The GameBoy Advance SP works, however there's no audio from the speaker, the SP was different from the Advance in that there's no 3.5mm headphone jack either so I can't easily compare/check it.
What're the steps I can take to start diagnosing this and where the problem is? I'm not familiar with using an oscilloscope if necessary, though I have a bitscope one I could try to work out how to use. I'm not seeing any physical problems.
Whats going on here? looks odd..
Hi Christopher,
It looks like U3 (near the directional pad) is the audio chip, but it's custom so no datasheet. However connections near it could be probed to spot the audio signal, but also worth checking supply rails (there may be a separate analogue and digital supply rail), perhaps identifiable by screenprinting on the board of test points or signal names, or if there is a ground plane. In any case, it appears to be the same chip as on the Gameboy Advance (non-SP), so the schematic will likely be very similar. This is the GBA schematic for that area, and the supply rails can be checked plus the audio at LIN, RIN and the SPKOUT pins. There's also pin 12 which is labelled STB with a bar on top, so that could be inverted standby, and would need to be high for the chip to be enabled.
The part that Matt identified as looking odd could be water damage, and might be power related (supply regulation or switching a power rail on or off) so could well be the cause too. It might need some some examination or solder re-melting there, if any corrosion has damaged a join or track. I couldn't find what part it was, I think it says WBM on the SOT23-6 shaped part U7, but my attempts to google for it found nothing : (
