Having an issue with a PAL N64 power supply (240v, Australian)- have tried it on my PAL and Japanese N64s and no luck (240v and 100v doesn't matter since both machines only draw DC voltage, so the PSU is interchangeable). I've pulled the PSU apart and have run continuity tests on the AC cabling to the PCB and all looks good. I've also checked the three fuses (one large 250v fuse labeled F101 near the AC input, and the two smaller fuses near the DC output labeled F201 and F202), and these checked out for continuity also. I then plugged it into power and tested the outputs - there's nothing on the +3.3v output (resolved to 0v; only tested one of the pins since they're connected) and my multimeter measured +0.1v on the +12v output. I'm not sure if the N64 PSU uses a sensor of sorts to determine voltage output if it's under load and only output accordingly (therefore invalidating the above tests), and since the pinout doesn't include provision for a sensor line (like a PC PSU) that's about all I have at this stage. I've taken a visual look at the caps and they all seem fine, and there doesn't appear to be anything visually awry with the components. Everything looks pristine and shiny, and I couldn't see any weak solder pads on the bottom of the PCB. Any thoughts on how to troubleshoot further? Last I looked PAL N64 power supplies go for silly amounts of money (seems the N64 is popular with the newly retro locally and I'm not enough of a crazy N64 enthusiast to drop money on something I can potentially fix), so I'm hoping I can repair this one. I can confirm it used to work fine on both consoles 12 months ago when I last powered them on
I don't have a PAL PSU here to check, but I can confirm that a Japanese N64 PSU will produce output voltages without being connected to the console - the 3.3V was quite high (about 3.5V) and the 12V was about 11V.
Thanks for that Trimesh, I imagine something's up with mine then. I went poking with the multimeter to trace it back and work out where something's going awry. Since the PSU needs to output +12v and +3.3v, at a guess I figure it must go through something like this (apologies for how basic this is): AC input >> DC voltage >> +12v/7812 regulator >> +3.3v/7803 regulator Or: AC input >> DC voltage >> +12v/7812 regulator and +3.3v/7803 regulator ... Okay, I got half way through my response and started tracing back the DC voltages from the connector and I happened to have the PSU upside down and was testing on the little PCB that has the socket on, and I'm getting +10v and +3.5v. I re-assembled and tested with it the right way up, and nothing. I then flipped it over (still fully assembled), and I'm getting voltage readings. Weird. I then hooked up each console, and the LED power light is now coming on regardless of which way it's flipped, but nothing would come in screen. I found after powering it on, then off a few times, eventually the console booted and ran a game. I've now got both consoles working, but I have to power on/power off a few times to get it working. What was interesting is that when the console is running, I can hear a sound out of the PSU that sounds like a small electric arc/buzz/spark. When the console is off, there's no sound from the PSU, so I imagine as it goes under load that the draw is causing some pressure somewhere in there. For some reason, this behaviour to me suggests that recapping the PSU might assist if the capacitors aren't regulating the flow of voltage correctly, hence having to power on/off a few times, possibly in order to get enough flow through the components maybe? Mind, I'm a newbie so I might be barking up the wrong tree. As it is, while it's working I'm not comfortable using the PSU until I've resolved the issue given that arcing noise. Would anyone be able to suggest if a recap is worth a shot? Or does the above suggest I should be trying something different?
On the Japanese PSU, the +3.3V and +12V are coming from separate windings on the transformer - the regulation seems to be on the +3.3V, and the 12V presumably just tracks it. The design looks pretty conventional - the biggest problem is that about half the circuit is connected directly to line voltage, so it's a bit iffy to work on it unless you have an isolating transformer. You could try replacing the caps, although to be honest I haven't seen many problems with them in Nintendo PSUs
Thanks for your feedback man, really appreciate it. Went to fire up the N64s today and same problem as before - no activity. This time I plugged it into power and started tracing back through the PSU, and I don't think a recap will have any effect since most of them seem to be on the DC side and the regulators aren't getting anything going into them from the transformer from what I can see. I managed to hook it up to one of my N64s with the top of the PSU off, and after a while I was able to get it to load. When a game was inserted I heard that ticking/arcing noise again, but couldn't track it down with my ear. I had a brainwave and used the voice memo utility on my iPhone and ran it over the PSU in various spots to try and isolate the noise, and I can confirm it's definitely emanating from the transformer (labelled BM116A 793G1), as it's showing up on the visual display when the mic on the phone is on top of the transformer. I've done a quick Google and couldn't find anything under the BM number, but I was thinking that one of the things I did between testing and finally finding it would power on was removing the larger AC fuse and putting it back in again. It was probably coincidence, but would this errant behaviour be related to a faulty fuse, and if the AC input is out of whack this might be the cause of the issue? I always thought fuses behaved in a binary fashion - on/off - but thought I'd throw that into the ring. I'll let the PSU rest and will try firing up the N64s during the week, and if they don't work I'll remove/put back in the AC fuse and see if this helps. If so, it should be an easy fix. Otherwise I don't think the transformer's an easy fix, so I might need to put this into the "too hard/cbf" box and find another PAL PSU. Either that or create a custom PSU, but I think my theory is too simplified/hacky to work (grab a 12v switchmode PSU, split the positive voltage off to a 7812 and run that to the +12v pins, then get a 7803 and run that to the +3v pins).
Alrighty, looks like my fuse theory was all sorts of crazy. I took a look on eBay and found this third party power supply, so I reckon I'll grab one of those - has anyone else tried them in the past? Thought I'd check just in case I'm buying a dud.