GBA SP power issue displays only red light and lasts 20 minutes

[alemesahero]

Dear everyone, I have an issue with my gba sp model AGS-001.

I try to give you a bit of context because I tried a lot of different approaches to solve my problem but they didn't work.

My console has only stock components, it's not modded. It's my childhood gba and I was its only owner. It was left unused in a drawer for roughly 10 years. I used and kept this console with great care. Inside there are no dirt build ups but I still cleaned everything with IPA.
When I tried to boot it it flashed on and off and didn't work. After charging the battery, until the orange charging light turned off, the console would boot up with a red light only and would last on for 20 minutes and then would shut off as if the battery was dry. I then changed my OEM battery with a new one I ordered online with great reviews (uwayor brand) and with another one I had lying around (aftermarket) but still after "completely" charging both batteries, the console would boot up for only 20 minutes displaying red light and then shutting off.
I checked a lot of components for continuity (fuses f1 and f2, em1,2,3,4,5,6,7,8, some resistances, diode d1) but all show continuity. When the charger is plugged in, the battery terminals get 5 V, so charge correctly gets to the battery. I opened the power switch cleaned it and reflowed all its pins with fresh solder, as well as the charging port and em8 (since I found that some people by simply reflowing this "power regulator" solved their issue). Of course I also tested another charger but didn't get any success, this one is aftermarket and apparently my tester reads that it only outputs 2 V instead of 5 V.

I now come to you to ask for help if you have any suggestions for me. I really don't know what could be wrong with this gba. Should I test capacitors? If so, how? I don't have a lot of experience in this. Btw, during the 20 minutes of use I get from the gba it plays games perfectly and sound comes out perfectly as if the console was new.
Moreover, the board looks clean and doesn't show any sign of damage (corrosion or liquid damage), moreover it looks like the traces show no sign of interruption.
Could it be component U5? If so how do I test it?

I'm a bit desperate over this gba because I tried to fix it many times but didn't succeed. Any help from people that have more experience than me is greatly appreciated, thank you very much
Have a nice day

 

[dusk_atl]

Was just about to make pretty much the same post, I have a regular GBA, I've done almost all you have and it either turns on for 20 seconds and shuts off or just rapidly resets as soon as it's powered on. Bumping so that hopefully someone who can help sees this, was really excited to IPS mod it

 

[FAST6191]

I would still be on you got unlucky with replacement batteries -- third party efforts were never great and they might also have been sitting in a drawer for many years. The symptoms do appear to be those of bad battery, and you seemingly have eliminated the other causes (that it charges and allows you to try again saying most things there). If you are going to get radical you might be able to do some kind of deep discharge recovery type operation which I very much doubt the GBA has onboard (is not always a feature seen even today and super rare back then, Nintendo also being able to sell you a new battery if you were negligent enough to get it into that state during warranty period).
Do also bear in mind you will want to do it for the older type of lithium technology most likely (4.2 as opposed to 4.3) which if nothing else will change the management chip you get in to do it (some will offer it as an option, you can however do it with a decent lab power supply, some kind of temperature measurement most likely and resistors but I don't know the suggested protocol so will leave that as a research exercise).

You asked about capacitors and while it is unheard of for things to trouble you as far as specifics or known cases there is the general electronics world that notes it as a general possibility* and time in general offering weird and wonderful faults (saw a clock crystal fail not so long ago as a first).
The traditional thing people measure in testing capacitors is ESR (equivalent series resistance) which needs its own meter -- it is super rare to see it on a normal multimeter (anything you get on on those of will typically just be a Farads tester to measure a fairly basic capacity, which a bad capacitor will still show possibly to its specified level) though I do see weaker ESR meters as part of "component identifiers". They work by sending high frequency AC waves through the circuit which both dodges the capacitor itself charging and throwing results and also being in circuit. With a suitable reference to compare against (working fresh off the floor device is nice but ones in the same system and the ranges are generally well known for given capacitor technologies for a given meter).

*most failed capacitors tend to be either the electrolytic cylindrical variety (especially from the capacitor plague era, the GBA not particularly using either) or something in the serious power aspects of the circuit. The former in 99% of cases are also fairly visually obvious (bulging tops or spilling their guts).

 

[Jayro]

I'm willing to bet the power switch could also be dirty, but your battery issues are either poor battery quality and bad luck, or your caps are bad.