To answer one of your other questions. The horizontal winding on the connector are the 2 pins spaced further apart.
K7000 Oddity
- Thread starter Infa Red
- Start date
OP
OP
This is what I think too
Ok so with that info, I can tell you the horizontal side is indeed what broke loose. So now, if that did happen to a working monitor would they get the screen seen in my first photo ?
And now I also know and remember, in yoke readings, the larger numbered side is Vertical, lower number reading side is horizontal.
BTW I got busy with other things today, so didn't begin the work. Plus to finalize it, I will need the APAR shipment to come (yoke wire pins) anyway so no rush.
Yes.
If it was more than a single thin line then there could have been a resistive connection to the coil or fault, as someone else mentioned, in the width coil and associated components.
To clarify the K7000 circuit. The width coil circuitry is in parallel with the horizontal coil, not in series. A fault in the width coil components will distort the horizontal drive (change it's resistance/capacitance/inductance/reactance) but not make it an open circuit to create a single vertical line.
This fault, from the symptoms (recapping earlier post), was clearly a working VREG, HOT and EHT and a fault in the horizontal coil and/or connection. The only component in series with the horizontal coil/connection that if open could create a single vertical line is R96.
To add to the troubleshooting clues, it was clearly an open not a short in the width coil or associated components. As a general guide, a short in the horizontal output components would prevent the HOT from being able to drive the EHT and tend to stop the chassis from running and blow the fuse/HOT or create a distorted output, etc. It would present different symptoms.
M K L
Well-known member
This is incorrect. The width coil is in series with the return line of the horizontal yoke and that's because it's meant to add inductance to the horizontal coil. A breakage there will definitely cause the picture to collapse horizontally. R96 on the other hand ties the return line of the horizontal yoke to the B+. What matters is that it's not part of the original K7000 design. It's only present on the 25" version and on the newer 19" chassis (like this one). The early 19" ones don't have it (it's not even in the schematics) which is enough to disprove your claim.
OP
OP
Well let me say this. Both you guys are not only extremely knowledgable but are also helpful. So I want to thank you for helping me in this thread, that hopefully will help others down the road too !
For you guys to even be able to have a debate like this shows you are lightyears ahead of me when it comes to understand electronics and these chassis', etc.. So you both can for sure be happy with yourselves. Even if one of you are incorrect. All that said, as long as all my paths are correct and working along with all my components, and this thing works again, I'll be happy ! lol
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mecha
Well-known member
thank you for clarifying the 19" R96 myth. there's people that think all the 19" models don't have it.
D18 is a part that I remove for cleanup, we had a K7000 or two last year with horizontal collapse and the solder wound up drying up there in the bad way. I reinstall it on the underside to show that I worked on those chassis. those were the most common model to break from the field, so the majority of monitors I fixed were K7000s. one of mine came back with a flyback that failed later I believe, the rest remained in circulation. there's a lot of areas on the K7000 where the solder needs to be cleaned up, for the crowd that think caps and flyback alone are what will get you to the promised land, they're not.
We are here to help @Infa Red troubleshoot and fix his monitor. Happy to take this to a new thread if you want to debate some basic electronics. But to reclarify - R96 is present on this chassis that we are troubleshooting and ties the highest horizontal voltage (B+) to one side of the yolk and the other side is switched to ground by the HOT (the lowest horizontal voltage). These connections alone will drive the horizontal output coil. To change the horizontal width we change (more than just the inductance) via the width circuitry which also goes to HOT (one end via C69/D18) through to the other end (vias L1/R98) which makes it in parallel with the horizontal coil not in series. Not sure how you get that as a series connection.
Yes, a failed horizontal width component being open will effect the width (not the fault here), but will not prevent any width pulse from driving the horizontal coil. Do not confuse this with the possibility of open tracks breaking the HOT - R96 - Hor Coil - B+ connection causing complete horizontal collapse.
If you have any undocumented pcbs or schematics that are different to this, for this chassis, please share them.
OP
OP
Thanks man, appreciate the help too ! But I want to say, by all means you guys can debate about this here, I don't mind, cause I seem to learn something every time you guys post something. LOL I also think it helps others later reading.
Now all that said, I do agree that what would be most pertinent though is to put to the forefront of our discussions *this* particular K7000 (which btw is a CR31 neck type).
Hey btw, @M K L, you know that pic you attached to show testing points ? Well on a side note I noticed that the horizontal position jumper wire for yours was on the "C" pin, most are on "C", the video that @DuffCon linked of Zenomorp chassis fix shows his discovering one that was jumpered to the "R" pin, he specifically said thats not suppose to be there and put it back to the C pin. Well mine was on the "R" pin ! lol Curious exactly why would anyone not want it centered on C ? I moved mine to the C pin, but want to make sure thats ok. And whats the general opinion on this ?
mecha
Well-known member
you'd be surprised. I've had to move jumpers on some vertical games where the high score or life counter on the bottom may be off or something. maybe not a K7000, but G07s you have a degree of H. Pos adjustment via H. Hold. maybe K4900 also. I want to say the K4600 has an H. Pos but the others of that era don't and use the jumper posts instead. I work on too many different things.
The L/C/R jumper pin is in place of a horizontal position pot. It is used to shift the image displayed relative to the sync signal sent.
Not all game video outputs and their sync signal timings are equal, so it is used to try and center the image on the screen (relative to the games sync signal).
OP
OP
Odd though, because this chassis has all the adjustments including a H-Position.
M K L
Well-known member
Here's a pic from my own copy of the K7000 manual:
it's no different from the one that can be found by googling:
https://www.arcade-museum.com/manuals-monitors/Wells Gardner K7000 Manual.pdf
You based yourself on this which is an edit:
https://www.arcade-museum.com/manuals-monitors/Wells Gardner K7000 Schematic.pdf
And if you take a look at the picture I posted above to help infared troubleshoot his issue, you may notice that R96 is not present on that chassis.
Note that the K7201 which is essentially a K7000 with switching power supply doesn't have an equivalent for this resistor.
As for the series/parallel thing I don't know, maybe it's the way the schematics are drawn that is deceiving so I redrew them in an easier, simplified way
(no HV, no H centering, no damping resistors in parallel with the width and linearity coils):
The manual itself says the width coil is a series inductor:
And if we disregard the width coil (which is an obsolete way of adjusting the horizontal size), the linearity coil is also in series with the yoke (as well as C38).
See for instance the schematics of the K7203 which uses the more advanced east west/diode modulator circuit for adjusting the H size.
Literature on this topic also says the same (just a couple of examples):
http://jfsimon.net/public/Power_Semiconductor_Applications_Philips.pdf (p. 324)
https://patentimages.storage.googleapis.com/9d/f0/6d/68faf081c0883a/US4516058.pdf
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That is all great info. However, you seem to miss that the chassis in question does have R96. R96 places a B+ voltage on the positive side of the horizontal coil. In this fault situation R96 will provide current flow to the horizontal coil + side and create some deflection. R96 is not open, Horiz coil has resistance and there is no deflection but a single vertical line. It suggests the B+, HOT and EHT are OK to create the drive the rest of the chassis to display a vertical line. The problem is not a short in the horizontal output or we would have no image (and other problems). This suggests an open somewhere to complete the circuit from HOT to R96 to Connector- to Horizontal Coil to Connector+ to B+. Without that circuit complete there is no horizontal deflection (when the chassis has a working R96), with that circuit there is some current flow causing deflection. With no deflection R96 ok and no broken tracks it suggests a fault in the coil/connection/associated traces. If there was some deflection (via R96) then it is more likely the horizontal linearity/width/position circuitry is at fault.
Your drawing has no R96 and no +ve voltage, only gnd. I have drawn a rough diagram showing R96, B+ and EHT. R96 is in parallel with the horiz. circuitry to the horiz coil. If that circuitry is open, there is still a path through R96 for current to flow for some (not correct) deflection. The circuit is not this simple under normal operation, but we are considering the case of what is causing no horizontal deflection.
The S capacitor across the hot and horizontal linearity and positioning components maybe faulty or open as well but will not create no horizontal (and a single vertical line) when we have series R96 providing some current flow to the horizontal coil.
For a chassis with no R96, it is a totally different situation and any of those horizontal components being open may cause no horizontal deflection because they are in series with the coil and are the only path to B+.
Might all be a moot point anyway, fault premise was no horizontal output. I went back and looked at the image posted and it looks like there is some horizontal deflection, as tiny as it is. I wonder if that image is still correct with the now open (no longer resistive) wire going to one side of the horiz coil.
mecha
Well-known member
another wrinkle: I think maybe the K7193 model has no C37 and that apparently just runs straight to ground. any confirmation on this?
OP
OP
BTW, figured I'd post some pics of the chassis itself and stuff, so it's version can be 100% identified. I heard the K7000 has about 10-15 different versions ? Crazy.
Please ignore the fact my R96 is out, I still haven't repaired those pads yet, but I prepped it for such, cleaned it up and reflowed all problem areas. All ready for my lifted pad repair and I am deciding to replace my R96 too because it was pretty badly discolored and brittle.
Wish I thought to take before pics, because this chassis was filthy. It cleaned up real nice.
Model# says OC WG, so this is a "Over-the-Counter" K7000 ? LOL
Please ignore the fact my R96 is out, I still haven't repaired those pads yet, but I prepped it for such, cleaned it up and reflowed all problem areas. All ready for my lifted pad repair and I am deciding to replace my R96 too because it was pretty badly discolored and brittle.
Wish I thought to take before pics, because this chassis was filthy. It cleaned up real nice.
Model# says OC WG, so this is a "Over-the-Counter" K7000 ? LOL
chilibear13
Well-known member
P447D. One of the best version of the 19" K7000 chassis in my opinion because it has the remote which makes adjusting much easier. Also, components are labeled on the solder side.
OP
OP
Update... after re-molexing the yoke connectors and fixing those lifted pads (and reflowing), etc.. Its working ! All good.
Thank you for your help everyone. This was awesome !
For those interested: And I know it looks rough and I know I went over and beyond, but here are some pics of how I fixed those lifted pads *permanently*.. and my god they are super solid now, no budging at all. I'm happy and it works, thats the main thing.
• 1st I found a high heat PCB epoxy and glued them down, waited for them to cure and cleaned up area a final time.
• I then bent some spare leads to span from the newly scraped "good" parts of the trace to the damaged lifted pads and even bend around to cover the pads perfectly for 100% support around entire pad. I placed them where I wanted them and "tacked" them into temporary place. Notice I left a space between the support leads for the resistor's leads to go in between them after it comes out the hole:
• I then installed the resistor as usual (and bent standoffs in the leads too like the originals) and bent the bottom of the leads over to make it in-between my two support leads, then soldered over it all.
Thank you for your help everyone. This was awesome !
For those interested: And I know it looks rough and I know I went over and beyond, but here are some pics of how I fixed those lifted pads *permanently*.. and my god they are super solid now, no budging at all. I'm happy and it works, thats the main thing.
• 1st I found a high heat PCB epoxy and glued them down, waited for them to cure and cleaned up area a final time.
• I then bent some spare leads to span from the newly scraped "good" parts of the trace to the damaged lifted pads and even bend around to cover the pads perfectly for 100% support around entire pad. I placed them where I wanted them and "tacked" them into temporary place. Notice I left a space between the support leads for the resistor's leads to go in between them after it comes out the hole:
• I then installed the resistor as usual (and bent standoffs in the leads too like the originals) and bent the bottom of the leads over to make it in-between my two support leads, then soldered over it all.
Very nice work! You've come a long way!
If the HOT was bad, there would be no high voltage, so no display at all.
That said, if the yoke circuit is in fact open, the HOT may be stressed because of the impedance mismatch (check if overheating). If the horizontal size and high voltage are ok after the repair, there may be no reason to replace the HOT.
OP
OP
Hey, resurrecting this thread because this is about the same chassis. Thing is running great btw. Got it all tuned in. But I am noticing something I am not sure I noticed before. And that is 2 things, and I want to make sure these are not related to maybe what @Richard48 was talking about and possibly I stressed some other component out that is now not operating to spec ??? IDK man.. so here it is:
• I can not adjust the vertical position down enough. The pot works and I have a lot of "span" that its adjusting up and down (feels like the proper amount). But the images (for TPG) are just so high (to the top) that adjusting it down as far as the pot goes still has it off center by about 1", which looks bad. If I use vertical size to make bigger, then that does work for the bottom but then the top is buried 1" past the top. lol What would cause this ?
• Horizontal size and positioning works fine, BUT unlike before, I now see a whiteish outline of the "edge" of the image area. BUT this disappears if I darken the blacks which I like to do anyway, but still, I have never seen it before like this where I have to adjust it to get rid of something like this.
I can grab pics if requested, but the issues are simply as I described. Not much to see really.
• I can not adjust the vertical position down enough. The pot works and I have a lot of "span" that its adjusting up and down (feels like the proper amount). But the images (for TPG) are just so high (to the top) that adjusting it down as far as the pot goes still has it off center by about 1", which looks bad. If I use vertical size to make bigger, then that does work for the bottom but then the top is buried 1" past the top. lol What would cause this ?
• Horizontal size and positioning works fine, BUT unlike before, I now see a whiteish outline of the "edge" of the image area. BUT this disappears if I darken the blacks which I like to do anyway, but still, I have never seen it before like this where I have to adjust it to get rid of something like this.
I can grab pics if requested, but the issues are simply as I described. Not much to see really.
