SNES Power Supply (PSU) Repair - NES-002(GBR)

[DaveJ-UK]

I have 12 of these PSUs that don't work. The SNES just doesn't power up.

I tested one with a multimeter and it is putting out 2.5V instead of 9V. So I had a search online and came across this page:

http://www.sega-16.com/forum/showthread.php?8067-Repairing-a-SNES-AC-adapter

It seemed to be exactly what I was looking for; it is the same model and has a list of things to check. Great. Except when I opened it up there is nothing except a transformer inside - no capacitors, no diodes, nothing else to check.

Am I being thick?

[Fix_Metal]

My PAL snes had DC stuff inside the console itself (bridge diode + cap, no regulators on main DC.). If you're sure you've measured AC and not DC and it's just 2,5V, get a new trafo and that's it.

[DaveJ-UK]

Thank you for the reply.

Do you know what type of transformer it is? Obviously it needs to be 240V > 9V but there are various options on RS Components. Can you point me in the right direction?

[Fix_Metal]

Read the inprint on the transformer case. The power rating is written on that or on the back label of your snes.
Once you know voltage and current needed, you're done. Plus, nowadays trafos are more compact than oldies, so you're going to just change it in the case, solder and ready to play again

[DaveJ-UK]

Yes I understand that it needs to be 9V with a minimum of 1.3A as indicated on the label.

What I mean is that there are lots of different types of transformer; PCB, toroidal, IMO, Chasis Mount, etc.

[Fix_Metal]

A toroidal is just excessive for this application.
I just checked mine and you're right, it's a 1,3A transformer. Didn't think a SNES to be such high power sucker 
Just buy the smallest one 9V 17VA (as labeled, just sawn mine. that's because efficiency is never 100%) power rating. If it has 2x9V (2 secondaries), you can parallel them to get the full current from the transformer (I.e. 2x9V with 2x650mA, you parallel the outputs and get 9V 1,3A). I'd buy one pcb type and glue it in the case with hot glue.

[DaveJ-UK]

Thanks Fix - sorry its been a while.

I have opened up a few more of these PSUs and it turns out that the transformers are OK in the majority of them - it's the cable that is faulty.

A quick continuity test on the transformer output gives a constant tone but at the end the cable gives nothing. So I guess there is a break and a short. Is there any simple way to find where the break is?

I know the obvious solution is to swap the cables over with one with a faulty transformer but I have far more faulty cables than transformers.

[Fix_Metal]

I know the obvious solution is to swap the cables over with one with a faulty transformer but I have far more faulty cables than transformers.

You're right, it's the obvious and fastet solution. Go buy a 2 wire non-shielded/braded cable from your local electronic supply and be happy 'bout it 
If there's no humps nor bumps along the cable, then it's almost for sure broken inside the connector. It's fairly common for cables being joint into connector to fail overtime. This reminds me of those s***y mini din connectors who brought s-video and (unfortunatly) mega drive 2 and sega saturn a/v stuff. They all failed to me.

[ApolloBoy]

Couldn't you just use a model 1 Genesis/Mega Drive PSU though? That's what I use on my NES (which accepts AC just like the PAL SNES) and I've never had a problem.