Home Made A/v Switch Help.

[TJ_Kat]

Since there are a billion* jacks at the back of my TV - and making sure I'm plugging things in the right place is challenging (and it's a pain to make sure s-vid is oriented properly) - I've come to the conclusion that I need an audio/video switch... or two. I have yet to find any commercial versions on the scale/with the functionality I want, so I intend to do it myself.

I've taken apart an OLD 2 port kvm switch I had laying around, and I fully understand the principle of what I want to do. My problem is parts. I have no clue where to get material that will function as (or be made to function as) the plastic discs and the metal contacts that make up the barrel of the switch assembly.

If you know what I'm talking about and know how I could obtain/fabricate these parts, please let me know.

If you don't know what I'm talking about, but still want to help, I can take some pictures and post them.

[size=8]*there are not really a billion jacks on the back of TJ's TV. TJ's cannot be held responsible for any of the less bright people who actually believe there are 1,000,000 a/v jacks on the back of his TV. If you are one of these people, please consider getting yourself sterilized.[/size]

[NFG]

Did you know a billion has nine zeroes, not six?  Unless you're a freaky European, I hear they do things differently.

Don't even try to build your own switch, man!  Buy an existing one and make adaptors for the connectors.  a 9-pin serial switchbox can do Svideo, video and R+L audio with pins left over.  They're also about ten bucks or less.

[Bostich]

Just how many and what types inputs are you needing?  I find it hard to believe that you can't find any commercially available switches to do the job.

I currently have 12 game consoles, CD changer, EQ, VCR, cassette deck, and VB (audio only) hooked up to my TV and/or receiver.  I'm only using 2 switches right now.  I could actually rewire and get it down to 1 switch, but I wanted to leave it open for expansion.  I currently have enough open inputs for at least 5 more game systems.

However, I am about to throw a wrench into the whole system as I start looking for RGB cables which use the dreaded SCART connector.  I say "dreaded" because it seems just about anything dealing with SCART has to be imported from the UK.  (transcoders, switches, etc.)  Which means it's expensive and you get bent over on shipping.

I know Pelican makes a switch with 8 inputs that supports most common connections used in the US.   I've also seen SCART switches with up to 6 inputs.

[TJ_Kat]

Did you know a billion has nine zeroes, not six?  Unless you're a freaky European, I hear they do things differently.

Oops, hehe. It had been a long day *shrug*.

Locally, there is nothing. The BEST I've been able to find does 5 composite or s-video. I'm looking for one that will do 10 s-video, and one that will do 5 component (this includes room for expansion).

And I'd rather build my own because, for all intents and purposes, I already have all the parts I need (except for the switch assembly proper). If I cannibalize my old kvm switch, all I need are some new metal contacts, and I'll have one of them made.

Also, I did look for switches for 9 and 25 pin connections. Nothing local in the price range you're talking about. Ordering was the same after factoring in shipping and duty.

[Aidan]

I hate the rotary switches. I've always found that they tend to get a bit noisy after a while. Personally, I prefer electronic switching, as this can be done automatically and doesn't suffer from the wear that mechanical switches do. That's especially so as the frequencies and number of poles goes upwards.

As for a billion, everyone knows (apart from the Americans of course) that a billion is a million million. That's 12 zeros, not nine zeros.

[atom]

20 bucks at walmart got me a pretty cool swtich box. Pelican (of course) has now taken over the company and slapped their name on it. The switch does Component and S-video, but I dont see you couldnt feed any signal through those plugs. It also has an RF unit that i dont use, but I did once and it sucked.

EDIT: I happened to stroll into Radio Shack today (my girlfriend was in OLD NAVY, BAH) and I saw an A\B data switch for a serial port like Lawrence mentioned above. It was 39 dollars. Thats radio shack for you.

[Bostich]

Well I don't think you're going to find 1 switch with 10 inputs...sooner or later you have to daisy chain.  (if you do find one, be sure to let me know )

Anyways, if you want to see the Pelican switch I was talking about go here:

http://www.pelicanacc.com/

Stupid dynamic pages...no direct link...click Universal, then PL-957 Pro System Selector.  If I didn't already have two 6-input switches when the PL-957 was released, I would have picked one up.  

[Aidan]

You want the following link:

http://www.pelicanacc.com/universal/popup/...lector_pop.html

Few people make decent switches. Personally, I'd prefer to have a switch with two buses, and at least 10 inputs, with the capability to automatically handle daisy chaining.

It hasn't happened, even though there's nothing stopping the technical implementation.

[TJ_Kat]

Personally, I like the rotary switches. I have a digital kvm for my computers, and I don't like it very much (but it does the job, and the price was right)

There is a place locally that can custom order me one, but the price they quoted me was stupidly high.  

[NFG]

There's a big problem using a mechanical switch for a KVM.  Modern computers and OS' including XP tend to freak out when your mouse or keyboard are removed.  In XP it resets your repeat/wait settings on the kb when it's removed.

A digital KVM uses chips to mimic a kb/mouse so when the input is routed to box B box A is still receiving 'kb present' 'mouse present' signals.

Also a rotary switch isn't really a lot safer than hot swapping a device, it's quite easy to blow fuses on the mobo (I've done it) by mechanically removing a device.

[Aidan]

I've had too many rotary switches with reliability problems to recommend them. All it takes is a small amount of dirt or dust in the wipers to play havok with them.

[TJ_Kat]

well, I may have found a solution to the rotary switch problem, but I gotta wait to get some emails back.

In the mean time, on the s-video jack, C and Y each have their own ground. Do these have to remain separate, or can they be combined into a single connection? I'm pretty sure they can, but I wanted to get the confirmed before I start drawing up my new plans...  

[NFG]

You can combine them safely.  At least, I have don't it often without trouble.

[atom]

Yeah, they probably are combined as soon as they go through that little connector. I often use one gound for video and one ground for shielding on my homemade cables.

[TJ_Kat]

*bump*

Since there isn't much I can do with this until I get something to cut the cases with (EVERYTHING else is sitting on my workbench), I decided to rework the wiring diagram so it makes more sense. Doing this, it occured to me, 'if I can combine the 2 grounds from the s-video, Why can't I combine ALL the grounds (from the audio jacks, s-video jacks, component video jack, and the lights)?' This wouldn't hurt anything, would it?

Also, it occured to me, 'do I even need to run all those grounds through my switches? Couldn't I just connect all the ground terminals in the whole device at a single point with no switches involved?'

[atom]

No, you certainly dont have to switch your grounds. Yes, tie them all together EXCEPT your lights I saw you mention. You can tie all your grounds together for audio and video, but don't do it for anything else. Can you imagine sending wall socket power on accident to your video ground? Eesh.

[TJ_Kat]

So, you're saying my experiment to see what happens when you put 110V through a console is probably going to have pretty obvious results?

In my case, I don't think it would actually be a problem because i'm using a 3V wall adapter... I can't see 3V wrecking anything.

None the less, yeah, I knew enough to keep the lights separate =)



Now I want to get an old junky console just so I can run wall power through it... Maybe even something that would let me hook it up to a stove outlet... I wonder if anything would explode?

[phreak97]

using a 3V transformer, you should be fine to combine the ground connections.


a stove outlet is the same voltage but can handle much higher currents.

all youll get is an instant pop and nothing more, at that level, if something is going to blow, itll do it instantly and give you an open circuit.

what's more fun, is plugging in something like a cd-rom drive (open it up and bridge any fuses if you want the full experience) on a variable power source (mine's 4 amps max) set to AC and slowly increase the voltage, keep pressing eject and stuff as you go along.. i did that, it was very amusing. and resulted in smoke coming out for a good 3 minutes after it was switched off.

also, i dont like the idea of a retro console dying for no reason.

[TJ_Kat]

Nope, there's a difference between standard wall outlets, and heavy appliance outlets (ie: electric stover, clothes dryier); at least in my end of the world.

110V comes out of the wall, and a big appliance outlet spits out 220V.

Anyway, so, if nothing explodes "naturally", the question becomes, what could I add to it to make it explode =)

It's also fun to open up a hard drive with a defunct read arm and watch it spark =) Maybe if i up the input there to 220V, and can get the platters to explode... of course, that would probably be really not safe.

What were we talking about again?