SNES Jr Powers Sometimes, Freezes Seconds Later

[jinxmitchell]

I have a SNES Jr that I've having issues with and I'm hoping someone here can recognize the symptoms. It doesn't turn on all the time, but whenever I flick the switch it makes a noise via the TV, and every now and then it will actually fire up and work. When it does work it will play for a while but if I play in a controller and start playing the game, it only lasts seconds. Also, the reset button doesn't work.

Here are my ideas: The power switch is not making a good connection so using a controller pulls too much power, and maybe the reset button uses too much power to function; or the power port isn't making a good connection with the AC adapter pin with similar results; or the fuse sort of blew, but not completely.

I tried testing with equipment, but I couldn't get any read on anything, even when it was powered on. I'm pretty sure that was because my equipment was meant to read stronger currents than the SNES puts out, OR maybe it helps to support my above theories (it's only getting partial power).

[Ziggy]

Are you sure the console and carts don't just need a good cleaning? The SNES mini has no power indicator light, so you wont know (unless you're probing it) if it's not actually powering on or if it's just not booting the game due to dirty contacts.

What equipment do you have? Just get a cheap multi meter so you can do some basic tests. This is my favorite cheap multi meter, and lots of hardware stores carry that brand. Otherwise, get a cheap Craftsman meter.

I'm pretty sure the fuse can't be partially bad. It's either blown or it's still good. Check the continuity of the fuse to see if it's bad or not. My guess is that it's good because your SNES will still (even if just sometimes) power on.

Test the power adapter, make sure it's supplying the correct voltage. If it's a third party power adapter, check the output specs to make sure it's useable. Nintendo's (NTSC-U) SNES power adapter outputs 10v 850mA. While checking the voltage, play around with the wire to check for bad spots.

If you think the power switch itself is acting funky, that's easy enough to test. You can do it a couple of ways. Remove the PCB from the console shell so you can get at the underside of it. The power switch is mounted on the PCB, so you'll need to get at the bottom of the PCB to probe the switch contacts. Check continuity of the switch in both positions. It should have continuity in one position, and none in the other.

Whenever you do something inside the SNES, make sure you disconnect the power from the console and turn the power switch ON for a full minute before doing anything. Of course, this wont help if your power switch is faulty, so just be extra careful. Check the fuse often, they can blow easily.

But this really sounds like dirty contacts, I would check that before anything else. Give the console's cart slot a good cleaning, and clean the pins on every cart.

[jinxmitchell]

The power supply runs my original SNES, which is something I forgot to mention.

The TV goes to a black screen when the cart won't play, but I'll try cleaning the pins of the system anyway just to be sure. Will post results here later.

[Ziggy]

The TV goes to a black screen when the cart won't play

Yep. That sounds like dirty pins to me.

When you post your results, be sure to tell what method you used to clean the cart slot and the carts.

[jinxmitchell]

Sorry, I didn't complete my thought in that sentence so it didn't actually say what I meant to say. The screen goes black for a split second, then goes white again (the color my analog to HDMI converter displays with no signal), or when it fires up but the cart isn't seated properly it goes to a black screen like I would expect a healthy system to do.

I just tried cleaning the pins to no avail. The method was 600 grit sand paper folded twice and inserted in and out, followed by an old ID card wrapped in a t-shirt and alcohol and finished with a few blasts from an air duster. The cart works on my other SNES.

If this system doesn't get fixed it's not the end of the world, it's just that I've never owned a mini SNES before and I thought it'd be fun to have one in my room with the old style one in the living room.

I'm going to pick up a couple of tools tomorrow (the multimeter you recommended and a desoldering tool since I lost one somehow), and that will allow me to run better tests and remove the power switch to take a look inside of it.

I'll post results when available, and thanks for the assistance.

[Hobie-wan]

Have you tried a plain old composite connection? The convertor might not be happy with the 240 signal.

[jinxmitchell]

The converter works for my other SNES, Gen, and NES, but composite straight to my TV doesn't work. I also tried it on the CRT out in my garage.

[ApolloBoy]

Maybe try reflowing the solder joints on the power jack?

[jinxmitchell]

Maybe try reflowing the solder joints on the power jack?

Can't hurt. I'll give it a shot tomorrow. I tested the 7805 and it seems fine. 9v on one side and 5v on the other. The C58 didn't do squat when I tested it though, so I'm gonna replace that tomorrow.

I'll throw some solder on the connection for the power jack first, and if that doesn't work I'll go on to the C58.

Edit: haha Just ran that logic through my head. If things are testing ok then the solder won't do anything. Hopefully it's just the C58. I looked all over to see what it should test at but haven't found anything yet.

Update: My local Radio Shack doesn't have what I need so it looks like I won't have the things I need til next week. Ordering a 7805 while I'm placing an order anyway.

Update 1-29-13: Replaced the 7805 and C58 with no new results. Gonna tinker with it later.