normally blow the fuse, but in some cases I've seen the current sense resistor go bad first. You might expect the voltage at pin 3 to be low if the IC is faulty. If the FET tests ok, I would consider replacing the controller IC.

author: MathWizard
author_rank: Super Contributor
timestamp: March 02, 2025, 03:57:11 am
content: One of those $20 scopes would come on handy for something like this.With it unpowered, and discharged, a DMM should find most of any external problems, especially if you removed or lifted the legs of some caps.With it powered up, yeah you should have some huge resistors from high voltage, down to the low voltage 12V or so for the startup power of the IC on pin 3. And once it gets running, there's a winding that will take over and provide greater power to the pin8 Vcc of the IC.Like others said, such low voltage on pin 3 isn't right at all. But you said the rectifier works, so yeah I'd check those high value resistors, sometimes they'll have a diode or zener too, and the cap there can fail too.

author: blauerscharik
author_rank: Regular Contributor
timestamp: March 02, 2025, 09:07:37 am
content: There are two resistors after the rectifier to pin3 R36(595=5,9mohm) and R37(225=2,2mohm)I took them both out and they measure fine.After the rectifier I got 320V, after the first resistor I drop to 79V and after the second to 0,75V...Diode measurement from pin8 to pin3 is good, 0,5VThe FET is fine too. No fuses where blown.

author: tom66
author_rank: Super Contributor
timestamp: March 02, 2025, 11:08:54 am
content: All your readings suggest a bad controller IC, not much can go wrong on these if the FET is okay. So I would replace that and go from there.

author: blauerscharik
author_rank: Regular Contributor
timestamp: March 02, 2025, 11:24:50 am
content: Why is 0,7V on pin3 too low?What should it actually be?And if the IC is defective, shouldn't I have still the right Voltage at pin3?Where can I find this IC?

author: benj38
author_rank: Frequent Contributor
timestamp: March 02, 2025, 01:01:03 pm
content: Quote from: blauerscharik on March 02, 2025, 11:24:50 amIt should be around 12V.Before condemning the controller, please check that the capacitors from pin 8 to ground and from pin 3 to ground are not shorted, and that the diode connected between pin 8 and the transformer is not shorted either. Also check the the two resistors connected to pin 2.

author: blauerscharik
author_rank: Regular Contributor
timestamp: March 02, 2025, 05:18:36 pm
content: The capacitors on pin 8 and pin 3 are not shorted to ground.The cathode of the diode is connected to pin 8 and the anode to ground and the coil of the transformer, no short.The two resistors on pin 2 have the correct value (90kohm and 3,3kohm).

author: benj38
author_rank: Frequent Contributor
timestamp: March 02, 2025, 06:13:57 pm
content: Quote from: blauerscharik on March 02, 2025, 05:18:36 pmI believe you will find that the anode is connected to one end of a transformer coil, whose other end goes to ground (since the coil has a very low DC resistance, it will look like the anode goes to ground if simply measured in circuit).I am sorry to say, it is almost certain that the controller IC is dead.

author: blauerscharik
author_rank: Regular Contributor
timestamp: March 02, 2025, 06:23:19 pm
content: Too bad, but thanks a lot.Can I get that IC anywhere?Or is it going to be an unreasonable repair?

author: tom66
author_rank: Super Contributor
timestamp: March 02, 2025, 09:09:08 pm
content: If you can get it on Alibaba or eBay then it's a possible repair, personally I wouldn't put too much time into a power supply you can buy for probably ~$20 second hand or even new in some cases.

author: blauerscharik
author_rank: Regular Contributor
timestamp: March 03, 2025, 07:57:36 am
content: Yeah you're right. I looked on ebay and a genuine used Nintendo goes for like 20 Euros. And a knockoff for about 10 Euros.And 5 pieces of that IC cost also 20 Euros, so unfortunately economically not very reasonable.

author: MathWizard
author_rank: Super Contributor
timestamp: March 03, 2025, 03:36:00 pm
content: Aside from pin out differences, and maybe having to change a few values R or C values, just about any "off-line" step-down buck converter chip should do. Shipping costs aside, it should be dirt cheap to find a very similar IC.Very similar IC's can be salvaged from a lot of things too, like phone chargers, computer PSU's, DVD players, TV's, probably coffee machines too.

author: blauerscharik
author_rank: Regular Contributor
timestamp: March 05, 2025, 06:01:30 pm
content: I will keep an eye out in my future disassemblies, but I'm not gonna order an extra one.