Did I fix this right?

Includes but not limited to: SNES, Genesis, Sega CD, PlayStation 1, Nintendo 64, Dreamcast, Game Gear and I guess the Virtual Boy.

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Super Mulletman
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Did I fix this right?

Post by Super Mulletman »

I took all the external parts off an original model snes (power plug, video plug, expansion port, controller port on main board, and 7805 chip), and I was trying to get it to work. I wired up the 7805 off the board with a collection of C batteries totalling 9v, and ran the ground and +5v into the corresponding points (where the 7805 would have gone) on the main board, which I tested using alligtator clips and bare wire, as the plugs were all off. Unfortunately, no sound came out, though the video worked fine. After about 10 minutes of me trying to fix it, I tried putting 9v into the input lead of where the 7805 would go on the board, and lo and behold, it worked. I noticed it reset each time I put the 9v in, but when I just took it off, the video would continue to work just fine, but the sound would cut out.

Is this safe? I don't have power going into the original plug (or where it would have gone, in the upper-left corner of the board), just the regulated 5v, so I don't know if I should have non-regulated power floating around. Also, I would now have to make the power switch a DPDT (as opposed to SPST), since I was hoping to just use the 5v off the PS1 screen, but since the DPDTs don't cost hardly squat more than the SPSTs, I'll be fine with that. So really, I just want to know if what I did is safe, or if I could just do something else.
nos_slived
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Post by nos_slived »

Try using a diode to carry some of the 5V out back to the input pin. Here is a diagram:
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Just substitute "Screen" for SNES.
I'm not positive that this will work, but triton said that gannon told him to use a similar setup.
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Super Mulletman
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Post by Super Mulletman »

Well I don't think that's going to work exactly. I was hoping to use a regulated 5v off a PS1 screen so I wouldn't have to use a regulator or extra circuitry.
nos_slived
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Post by nos_slived »

If you do that, make sure that you have a 1.5A 7805, rather than a 1A regulator. If you don't do the LED mod, you will definitely need a regulator that can handle 1.5A, and even with the LED mod, the extra flexability wouldn't hurt.
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Super Mulletman
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Post by Super Mulletman »

No, see I'm not using any regulator except one of those on the PS1 screen itself. That and I already did the LED mod.
nos_slived
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Post by nos_slived »

That's the one I was talking about.
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atkafighter
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Post by atkafighter »

I have an older board (revision 1 or 2). Is it ok to desolder the expansion port? Right now i still have the port on and I have had no problems getting video and audio off the board I'm worried if I remove it I would lose video/sound (or both).
Super Mulletman
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Post by Super Mulletman »

You could have started another topic for this, but it is perfectly safe to remove the expansion port, as long as you remove it safely (I know this from experience).
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