Question about WG K7000 Zenith Tube

[Vilepickle]

I have a tube that I think the red gun is shot on for a 25" K7000 (in a Golden Tee 2k machine). Would any 25" Zenith tube work as a swap for this? The current one is a Zenith.

[behrmr]

With any tube swap you need to make sure that the neck has the same pin configuration and that they yoke is compatible.  Take your meter and check the ohms on the vertical wires of the yoke and again on the horizontal wires.  Match those values to the donor tube.  If they are close then you may be able to simply swap the tubes.  If not then you may be able to swap the yoke and rings from the original tube to the donor tube.  That is assuming that your neck diameters are the same.

[Vilepickle]

Thanks, that's helpful. Any idea if the CR-23 pin configuration was used in normal Zenith TV's? I saw a 25" Zenith on Craigslist for cheap but if my chances are small it probably isn't worth it.

[qrz]

u should be ok with any 25" Zenith tube from the 90's

(i was a Zenith ASC for almost 20 yrs)

others will also work. however, mounting tabs vary and may require spacers to compensate

[Vilepickle]

Thanks, that's good news! I also see a rejuvenator could be a solution but it doesn't look long term...

[qrz]

a successful rejuve depends on the condition of each cathode. certainly worth the attempt
 

always taking a gamble on a used tube .

[jennifer]

    Swapping yokes and rings gets into convergence issues. A rejuve may pop it back to life,(or officially kill it) but if successful, most likely will work for a good long time. 

[lilshawn]

    Swapping yokes and rings gets into convergence issues. A rejuve may pop it back to life,(or officially kill it) but if successful, most likely will work for a good long time.

this...your issue isn't really the pinout of the tube socket... it's going to be the yoke for the horizontal and vertical deflection that is going to be the issue. chassis are specifically tuned to use the yoke that is on the tubes they purchase. the yokes are tuned to the frequency they are designed to sweep the beam at. sure, you can run a yoke that's designed to run at 25k at 32k but it will run hot and will eventually burn out.

a few microhenrys out and your picture is all wonky and impossible to adjust...a few more and it will blow up as soon as you power it up. doing a resistance check as behrmr suggests will be somewhat close, but you really need to measure the INDUCTANCE of the yoke in order to get a proper picture you can adjust. a random tube yoke will not likely be close enough to the original k7000 yoke to work without some absolute dumb luck.

people have had some success with swapping the yoke from your dead tube to the donor tube. but as jes ays, it takes a bunch of messing around to get the convergence aligned back again. plus side is the k7000 service manual on the wellsgardne site specifically has a PDF available for download that outlines precisely what you need to do to converge the tube step by step.

find a donor tube...swap the yoke from the old k7000 tube to the donor tube and reconverge.

this will be your best bet.

[Vilepickle]

I scored this 25" Zenith CRT today for $25. The model is close to my Golden Tee's tube. Do I need to do a yoke swap with a K7191? The manufacture date looks like it's a few years apart.

Original: G-A63ADG25X
New: A63AGD01X

[Vilepickle]

Just answered my own question I think. Yoke connector is giving different ohm readings on the new tube, so I guess the yoke swap is due!

[Tithis]

    Swapping yokes and rings gets into convergence issues. A rejuve may pop it back to life,(or officially kill it) but if successful, most likely will work for a good long time.

this...your issue isn't really the pinout of the tube socket... it's going to be the yoke for the horizontal and vertical deflection that is going to be the issue. chassis are specifically tuned to use the yoke that is on the tubes they purchase. the yokes are tuned to the frequency they are designed to sweep the beam at. sure, you can run a yoke that's designed to run at 25k at 32k but it will run hot and will eventually burn out.

a few microhenrys out and your picture is all wonky and impossible to adjust...a few more and it will blow up as soon as you power it up. doing a resistance check as behrmr suggests will be somewhat close, but you really need to measure the INDUCTANCE of the yoke in order to get a proper picture you can adjust. a random tube yoke will not likely be close enough to the original k7000 yoke to work without some absolute dumb luck.

people have had some success with swapping the yoke from your dead tube to the donor tube. but as jes ays, it takes a bunch of messing around to get the convergence aligned back again. plus side is the k7000 service manual on the wellsgardne site specifically has a PDF available for download that outlines precisely what you need to do to converge the tube step by step.

find a donor tube...swap the yoke from the old k7000 tube to the donor tube and reconverge.

this will be your best bet.

K7000 is a VERY versatile model when it comes to swaps, I have 3 k7000's, a 19" and two 25" models and none of them are running an original k7000 yoke. The only modifications I've had to do to get them to work is changing out the width capacitor which is very simple to do.

Here is the 25" k7000 currently in my cabinet with a tube and yoke taken from a Sanyo TV left by my apartments dumpster. All it took was a width cap change to get it looking right.




Vilepickle, please post the yoke readings on for both the original and new tube. The tubes themselves are compatible (http://tubular.atomized.org/) and there is a very decent chance the yoke will work if the readings are within a couple ohms of each other.

[Vilepickle]

Tithis,
My Horizontal ohms are right around 1.4 - 1.5 for each yoke. The veritcal is off though, on the original it is 10 ohms and the new one is 4.5 ohms. Is that close enough? I'm guessing the chassis would drive the new yoke too hard since the resistance is less but if that's close enough it'd save a lot of trouble.

[Tithis]

Looks too low on that vertical :/ 6.5-13ohms is typically the range you are looking for.

Buffet says he has a few factory k7000 yokes that are only 5.1 on the vertical, but that seems far from typical.

Yoke swap isn't as difficult as some make it out I found. One point I didn't see mentioned here is don't swap out the purity rings when you swap the yoke. The rings are already setup for the tube, it's one less thing to adjust if you keep them. Most of the time they are marked with some white paint, once you swap the yoke just put the rings back into their original position.

[Vilepickle]

So I went to try out my rejuvenator on the tube. When I was attaching the universal connector, I realized one of the pins was broken off my tube! This hastened my decision to tube swap, so I did so with the old yoke.

New tube has the correct brightness, but I'm totally missing red still. It sort of leads me to believe the red in this Golden Tee machine is not right, as I had this chassis plugged into another game and I saw red.  Since it's not my chassis or tube anymore, I'm not sure what to do at this point... Checking the JAMMA harness and connectors, red is hooked up right.

When I use the red pots, my screen background turns a little red, like it's being "forced" on the tube, but the screen test and game show absolutely no red.

I feel like I'm getting close to having a working monitor here, but it's been frustrating

Here's an image of this new problem, and also I haven't done any real convergence fixing yet after the swap.

[jennifer]

   Did you rejuve the new tube?, My guess the red gun is shorting out or failing... A good pattern gen. (the leader 400, my personal favorite) can turn the colors off/on multiburst, and do multiple screen tests. awesome for this kind of thing, much more control over that on board test. 

[lilshawn]

give the jamma harness where it plugs onto the board a wiggle. a bad connection there can cause a dead color.