k7000 tube swap, help with issue

ThomasM

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Donor 2016
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Hi - I've done a few tube swaps, but this one seems to not be playing nicely.

I've taken a k7000 19" board and swapped in a 25" 10 pin neck board - which has worked nicely before with these donor tubes.

In any case, I swapped everything out and I'm getting the attached screen.

Totally possible I've got some wiring wrong during the neck board swap.

Not quite sure what this is, so hoping someone might recognize this and suggest some options to troubleshoot.

Apologies in advance if this is a relatively obvious issue.

thanks
 

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It's nothing I've ever seen. Double check all work. Maybe spliced a yoke connector on wrong, 1 pin off on your cga connector, something on the bottom of the chassis touching the frame, etc. Are you checking yoke hz and vert measurements? If everything is normal with the tube and connections, you probably have a chassis issue. Might try the chassis with a known working tube to narrow it down.
 
Ok, thanks guys. I will go through everything. The chassis, in theory - is recapped, confirmed working, and good to go - so this may very likely be a user error. I will double check everything tonight! Thanks for the quick tips.
 
yeah, I'm going to pull that chassis tonight and I'll post a picture - I have another k7000 on my workbench that I'll compare it to and trace everything out. Something odd going on. I'll post a photo or with any luck, the solution :)
 
More troubleshooting...

Hmm, so I had a quick look at this tonight. Pulled the chassis and had a closer look, looks like everything is ok - although it looked like the yellow/green coming off the yoke to the 4pin connector was not mapped correctly, so I flipped those. No luck.

With this setup, I'm getting the vertical scans lines, as seen below.

The cabinet next to it has a Raiden II board and of course JAMMA, so I pushed it close and used the power and plugged the pcb pins into the chassis, and got the attached picture that shows the Raiden II screen all jacked up - but it has a picture. The picture is flipped and compressed and distorted on the edges. Played around briefly with the v/h-size and position with not much luck.

I clearly need to dig deeper here, but any initial thoughts?

I'm confused, because that Raiden feed should be mapped out fine - what would be causing the flipped screen and compressed/distorted picture?

Any tips are appreciated!

I'm off to do some Googling...

thanks
 

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So in some quick googling I can see that swapping the yellow/green on the yoke connector to the board is going to flip the screen vertically - so that's likely my problem.

So I'm likely getting the correct content on the monitor, but it's vertically compressed and that distortion on the right? You think this may be fixed by messing with the controls in more detail? Is there a way to manipulate the V-Size more effectively, as that didn't seem to adjust when I tried. Thanks
 
Hi Thomas,

The flipped image can be fixed by turning the vertical yoke connect (yellow-green) around. Make sure only to swap the two vertical pins and not swap the vertical with the horizontal.

You can try and adjust the curl at the top (which is the right with the monitor mounted like this) with the 50/60hz pot. Could also be C51.

The vertical size is pretty close, maybe just an adjustment. The horizontal size looks to be too far off for a width coil adjustment (although worth a try), and may need a smaller value cap for C38.

Check the B+ voltage (Meter to 200V DC, add alligator clip to the end of the white resistor on the side of the chassis closest to the tube with the other end to the multimeter red lead, add another clip from the monitor frame to the black lead, ensure they aren't touching anything, then turn on).
 
Nice work, got it going. Like Danv said, flip the green and yellow around on the yoke connector. If it's still in one piece, split the connector in the middle with some wire cutters and then flip the green and yellow part. Unfortunately it's going to be tough to get the pic to fill the screen on this one. You'll need a width cap kit from Security0001 and will have to try swapping different caps from the kit with the C38 on the board. The C38 is the poly cap right above the yoke connector.
 
Ok - will do. I think after i swap the green/yellow back I'm also going to run the board I have in this cab, back into my working JAMMA Raiden II cab to ensure the feed is coming across properly and there's nothing going on with what appears to be a slightly hacked harness and any power issues. If the feed/screen is good, I may swap out the chassis and see if that helps with the picture size. It's a bit frustrating as I just go this k7000 chassis 'new' and was hoping it would be recapped and all good to go.

Do you think these symptoms could be traced to the neck board? What I've done here, is take a 19" k7000 chassis and swapped in a 10-pin 25" k7000 neck board. This has worked before (with the same donor tube) with no problem - but I appreciate all chassis/neck boards aren't the same. I could always try another neck board....

thanks!
 
Ok - will do. I think after i swap the green/yellow back I'm also going to run the board I have in this cab, back into my working JAMMA Raiden II cab to ensure the feed is coming across properly and there's nothing going on with what appears to be a slightly hacked harness and any power issues. If the feed/screen is good, I may swap out the chassis and see if that helps with the picture size. It's a bit frustrating as I just go this k7000 chassis 'new' and was hoping it would be recapped and all good to go.

I don't think there is necessarily a problem (although there may be one) with the chassis.

There is still some debugging to do. It's important to keep in mind that it's not uncommon to need adjustments when you switch a monitor from one game to another.

The curl could be an adjustment and not a monitor issue.

C38 is a polypropylene cap, and wouldn't have been replaced as part of a cap kit or monitor service. The kit KevsArcade mentioned is a special kit of replacement values for C38 to change the width on certain monitors that weren't built with width adjustments.

You did mention that you couldn't adjust the vertical height. This is an issue if the pot doesn't do anything at all. Could be a voltage issue, could be IC2 or IC3.

Do you think these symptoms could be traced to the neck board? What I've done here, is take a 19" k7000 chassis and swapped in a 10-pin 25" k7000 neck board. This has worked before (with the same donor tube) with no problem - but I appreciate all chassis/neck boards aren't the same. I could always try another neck board....

thanks!

The signals for vertical/horizontal drive don't actually go through the neckboard. These signals are generated and shaped on the chassis (horizontal circuit including IC2, HOT, Q10, vertical including IC2, IC3), and fed through the yoke connectors .

Signal from IC1 and the rest of the video processing circuit goes into the neckboard.

This is tough to troubleshoot, because it is *almost* working, and there are a lot of variables.

It may be the case that nothing is wrong, and the issues you see can be adjusted out. However, if the v-size pot actually does nothing, something seems off on the chassis.

It could be that the yoke on the donor tube is not quite right, and one chassis was less sensitive to it being slightly out of spec than the other. This will be really hard to diagnose without trying the chassis on a proper 19k7000 tube/yoke.

Assuming that the yoke is 100 percent correct for the k7000, there could be a voltage issue. I would start by ensuring that B+ is correct. If it is low (due to a resistor drifting too high out of spec) it could cause a small picture.

If B+ is correct (123v), then you can swap in a smaller value C38 for a wider picture (width always refers to the longer dimension of the monitor - so in this case up/down).

Dan
 
What he's referring to as filling the screen is actually the width because he's running it vertical so the adjustment that needs fixed is actually the width. Thomas these tube swaps are some what of a crap shoot sometimes. The yokes on the donor tubes aren't exactly the same as the original K7000 yokes and are usually at the limits for width with some chassis's. The chassis's vary a lot as far as being able to fill the screen on certain tubes, some chassis do it fine while others need to be modded sometimes for width. I think the the width coils them selves are the variable aa they never seem to ohm out the same even being adjusted in the same spots. The width cap kit may get the pic to fit the screen but if it's to far out, changing the value of the width cap to much will start to squish the picture to one side. When this happens I usually just find a different chassis to match the tube better. The neck board isnt going to change anything as far as filling the screen. Have you tried adjusting the width coil? If your not familiar with adjusting the coil, please take note and do not use a metal Allen wrench to adjust it with the chassis powered up, you'll be in for the shock of your life.
 
Ok! So an update. Some good news and some bad.

I traced everything out, and ensured the video feed was wired up correctly. Was still getting gibberish. Testing voltage and tracked it down to a bad power supply. Replaced it, and started get a picture. I had also flipped the wiring so the orientation was correct.

But still, the picture was pretty jacked up. I managed to adjust it to a pretty good spot and all was good! The screen - vertical compression, overall vert size, etc - appeared to be changing over time - Then after powering it up and down, the picture was staying pretty compressed and almost, overlapping.

Well, I then tried to adjust the Horiz size coil and my tool got stuck and when i tried to pull it out, the coil snapped off. Nice.

So now......ugh. I guess I'm going to pull the damn chassis, and try another one. Suggestions on fixing the coil? I was looking at this:

https://www.arcadepartsandrepair.com/store/monitors/wells-gardner-009a2838-002-width-coil/

Thanks for all the help/info guys. Feel like an ass for getting it nearly there and screwed it up!!
 
Ok! So an update. Some good news and some bad.

I traced everything out, and ensured the video feed was wired up correctly. Was still getting gibberish. Testing voltage and tracked it down to a bad power supply. Replaced it, and started get a picture. I had also flipped the wiring so the orientation was correct.

But still, the picture was pretty jacked up. I managed to adjust it to a pretty good spot and all was good! The screen - vertical compression, overall vert size, etc - appeared to be changing over time - Then after powering it up and down, the picture was staying pretty compressed and almost, overlapping.

Well, I then tried to adjust the Horiz size coil and my tool got stuck and when i tried to pull it out, the coil snapped off. Nice.

So now......ugh. I guess I'm going to pull the damn chassis, and try another one. Suggestions on fixing the coil? I was looking at this:

https://www.arcadepartsandrepair.com/store/monitors/wells-gardner-009a2838-002-width-coil/

Thanks for all the help/info guys. Feel like an ass for getting it nearly there and screwed it up!!
That coil is for the 25 inch chassis. There's no replacment for the 19 inch chassis. Does the core in yours still move freely?. I have a few loose ones with no cores inside.
 
Thanks Kev - I don't think so. I'm going to pull it out today and have a look.

Otherwise, since there aren't any replacments, I'm assuming my best bet then would be to get another donor/parts 19" k7000 chassis and resolder?
 
Thanks Kev - I don't think so. I'm going to pull it out today and have a look.

Otherwise, since there aren't any replacments, I'm assuming my best bet then would be to get another donor/parts 19" k7000 chassis and resolder?
See if you can get the screw to come all way out in one piece and let me know. But yeah, need one from a donor chassis or if you have a dead k4900 chassis lying around, the width coil from that will work on the k7000 chassis.
 
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