K7100 to K7400

da66en

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So I bought one of Chad's minty K7400 without thinking, primarily because I thought I had a K7400 and I could drop it onto my CRT with little effort.

But when I got home I realized I have a K7100, so my current yoke isn't compatible. I was informed that if I get a new yoke/rings then the K7400 should work on my CRT.

Is it worth the trouble, or should I find another chassis that is compatible with my existing yoke? This K7100 is my second chassis and I'm sick of dealing with trying to get it fixed, hence why I went with Chad's minty K7400. The bottom 1/3rd of my CRT is currently having some kind of convergence issues anyways, so the yoke/rings/convergence needs some attention anyways?

Thanks for your help, always appreciative of you guys.
 
Are you sure the yoke from your 7100 isn't going to work? I'm running a 25" K7xxx (7100 falls into this category, I believe) on a monitor that used to have a 7400 on it while the 7400 is out for repair, and it looks fine.

I'm fairly certain that both monitor chassis use a low impedance yoke.
 
Are you sure the yoke from your 7100 isn't going to work? I'm running a 25" K7xxx (7100 falls into this category, I believe) on a monitor that used to have a 7400 on it while the 7400 is out for repair, and it looks fine.

I'm fairly certain that both monitor chassis use a low impedance yoke.

I am not sure of anything. I am just going by what was said to me in the sale thread:

http://forums.arcade-museum.com/showthread.php?t=239877
 
that could very well be right. I think the standard res models U2000 and K7400 use the same yoke. additionally, all those Zenith tubes they came with were functionally all the same, so they should have the same yoke ratings. I think you would land yourself in the trickbag if you were running one of the medium res chassis with it, that you would need a different yoke.

if smalltownguy pulled it off then I think it's ok.
 
FIXED!! it for ya:D

you can use it on the same tube and yoke as a K7000.

i use the same yoke and tube to test 74xx chassis when i need to.

Peace
Buffett

Test, maybe....FIX a 7400....well that's another story :D :D :D

Sorry, had to throw that one in there....smartass.
 
Thanks for your replies.

So the consensus is that my K7100 yoke will work on this K7400. Both are standard 25" chassis. No loss in image quality?

The K7400 has the hor and vert connectors in two different places on the board. Just chop my connector in half?

Thanks, Darren
 
Heck, I can't believe I didn't know that. I've been dying to get my hands on a 7400 series tube/yoke setup so that I could add them to my "I will repair" list. And, now I will!
 
K7100 needs isolation, this K7400 doesn't. So I should be able to plug the K7400 directly to any AC outlet (line, neutral, ground)? Is just line+neutral OK or does it need ground?

Can I can plug the K7400 into the service outlet of my power supply, which is on the back of the power-supply but on the outside of the cabinet?

My power supply's AC cable (going to the wall outlet) only has line and neutral. Then why does the service outlet have a ground prong? Is that right? What is everything in my cabinet grounded to, some kind of isolated ground from the power supplies transformer?

Thanks, Darren
 
Show us a picture of your cabinet's power cord. You SHOULD have a 3 prong plug on it.

Yes, you can plug the 7400 right into the wall, but it's better to just use the existing wiring in your cab. You're not going to hurt anything by powering that 7400 chassis with 120 from an isolation transformer. If anything, it's redundant protection.
 
Show us a picture of your cabinet's power cord. You SHOULD have a 3 prong plug on it.

Yes, you can plug the 7400 right into the wall, but it's better to just use the existing wiring in your cab. You're not going to hurt anything by powering that 7400 chassis with 120 from an isolation transformer. If anything, it's redundant protection.

If needed I can get a picture. The cabinet's power cord is a cheap looking lamp cord with 2 conductors and 2 prongs (line and neutral). There is no 3rd cable or ground prong.

That didn't seem right, and since you are also concerned I will look at it some more.

the power plugs should be different if you're going from a K7100 (K7000?) to a K7400.

This I am aware off. I was just wondering if I could power the K7400 directly from the service outlet of the cabinet's power supply or from another AC socket (like a power strip inside the cab). But in the process of asking this question, I was concerned why my cabinet power supply doesn't have ground.

Thanks for your guys help.
 
Yeah, if you're going to be using a 7400 chassis in a cabinet that was previously wired with a K7xxx monitor in it, your cabinet's power wiring for the monitor will be a 2-pin power connector. The 7400 chassis uses a 3 position molex connector on the chassis' pcb for power. You'll need an adapter cable to plug that chassis in properly.

The adapter looks like this:

IMG_2497.jpg


A few years back I needed one, so I went ahead and bought the parts I needed to make a bunch of them. I have extras, so if you want one, let me know.
 
Yeah, if you're going to be using a 7400 chassis in a cabinet that was previously wired with a K7xxx monitor in it, your cabinet's power wiring for the monitor will be a 2-pin power connector. The 7400 chassis uses a 3 position molex connector on the chassis' pcb for power. You'll need an adapter cable to plug that chassis in properly.

The adapter looks like this:

<PICTURE>

A few years back I needed one, so I went ahead and bought the parts I needed to make a bunch of them. I have extras, so if you want one, let me know.

I do need one of those, I was going to get one from Twisted Quarter (but theirs only has Molex on the K7400 end, yours has a Molex on the other end that looks like will match what I already have from the iso). If you're looking to sell one then PM me and we can work it out through paypal.

On your cable what should I do with the green/ground that is dangling, just connect it to the other grounds in the cab?

Anyways - back to the issue of no ground prong on the cabinet power supply - look into this more?

Thanks.
 
I do need one of those, I was going to get one from Twisted Quarter (but theirs only has Molex on the K7400 end, yours has a Molex on the other end that looks like will match what I already have from the iso). If you're looking to sell one then PM me and we can work it out through paypal.

On your cable what should I do with the green/ground that is dangling, just connect it to the other grounds in the cab?

I left the ground wire as a bare wire - the intention here is to let the end user crimp on whatever terminal they want to interface the pigtail to their cab's specific wiring. Near your hot/neutral feed, there should also be a ground wire going to your monitor's frame. I'd crimp on a loop terminal and screw it to a nearby bolt on the monitor's frame, and just make sure that your cabinet's wiring harness is attached to the same frame.

I've seen others connect the ground wire to their cabinet by using a barrel connector - whatever works best for you.

Anyways - back to the issue of no ground prong on the cabinet power supply - look into this more?


Thanks.

If your cabinet has a switcher power supply, there should be SOMETHING connected to the earth ground post on it. Usually the bottom 2 posts are hot & neutral, and the next post is earth ground. Start tracing wires to see where it drops off. You should have earth ground going from your electrical receptacle, through your line filter, and on to your power supply.
 
Anyways - back to the issue of no ground prong on the cabinet power supply - look into this more?

If I'm understanding you correctly (and I'll be honest....I skimmed).....your power cord/plug doesn't have it's third prong (earth ground). If this is true, nothing in your cabinet is (earth) grounded. And all of your internal grounding is pointless (until you ground the plug).

Edward
 
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