Question What exactly is the U10 chip?

loopj

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Hey all, I'm wondering if anyone has discovered exactly what the U9/U10 chip is. I'm trying to figure out if it is an off-the-shelf, commercially available component, or a custom chip that Nintendo or one of it's partners made?

It looks to be a SSOP5 package (the same footprint as a transistor SOT23-5 package) but since it is labelled U9/U10 rather than Q9/Q10 I'm 99% sure this is not a transistor.

One of my U10's that I damaged during desoldering has the marking B37G.

I'm wondering for a couple of reasons: a) I'm curious about the role this mysterious component performs, and b) I'm wondering if drop-in replacement chips can be found on mouser/digikey for people who damage their U9 and U10 chips.
 

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The U10 is a supervisory IC that generates a delayed 3.3V signal. It sends the signal to the Wii's Hollywood, letting it know that it's good to go to boot up.

It's probably pretty similar (if not identical) to this voltage detector IC: https://fscdn.rohm.com/en/products/databook/datasheet/ic/power/voltage_detector/bd45xxg-e.pdf

Technically, the U10 could be replaced with a different voltage detector IC, a microcontroller, or even a physical switch. But the U9/U10 is the simplest and smallest solution that exists, so there's no real reason to replace it. Plus, you get two of them for free with every Wii! ;)
 

loopj

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Interesting, so it looks like a ROHM BD45332G (3.3v, 200ms delay, open drain) or ROHM BD46332G (3.3v, 200ms delay, CMOS) might be a drop-in replacement. I can't tell at a glance if the open drain or cmos model is the correct one here.

In my case, I damaged U9 and U10 by being too clumsy with my removal. I'm thinking spending a couple of dollars on some replacement chips is cheaper than me buying a new motherboard.
 

jefflongo

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Interesting, so it looks like a ROHM BD45332G (3.3v, 200ms delay, open drain) or ROHM BD46332G (3.3v, 200ms delay, CMOS) might be a drop-in replacement. I can't tell at a glance if the open drain or cmos model is the correct one here.

In my case, I damaged U9 and U10 by being too clumsy with my removal. I'm thinking spending a couple of dollars on some replacement chips is cheaper than me buying a new motherboard.
I would wager probably CMOS because there's no pullups on the output. IIRC the function is to time a reset interrupt on the Hollywood after it has ample time (200ms) to power up. @Aurelio knows for sure I believe.

I would be interested to see if this would work as a drop in replacement. I think it actually could work.
 

Aurelio

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On the Wii motherboard there's actually a 4.7k pullup on the u10 output, but when we trim the wii we get rid of it. This makes me think that even if there's a pullup, the IC they used is CMOS.
 
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Look what arrived

Will try adding it to a fresh mobo.
I'm eager to see if you can get them working. I ordered a couple a few weeks ago and couldn't get them to work on untrimmed or trimmed mobos. A deeper read into the DS indicates that the ER line might need to be pulsed to start the POR timer, but it also says that you can tie ER to GND if it's unused (which is what U10 seemingly does)
Screenshot_20200317_214422_com.google.android.apps.docs~2.jpg
Screenshot_20200317_214408_com.google.android.apps.docs~2.jpg
The sheet also shows application circuits with ER grounded. But I couldn't get the ICs to output 3v3 at all, even just hooked up to my benchtop PSU. Probably just a dumb mistake on my end. Please keep us updated!
 

mokus

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There’s a decent chance that 3.3v threshold part is too high. I’m getting a parts order ready for something else and thinking I might throw in a 3.0V version. Then after a swap, I can test the original in isolation and see if I can figure out more specifics.
 

mokus

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I ordered the parts but then I got impatient and pulled the original anyway. I can confirm my guess was correct - the original has a 3.0V threshold. Additionally, it is open-drain and has about 160ms delay.

edit: improved my timing measurement setup a bit. This particular unit has a very consistent 169.6 ms delay. I’ll know for sure in a few days but I’m very confident at this point that the BD45302 will be a drop-in replacement.

Final update - swapped the new parts in (replaced both U9 and U10 with BD45302G) and it works :D. Booted right up like nothing had changed at all.

removed U9 and U10.png replaced U9 and U10.png
 
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Noob here, I can't find anywhere to post this question but does anyone have any advice on how to remove the U10 chip easier? I somehow managed to damage both of my chips when using my hot air station. I brought the temp up to 400+ but it wouldn't budge when I pulled on it with tweezers, and a bit of the black casing chipped off both of the chips. I swear it's a lot harder to remove than other circuit boards I've tried. Does using some cleaner or flux help?

I still want to remove the chips and check if they work anymore, but if they don't I guess I can try ordering the BD45302
 

Gman

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Noob here, I can't find anywhere to post this question but does anyone have any advice on how to remove the U10 chip easier? I somehow managed to damage both of my chips when using my hot air station. I brought the temp up to 400+ but it wouldn't budge when I pulled on it with tweezers, and a bit of the black casing chipped off both of the chips. I swear it's a lot harder to remove than other circuit boards I've tried. Does using some cleaner or flux help?

I still want to remove the chips and check if they work anymore, but if they don't I guess I can try ordering the BD45302
Check this out! https://manual.bitbuilt.net/step/u10-relocation/6
 
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Thanks gman! I do have a hot air station, and I eventually realized I just set the air speed to be too low -_-

I have one more question- can anyone explain how I can test the u10 chip to make sure it still works? I have a power supply and multimeter. Are there any other tools I would need?

Thanks again, I'm new to hobby electronics so this is a big learning experience
 

loopj

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For future travelers, I think I found the original U9/U10 IC - the Ablic S-80129CNMC-JKO.

The JKO matches the part markings on the U9/U10, the pinout matches, and the timings and voltage thresholds line up with what we expect (2.9V, ~200ms).

This is an obsolete part, but hopefully it helps people find a suitable replacement - the Rohm BD45292 matches the specs (rather than the BD45302).
 
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