FamicomBox

[MegaManSec]

Hey everyone..

I've got a FamicomBox here, but the PSU seems to be shot.

When turning it on, it blows the fuse within the PSU, and requires it to be replaced.
My question is simply.. what could be wrong with it?

I tried my friend's PSU on mine, and it works fine.

Here's some pictures:
https://imgur.com/hmpY4Ej,CXLGwHZ,UGU61 ... 1W,d778tsY

Pic one is the whole thing(unplugged, though)

2 is the transformer part w/ down-converter i guess.
3 the same.

Now, 4, is the 'front unit'. On the left, is where you connect it to the socket.
On the right is where it goes 'out'. So that's where a 5V connection goes out.
The middle is something else completely.
That's if you want to plug something else into the socket, like a TV, to save space. You'll see what I mean later.
Pic 5 is the same, but a different angle. You can see where the fuse goes.

On pic 6, there's a 4A fuse which is only used those 2 outputs on there. And that doesn't blow, so that's fine. That's not even used, really.

Now, on the left, you can see the 'output' cord, where it outputs 5V 5A.
And on the right, "AC IN 100V".

And picture 7 and eight are is my makeshift PSU I'm using.



When I bought it, it was apparently working(with a picture of it working)..
So I'm thinking perhaps whilst it was shipped, something could have been knocked out of place.

Originally when I plugged it in, I didn't use a downstep converter... So that could have done something too? Perhaps blown a cap? (Very stupid thing to do, I know.)
Luckily it had the fuse in there, orelse the whole thing could have blown..!


I also made a makeshift PSU with a computer PSU by cutting an HDD power cable - http://s.eeweb.com/members/extreme_circ ... 818559.gif and powering the [broken] PSU straight from that, bypassing the fuse part..
It worked well, for the time being..

[danntor]

By passing a fuse is just stupid to be honest. Now that that is out of the way it could be a whole lot of things. If something does not work like this, always put it through a ultrasonic bath first taking care not to clean components that have lacquer on it(for example the 2 transformers in there), conformal coating is fine but this does not have any by the look of it. Always check the things most likely to fail(they also tend to be more complex). Fuses, ICs, diodes, electrolytic capacitors. Just to clarify, the Famicom Box is being powered by the makeshift PSU(nothing from the original power supply is being used)? You would notice a blown cap from the smell and a distinctive bulge in the top(it is why they have the segmented part on top).

[lidnariq]

Originally when I plugged it in, I didn't use a downstep converter... So that could have done something too? Perhaps blown a cap?

Are you in 240V or 120V land? I'd be surprised if the difference between 100VAC and 120VAC would have been big enough to matter, given the topology of this power supply.

First things first, though: What does the big transformer do? How much voltage does it put out? Any other obvious printing on it? Right now I'm going to tentatively guess it's a 16VAC center-tapped transformer output, arbitrarily based on the model number. Does the fuse blow with only it plugged in, and not the secondary switching power supply board?

If the transformer, in isolation, blows the fuse, you'll have to replace it. (Unfortuantely. It's more or less completely not serviceable and usually fairly expensive) At that point, replacing the entire power supply might be better.

[MegaManSec]

By passing a fuse is just stupid to be honest. Now that that is out of the way it could be a whole lot of things. If something does not work like this, always put it through a ultrasonic bath first taking care not to clean components that have lacquer on it(for example the 2 transformers in there), conformal coating is fine but this does not have any by the look of it. Always check the things most likely to fail(they also tend to be more complex). Fuses, ICs, diodes, electrolytic capacitors. Just to clarify, the Famicom Box is being powered by the makeshift PSU(nothing from the original power supply is being used)? You would notice a blown cap from the smell and a distinctive bulge in the top(it is why they have the segmented part on top).

The bypassing of the fuse was purely to turn it on to test!
But it was going through the same sort of cable, so it should be fine anyways.

As much as I would love to have a ultrasonic bath, I don't.

The 'makeshift PSU was 99% non-original, but purely just that front piece to turn the 2 wires into the tubular input/output.


I just noticed this: https://i.imgur.com/eHcUSlo.jpg
Thge big transformer is leaking(?) some sort of acid or something.. I'm not sure.

But, I don't see any bulges in the caps. So they might be all good.

I'm unsure as to how I can test whether it works without it being plugged into the second board, because it only turns on when I plug it in.. Perhaps you know a way to 'jump-start' it?

EDIT: Ooo, I'm wrong. it turnson without being plugged in.
I'll debug it now!!

EDIT v2: Yes, you're right.
When I plug it plug it all in, but don't plug the outbound transformer(red,blue,red) into the second board, it doesn't blow the fuse.
But when I plug it in, it does -- Even if I plug those two black cables into the plug next to the orange/black cap. So it must be either the transformer(?), or something on the second board.
Although this is bad news, it's also goo dnews. I'm making progress!!

What should I do now?

Originally when I plugged it in, I didn't use a downstep converter... So that could have done something too? Perhaps blown a cap?

Are you in 240V or 120V land? I'd be surprised if the difference between 100VAC and 120VAC would have been big enough to matter, given the topology of this power supply.

First things first, though: What does the big transformer do? How much voltage does it put out? Any other obvious printing on it? Right now I'm going to tentatively guess it's a 16VAC center-tapped transformer output, arbitrarily based on the model number. Does the fuse blow with only it plugged in, and not the secondary switching power supply board?

If the transformer, in isolation, blows the fuse, you'll have to replace it. (Unfortuantely. It's more or less completely not serviceable and usually fairly expensive) At that point, replacing the entire power supply might be better.

I'm in 240V land.(Australia).

No idea what the transformer does, sorry! Here's a clearer pic of the top: https://i.imgur.com/oxpzW1Y.jpg
Also, see this: https://i.imgur.com/eHcUSlo.jpg

Assuming it is the transformer, it would most likely be cheaper to buy a new one. As the only way to get another power supply would be to buy another Famicombox(or a Super Famicombox).

[danntor]

An easy way to test the transformer is to take your one out of circuit by desoldering it and taking your mates one out as well and measuring the resistance across the output. Compare the outputs of the 2 and tell us what you get for both.

[MegaManSec]

An easy way to test the transformer is to take your one out of circuit by desoldering it and taking your mates one out as well and measuring the resistance across the output. Compare the outputs of the 2 and tell us what you get for both.

No need for desoldering, it is just screwed in(unles you mean something else).

I'll get the output of mine now, and I'll ask my friend to test his.

[danntor]

An easy way to test the transformer is to take your one out of circuit by desoldering it and taking your mates one out as well and measuring the resistance across the output. Compare the outputs of the 2 and tell us what you get for both.

No need for desoldering, it is just screwed in(unles you mean something else).

I'll get the output of mine now, and I'll ask my friend to test his.

Did not even notice the plugs. Just unplug both plugs from the sockets so you don't get resistance from the whole circuit added in.

[MegaManSec]

An easy way to test the transformer is to take your one out of circuit by desoldering it and taking your mates one out as well and measuring the resistance across the output. Compare the outputs of the 2 and tell us what you get for both.

No need for desoldering, it is just screwed in(unles you mean something else).

I'll get the output of mine now, and I'll ask my friend to test his.

Did not even notice the plugs. Just unplug both plugs from the sockets so you don't get resistance from the whole circuit added in.

Think you could circle as to where I put the two points of my multimeter? https://i.imgur.com/PdU9Orn.jpg

And which one do I use?: https://i.imgur.com/VykHAS8.jpg


Sorry for my complete ignorance.. I'm not really into this side of electronics.. I much prefer the code side

[danntor]

For the multimeter settings, put it to the bottom right setting, the group in green with the horseshoe looking symbol(an ohm by the way, the SI unit for electrical resistance). Start from the top (2000K) and work your way down until it stops saying OL(overload),MAX,etc. If you get all the way down to 200 and it reads close to 0, that indicates a short. As for where to put the leads, use the black and white by themselves or use the bottom 3 in pairs(ie middle to right red, middle to left red, left red to right red). Make sure you and your mate use the same scale for comparing or note the scale. 1 ohm is close to a short(very little resistance) but 1 kilo ohm is 1000 ohms(it would show as 1K). Sorry for simplifying it so much but I don't know your level of electronics theory mate. I suck at programming but love the electronics part.

EDIT 1: You should only need to do black and white, but it helps to cover all bases.

EDIT 2: Multimeter settings

[MegaManSec]

For the multimeter settings, put it to the bottom right setting, the group in green with the horseshoe looking symbol(an ohm by the way, the SI unit for electrical resistance). Start from the top (2000K) and work your way down until it stops saying OL(overload),MAX,etc. If you get all the way down to 200 and it reads close to 0, that indicates a short. As for where to put the leads, use the black and white by themselves or use the bottom 3 in pairs(ie middle to right red, middle to left red, left red to right red). Make sure you and your mate use the same scale for comparing or note the scale. 1 ohm is close to a short(very little resistance) but 1 kilo ohm is 1000 ohms(it would show as 1K). Sorry for simplifying it so much but I don't know your level of electronics theory mate. I suck at programming but love the electronics part.

EDIT 1: You should only need to do black and white, but it helps to cover all bases.

EDIT 2: Multimeter settings

Ok, here we go:

On the multimeter, on the '20K' setting, putting the red multimeter cord to the white cord on the transformer, and the black to the black, it gives 0.01.
Actually, on all of them it gives 0.01.
Is there another way to test it? Like turning it on, and somehow plugging it into something else? Or measuring the output?

Edit: Measuring the 'A - ...' on '200 µ', I get around 6.

[lidnariq]

That brown stuff isn't a problem; it just paint-on insulator.

If it doesn't blow when the only big transformer is plugged in, the big transformer should be ok.
It'd be nice to find out what your multimeter said when it was measuring red-to-red and (either red)-to-blue. (You'd set the multimeter to 200VAC). I'm guessing 32VAC and 16VAC respectively, but it might show higher if your multimeter doesn't do true RMS, or if it's a 100VAC transformer instead of 120VAC. But all of that should be academic: it doesn't blow the fuse when only the transformer is plugged in.

So I'd start checking everything on the secondary board. There should be a couple diodes, although I can't see where. Maybe the left device on the heatsink? Make sure the capacitors aren't shorts (set to 200Ω resistance and red to +ve, black to -ve which is the side with the stripe) and wait a while to see if the capacitor charges by making sure that the resistance indicated slowly increases.

If you can tell us part numbers off the ICs, that would be helpful.

[danntor]

0.01 on the horseshoe looking setting. Shorted transformer which is causing more current to flow and blowing that fuse.

EDIT 1: What about your mate's reading? This more for people who find this thread. You will need to get a new transformer by the sounds of things but doing a quick parts look I cant find any details on that transformer mate. Famicom Box schematic power supply (most combinations of that) may yield something but I have not found much.

[MegaManSec]

That brown stuff isn't a problem; it just paint-on insulator.

If it doesn't blow when the only big transformer is plugged in, the big transformer should be ok.
It'd be nice to find out what your multimeter said when it was measuring red-to-red and (either red)-to-blue. (You'd set the multimeter to 200VAC). I'm guessing 32VAC and 16VAC respectively, but it might show higher if your multimeter doesn't do true RMS, or if it's a 100VAC transformer instead of 120VAC. But all of that should be academic: it doesn't blow the fuse when only the transformer is plugged in.

So I'd start checking everything on the secondary board. There should be a couple diodes, although I can't see where. Maybe the left device on the heatsink? Make sure the capacitors aren't shorts (set to 200Ω resistance and red to +ve, black to -ve which is the side with the stripe) and wait a while to see if the capacitor charges by making sure that the resistance indicated slowly increases.

If you can tell us part numbers off the ICs, that would be helpful.

Which is VAC? v~ or the other one?

[lidnariq]

V~

[MegaManSec]

V~

In both red's(whilst it's on), it ranges from 0.3 up to 22.0
One in red, one in blue, ranges from 14 to 5.

This is by pushing the points into the 'back' of the sockets.. So I don't know if this is the rightway.. probably not... So take numbers with a grain of salt.


Hee's some pictures of the 'second board'.

(pic from my friend: https://i.imgur.com/UGU61xC.jpg)
Pics from me: https://imgur.com/DM39fer,uHBEf8t,x97Lx5a,JqBBuQU