Technical and Repair Assistance

[ericj]

If you've already ruled out bad AV cables and a bad TV, then you'll have to get the special bit and take it apart.

EDIT: Do you mean an AV-modded original Famicom, or an AV Famicom?

[P]

It must be an AV Famicom as a normal famicom has normal philips screws.

Look for a special bit usually called "gamebit" for your screwdriver, there are 2 sizes (3.8mm and 4.5mm) and they are used for many consoles. You will have too google it though.

Also make sure it is long and thin enough to be able to reach the screws.

[ericj]

I believe the cables aren't properly connected to the console (not an expert on the matter, TBH) and need to be soldered to it again.

^This is what confused me. I think I know what he meant (cold solder joint), but that isn't necessarily what he said by saying the "cables aren't properly connected." He probably meant "the female RCA jack may not be correctly connected (broken solder joint/connection) inside the console." See the difference?  Otherwise, correctly connect the AV cable or try a new one. And yes, I agree about the regular screws on a normal Famicom, unless someone replaced them with different screws.

[Cheetahmen]

It's an AV-modded Famicom. I can't open it because the modder added an extra screw which requires the Gamebit. When I get that, I might be able to elaborate on the problem.

[ricky]

hi famicom world 

i'm hoping someone maybe able to help me as i'm pulling my hair out, i recently got given a famicom and i have a pal tv, i tried the av mod but i'm not getting any audio or video, i'm getting the right voltage to the mother board and 5v at the chips but nothing not even buzzing from the speaker, is there anything i can try?

the mother board is a hvc-cpu-07

many thanks in advance 

[Cheetahmen]

Now that I've got my Gamebit, I managed to open the Famicom to see what's wrong. Not much from what I've noticed, and I certainly can't tell what the problem is. I'll post these photos in case they're any help.

Spoiler

[close]

Edit: I have no idea how it happened, but when I put the cover back on the sound started working again. I suppose I won't need any more help.

Edit 2: OK, apparently putting the screws back in managed to mess it up again. I'm confused.

[ricky]

@ cheetahmen - could be pressure on the wire, while the backs off with the famicom on with a game in press lightly on the black part of the red and white wires.
Post Merge: June 02, 2011, 12:50:44 pm
i have checked the chip voltage again and its nearly 7 volts on all of them, the voltage regulator is also outputting 7.1volts, not sure what i did wrong before   is the voltage regulator duff?

[Cheetahmen]

@ cheetahmen - could be pressure on the wire, while the backs off with the famicom on with a game in press lightly on the black part of the red and white wires.

So how would I able to fix that? Re-solder the wires to the console or something?

[ericj]

Could be the voltage regulator (what is the number on printed on it?), or it could be your multimeter. They're cheap, so you might as well replace it.

More than likely the intermittant sound is a bad solder joint or a broken wire in the RCA cable.

So how would I able to fix that? Re-solder the wires to the console or something?

Replace the RCA cable with a new/different one. But, I'd check the solder connections first--one of them looks suspect from your pics.

[Cheetahmen]

So how would I able to fix that? Re-solder the wires to the console or something?

Replace the RCA cable with a new/different one. But, I'd check the solder connections first--one of them looks suspect from your pics.

Would that be the connection with the red and white cables? That one doesn't look quite right to me.

[ericj]

That's the one I was thinking of, but it would be a good idea to check them all.

[Cheetahmen]

Will do. Of course, it's finding a soldering iron that's the problem.

[ricky]

Could be the voltage regulator (what is the number on printed on it?), or it could be your multimeter. They're cheap, so you might as well replace it.

part number is lm7805, just tried it with another meter and its 7.1volts again  

[ericj]

Are you checking the correct leg and using the right setting on the dmm? If so, replace it. It should be 5v.

[ricky]

Post Merge: June 04, 2011, 06:21:15 am
right i replaced the voltage regulator and have audio and video with the av mod   slight problem i have now though is i have quite bad jail bars, i'm using a bc548b transistor and i am missing the 75 resistor from this plan, they didn't have any in stock but have ordered some from ebay,