HBN's SNESp Project

HBN · Post by **HBN** » Fri Oct 10, 2008 7:24 am

Sorry for the double post (Which I wouldn't need to do if people actually posted in reply...), but I need a hand.

I understand that the SNES can be run off 5v, tapped off the 7805 off the back of the PSone/Zenith screen. I've had it explained how to do it. Which is nice, and I thank you. But I don't work like that. I need to see what it looks like. Does anybody have a BMP schematic, or a clear image of this being done? I only have one screen, and one SNES, so make it as clear and detailed as possible so I don't fry one or both of them. I'm a bit freaked at the idea of doing this, as I doubt my skill to actually pull it off. The better idea I have of what I'm doing, the better I will feel about it. I'd like to know ASAP so I can get final wiring done.

Also, my dad seems a bit spooked at using the stock SNES power switch to turn this on and off (Cuz of how its wired, which even I will admit is a little odd.). Which I want to do because I love the feel of it. Is there any reason I shouldn't use this switch? Do I have to do anything special? If so, show me.

lovablechevy · Post by **lovablechevy** » Fri Oct 10, 2008 8:19 am

hope this helps.

HBN · Post by **HBN** » Fri Oct 10, 2008 8:43 am

I'd be using the other 7805 on the board, but it should, yes. Thanks, Chev.

HBN · Post by **HBN** » Mon Oct 13, 2008 7:45 am

A bit of solder, and half a gluestick later:

Its done! Well. Its WORKING. I still need a case (With paint), battery, and I need to hook the screen up to its motherboard. It looks kinda messy right now (Wires...THE WIRES! THEY'RE ATTACKING!!! GAHHHH-*static...death gargle*!!!)

Actually. Can I say its working? I haven't tested (No battery). ^_^. Okay... Rephrasing time:

UNLESS I FRIED SOMETHING ITS WORKING.

^_^. I'll get pics, if y'all show interest. I don't do this for free, after all. Well... I do. >.>...Details...

By the way, Chev, your diagram has a major mistake:

You're switching the ground off the battery. NEVER do that. Ground can come from anyware, not just the battery. You can fry stuff pretty badly that way. If you're lucky, you'd just have the system turn on for no reason other than it just got grounded. ALWAYS switch the hot side (Positive side). But if you can (With a DP-DT, or two SP-ST) switch both. If not both, then always the hot side. NEVER GROUND. I cannot reiterate that enough. Especially knowing the money and effort that can be put into portables. ^_^.

lovablechevy · Post by **lovablechevy** » Mon Oct 13, 2008 7:54 am

HBN wrote:By the way, Chev, your diagram has a major mistake:

You're switching the ground off the battery. NEVER do that. Ground can come from anyware, not just the battery. You can fry stuff pretty badly that way. If you're lucky, you'd just have the system turn on for no reason other than it just got grounded. ALWAYS switch the hot side (Positive side). But if you can (With a DP-DT, or two SP-ST) switch both. If not both, then always the hot side. NEVER GROUND. I cannot reiterate that enough. Especially knowing the money and effort that can be put into portables. ^_^.

umm... no.

many people on this site put the switch on ground.

i'm thinking that ben's book even says to put the switch on ground but don't have it in front of me.

all of my stuff has the switch on ground.

it works perfectly fine. and makes it easier to have the switch tie in to the screen and system.

all that matters is that the circuit is being broken.

Valium · Post by **Valium** » Mon Oct 13, 2008 8:04 am

Batteries work like a chain. Break one link and it doesn't work. If you disconnect the ground from the battery, and whatever you're powering is grounded, it won't keep getting power. The current has to be routed back to the battery via it's ground before it actually does anything.

HBN · Post by **HBN** » Mon Oct 13, 2008 8:31 am

Its your portables. I got 40+ years of experience saying different. Sure, those years are mostly my dads, but hes taught me all I know. And I also know it can happen. I've done it.

But like I said: It's your portables.

EDIT: This is from a site I found with someone saying they were going to switch the ground in a home:

A very bad idea! Not legal and not electrically safe. I'm thinking this
switch is on the far side of a light switch, so the black comes to the
switch and the white is used as a black to go back to the light fixture.
If so, you need to pull a 3-conductor line to provide the neutral.

Don't even THINK about using the ground as a current-carrier.

W. Underhill

Granted, thats talking 120 VAC, not 7.5 VDC, but the rule applies to both. It's a bad idea. Proof enough, or are you still going to argue?

lovablechevy · Post by **lovablechevy** » Mon Oct 13, 2008 8:44 am

HBN wrote:Its your portables. I got 40+ years of experience saying different. Sure, those years are mostly my dads, but hes taught me all I know. And I also know it can happen. I've done it.

But like I said: It's your portables.

considering just how many ppl here have wired it up that way, i'm pretty sure we're all gonna be ok. you just need to break the chain. the battery's ground needs to be connected for the system to power up, not simply some random ground from the board.

Tibia · Post by **Tibia** » Mon Oct 13, 2008 9:57 am

HBN wrote:Its your portables. I got 40+ years of experience saying different. Sure, those years are mostly my dads, but hes taught me all I know. And I also know it can happen. I've done it.

But like I said: It's your portables.

EDIT: This is from a site I found with someone saying they were going to switch the ground in a home:

A very bad idea! Not legal and not electrically safe. I'm thinking this
switch is on the far side of a light switch, so the black comes to the
switch and the white is used as a black to go back to the light fixture.
If so, you need to pull a 3-conductor line to provide the neutral.

Don't even THINK about using the ground as a current-carrier.

W. Underhill
Granted, thats talking 120 VAC, not 7.5 VDC, but the rule applies to both. It's a bad idea. Proof enough, or are you still going to argue?

How do YOU have 40+ years experience anything? Your dad may, but that isn't YOUR experience.

And battery DC current works entirely different from AC current. The reason putting the switch on the ground doesn't work for AC is because the ground only carries power if there is a fault in the system. Putting an AC switch on ground doesn't stop the flow of electricity at all. That's why the switch for AC MUST go on the HOT wire.

Batteries are ENTIRELY different. If there is a break at ANY point in the circuit, whether it's on the V+ OR the ground, the power will not flow. In low-voltage DC applications, it's perfectly safe, as well as standard practice to switch the ground. Many people put the switch on a common ground to turn screen and system on and off at the same time.

Get your damn facts straight before you go around calling people who know what they're doing stupid. You just look worse when you get it wrong like that.

*21 years of MY OWN experience messing around with electronics*

lovablechevy · Post by **lovablechevy** » Mon Oct 13, 2008 10:03 am

HBN wrote:Granted, thats talking 120 VAC, not 7.5 VDC, but the rule applies to both. It's a bad idea. Proof enough, or are you still going to argue?

naw, i'm done. i think i'll let every one else argue with you now.

Rekarp · Post by **Rekarp** » Mon Oct 13, 2008 10:46 am

As an EE major I think i should say something about this subject. It is perfectly fine to break the GND as a form of a switch in a DC circuit. GND in DC circuits are completely different from GND in AC circuits.

HBN · Post by **HBN** » Mon Oct 13, 2008 11:47 am

Tibia wrote:Get your damn facts straight before you go around calling people who know what they're doing stupid. You just look worse when you get it wrong like that.

*21 years of MY OWN experience messing around with electronics*

I didn't call anyone stupid. And frankly, when I've switched ground and BLOWN SOMETHING UP BECAUSE OF IT (People seemed to have missed that I said that, so I'm emphasizing, not yelling.), I don't give a damn about 21 years of experience that says that didn't happen. My dads done it also. And I said it wasn't all my experience, and mostly my dads. But I got a helluva start because he taught me literally all I know. So its experience by extension.

Rekarp. I understand where you're coming from. But I've DONE (Also not yelling) it. Though they are different, the rule still applies. It has in my experience, and my dads. I'm not dismissing your major. I'm saying my personal experience doesn't match it. And personal experience is more powerful, IMHO.

And even if I'm wrong, look at it this way: Ground can come from anywhere. Power CANT (Still not yelling). So, as a precaution, wouldn't it be better to just switch the hot instead? I mean, to each there own, but it just seems to me the smart route would be the cautious route.

Chev. I wasn't talking just to you. it was namely a comment to everybody. Hope I didn't offend you, or anybody else.

Everybody. I'm doing extensive testing now...Hold on for an update within the next hours.

Tibia · Post by **Tibia** » Mon Oct 13, 2008 12:10 pm

HBN wrote:I didn't call anyone stupid. And frankly, when I've switched ground and BLOWN SOMETHING UP BECAUSE OF IT (People seemed to have missed that I said that, so I'm emphasizing, not yelling.), I don't give a damn about 21 years of experience that says that didn't happen. My dads done it also. And I said it wasn't all my experience, and mostly my dads. But I got a helluva start because he taught me literally all I know. So its experience by extension.

And even if I'm wrong, look at it this way: Ground can come from anywhere. Power CANT (Still not yelling). So, as a precaution, wouldn't it be better to just switch the hot instead? I mean, to each there own, but it just seems to me the smart route would be the cautious route.

Oh, so experience by extension counts? From the same dad who didn't want to use the SNES's original switch? Riiiiight. Whatever. At least I've bothered to do my own learning instead of relying on someone else's.

Somehow, I doubt very much you've blown something up JUST by putting a switch on the ground. If something blew up, that means there was a connection being made somewhere that electricity was flowing through. Electricity does not flow through thin air or an open switch.

And no, ground cannot come from anywhere. You're confusing DC and AC electrical terms again. In AC, something is properly grounded when it has a path of least resistance to the earth in case there is an issue with the circuit. In DC, something is grounded when all the ground leads are tied to ONE source, the negative pole of the battery. If you still don't believe me, take an LED and a 3v battery. If you touch just the positive leg to the positive side of the battery, nothing happens. The "ground" must be connected to the negative side. That's exactly why a portable won't work if the screen ground and the system ground aren't tied in together to the negative terminal of the power source. If they aren't, the circuit isn't completed. The power will not flow because there's nowhere for it to go.

There's nothing at all wrong with putting the switch on the positive pole. However, there's still nothing wrong with putting it on the negative pole. It's a matter of personal preference, one isn't any different from the other. That's the only point I'm trying to make.

Do all the "extensive testing" you want, just keep in mind that AC knowledge means very little in DC applications. It's a different set of rules entirely. Don't jump down peoples' throats because they know more than you do about it, especially since they were just answering YOUR question in the first place.

HBN · Post by **HBN** » Mon Oct 13, 2008 12:53 pm

Tibia wrote:Oh, so experience by extension counts? From the same dad who didn't want to use the SNES's original switch? Riiiiight. Whatever. At least I've bothered to do my own learning instead of relying on someone else's.

Lets not insult my dad again, okay? That's the last time I'll say it nicely. The SNES switch is wired weird. Normally, with a SP-DT switch (Which is what it is), you'd solder a lead to the center pole, and to one of the outer poles. The SNES power switch uses both outers, but not the center. In fact, the center has been cut off. Three words:

Welcome to Japan.

That aside, because this isn't a pissing contest, I hit a snag. I tested it, and everything works. But the screen has no picture. The SNES powers up, and transmits the signal to the TV (Tested it with a cord), but I'm not getting anything on the PSone screen. The backlight comes on, though. So its like its not getting the +5v for the RGB circuit. Weird.

Any ideas?

Rekarp · Post by **Rekarp** » Mon Oct 13, 2008 1:10 pm

HBN wrote: Rekarp. I understand where you're coming from. But I've DONE (Also not yelling) it. Though they are different, the rule still applies. It has in my experience, and my dads. I'm not dismissing your major. I'm saying my personal experience doesn't match it. And personal experience is more powerful, IMHO.

And even if I'm wrong, look at it this way: Ground can come from anywhere. Power CANT (Still not yelling). So, as a precaution, wouldn't it be better to just switch the hot instead? I mean, to each there own, but it just seems to me the smart route would be the cautious route.

So every text book and lecture I have been to is wrong? This includes several professors that I know that have written DC Circuit Analysis books? I have taken 2 courses (on my third) that deal with nothing but DC circuit design, I hope I know what I am talking about at this stage.

The way batteries work is that the Positive and Negative (or GND) must be connected for current to flow. If you break a connection somewhere along the line the current will stop flowing. In DC circuits GND doesn't come from anywhere but the negative terminal of the voltage source (in this case a battery).

AC circuits are completely different from DC circuits and have there own set of rules.

My Duop works by switching the GND wire on and off. I usually pick what wire runs closest to the switch.