Gaming GBA EM8 Component Missing - Solution?

[Krystalize]

So I purchased some broken gameboy's off eBay and the SP that came said it has 'EM8 missing' - sure enough it does.

Therefore when plugging in a power supply it will not charge the battery. The person before has also removed fuse F1 and F2 and replaced with some solder across the two contacts.

So my question is what is the solution from here?

I'm not 100% sure what the EM8 does, I've read various different things such as EM8 being bypassed, EM8 component being a custom in house Nintendo part.

 

[FAST6191]

We did see a proper solution a while back. Turns out it is the same as the DS component EM10 which you can buy loads of
https://gbatemp.net/threads/need-help-replacing-charging-port.502008/page-2

It is a choke (an inductor) designed to lessen noise (this would have been way back in the day but still new enough that switch mode supplies were a thing so noise aplenty there. I don't have reliable info on specs for it in case you wanted to go talk to rapid electronics or something. If you do get one and have means of telling how many henries or measure impedance at a given frequency then we would appreciate it.

Bypassing it would probably get it to charge, though I don't like it much. I similarly don't know what f1 and f2 were rated at either.

 

[Krystalize]

We did see a proper solution a while back. Turns out it is the same as the DS component EM10 which you can buy loads of

It is a choke (an inductor) designed to lessen noise (this would have been way back in the day but still new enough that switch mode supplies were a thing so noise aplenty there. I don't have reliable info on specs for it in case you wanted to go talk to rapid electronics or something. If you do get one and have means of telling how many henries or measure impedance at a given frequency then we would appreciate it.

Bypassing it would probably get it to charge, though I don't like it much. I similarly don't know what f1 and f2 were rated at either.

Ahhh brilliant, I have a couple of spare DS lite boards so will have a poke around and see if I can remove the EM10 from one and use that!

In a discord chat a member used a transistor tester. It detected the component as 2 diodes, which might explain why it filters out noise by limiting the top end and bottom end voltage? This is way beyond my comprehension though.

 

[FAST6191]

Those component identification boxes are a bit hit and miss. That said they do usually manage to catch simple inductors* and give fairly reliable ratings for them so I am not sure what goes there. Don't know if there were some fun in circuit effects that made it appear like that.

*I am fairly confident in it being an inductor -- some of the broken ones have the typical spool of magnet wire wrapped around things which no semiconductor diode setup would ever do.

 

[Krystalize]

Those component identification boxes are a bit hit and miss. That said they do usually manage to catch simple inductors and give fairly reliable ratings for them so I am not sure what goes there. Don't know if there were some fun in circuit effects that made it appear like that.

Fair enough - quick question on the EM8/EM10 component; Does the orientation matter? There doesn't seem to be any markings to indicate a orientation.

 

[FAST6191]

Specifics here. No idea. The long sides will want to be on the long sides but simple inductors themselves are not polarity sensitive.
Close ups of this component don't reveal any spots or leg identification markings.

 

[Krystalize]

Specifics here. No idea. The long sides will want to be on the long sides but simple inductors themselves are not polarity sensitive.
Close ups of this component don't reveal any spots or leg identification markings.

Yeah, without any indication of orientation I would assume then there isn't a specific orientation required outside of the physical shape ie being rectangular rather than square

EDIT: Finally got done soldering in the EM10 (boy that was hard, especially as the person who tried to fix this SP before actually tore off one of the 4 contacts on the board for where the EM8 went!) and it now charges! Woohoo!

Thanks FAST6191!