Fried Famicom

[Rablador]

Hello

I did not check what power supply I stuck into my Famicom (DC) and accidentally fried it with a standard NES supply (AC).

I opened up the machine and discovered that a 1000� capacitor had blown (well, barely, it was still intact). Does anyone know what usually goes first when something like this happens? Is it usually just the capacitor or do all kinds of parts blow?

Also, can this in any way harm the TV? I'm using a new LCD set, so I'm not exactly thrilled at the thought of having to buy a new one. I should add that this Famicom had an AV mod. Is there any possibility that excessive voltage might go through the RCA cables and harm the TV (there was a humming noise when I plugged it in and it was magnified when I turned on the console, well, before it blew anyway)?

[NFG]

Hahaha...

I've done exactly this before.

[l_oliveira]

Hm ....  All you need to do is replace the CAP and the LM7805 chip (if it doesn't power on anymore...)

[kendrick]

A modern LCD TV should have some buffering circuitry (or at very least a fuse) to prevent off-spec input from screwing anything up permanently. The easiest way to test is just to connect another game console with composite output and make sure everything looks right. Typically, you might have to reset the colors and scan size to defaults, and the worst case scenario is replacing a fuse or other blown component. The Famicom by itself is unlikely to generate the type of high voltage or high current that would blow out the video decoder.

[Rablador]

Hm ....  All you need to do is replace the CAP and the LM7805 chip (if it doesn't power on anymore...)

I have looked for the LM7805 chip on the Famicom main board, but I can't seem to find it. What is it supposed to look like?

/Jon

[Rablador]

Oh, nevermind, found it!

There are, however, many different kinds of LM7805 in the electronics stores. Can I use any of them?

[l_oliveira]

Make sure you remove the blown one from the famicom and take it to the shop. Buy one with the same encapsulation as the original. Brand doesn't matter much.

[isodee]

Hi! I just made the same mistake I plugged nes power supply to famicom and guess what happened.....
Can someone give a repair guide... Im n00b so I dont know what im looking to replace? I opened my famicom but dont know what am I exactly looking?

[isodee]

Oh and what is CAP

[l_oliveira]

CAP ? CAP is short for "CAPacitor" not CAPCOM, on this case
more information here :
http://en.wikipedia.org/wiki/Capacitor

[isodee]

LoL I didnt have any idea what you were talking... But now I know!! So when I change those my Fami suppost to work?

[kyuusaku]

Unless something else was damaged before the 7805 broke.

[isodee]

Can I get some pics of the parts because I cant find??? or mayby schematics?

Heres pic of my fami stripped.
http://img512.imageshack.us/img512/7929/dsc00056da1.jpg

[kyuusaku]

Look next to the power jack.

[ken_cinder]

I don't see anything apparent in that pic, could you take a shot of the other side of the board(s)?

Maybe we can spot any apparent damage like a burn point/trace that would help you sort this quicker.
That and I've never seen Fami internals, I just want a look.

[duo_r]

7805's can get fried without any visible damage. Your best bet is bust out a multimeter and bench test with the power board plugged in - just be very careful. Test the input pin, and the output pin (this should read 5V), and have your grounding pin grounded somewhere on the board.

My 7805 looked perfectly fine in another system but it was fried.

[isodee]

I have to go and buy a multimeter and try to find the problem..... and I cant see any visible damage either...

[isodee]

IS IT MAYBY THIS ONE WHAT IM LOOKING??? (sory bout bad quality)

http://img291.imageshack.us/img291/8696/famiivr0.jpg

[duo_r]

that doesnt look like it, but I can't reallly see it. It should be labeled 7805. Also here is a quote from another forum:

...try replacing the 7805 its located on the front side of the small metallic box where you plug A/V RF and Power. Small 3 legged black thingie.

[l_oliveira]

Taken straight from your picture: remove the screw to detach the LM7805 part from it's heatsink. Then de-solder it from the board and take it to a electronic parts shop.

[isodee]

thanks! i will try to fix the fami in upcoming weekend... i read somewehere that pc-engine ac would work on famicon??? can anybuddy confirm am i right?

[l_oliveira]

Actually *any* AC to DC adapter with negative on center pin, voltage from 8v to 12v and current of 700ma or more will work. I would say that 500ma is enough at 12v ... But have a margin for better operation. For information a Mega Drive/Genesis adapter has 1.2amp at 9v and works perfectly with a wide, lax margin.

[isodee]

Finally I got the time to fix the console!!!! So the megadrive power adapter should work (even european version?)

[l_oliveira]

Famicon requiires negative on center polarity and any voltage around 9-12 vshould work ...
I recommend 800miliamps or more as for current.

Megadrive / genesis is 9v/1.2 amp so it's far more juice than it needs. So it should work with large margin.