What causes a shaky image on a k7000?

Broodwich

Well-known member

Donor 6 years: 2012-2013, 2015, 2020, 2023-2024
Joined
Feb 20, 2011
Messages
9,846
Reaction score
420
Location
Albany, New York
My Spider-Man Cabs k7000 has been acting up a lot lately (it's been getting a lot more use). I noticed the other day that with my cps2 games the screen would shake a little and the screen would flash occasionally (screen flash would also happen with KI1), is this a simple adjustment issue or do i need to start thinking about having the monitor chassis capped ect.?

Edit/Update: I took a look at the caps and everything looks in order, nothing leaking, no jiffy pop tops. I did see some dust so i hit the monitor chassis with a can of air.The flash is only noticeable on Spinals rooftop in KI, it's much more prominent on Marvel Vs. Capcom where it will happen super often during game play but not on the character select screen (but definitely when the VS screen pops up). Flickering is set to OFF on MvC
 
Last edited:
cap that thing.

sounds like a cap kit is in order. if it has not had one.

i have k7000's in my ki1, ki2 and my mortal kombat's and after a cap kit and a fly it stopped all the flashing.

so i would start there.

Peace
Buffett
 
it sounds more like you're talking about blooming. in that case, you replace the large filter cap to correct that. happens on my SFA3, it's only noticeable when you do Akuma's Raging Demon though. :)

cap kits work wonders on those K7000s regardless though, and they're relatively easy to do if you make a cap map or download one before you do the job, cause a lot of cap labels are covered in epoxy and goo.
 
I googled "blooming" but i couldn't find much info/images showing what exactly it does, seems like it's more along the lines of the picture starting small and growing large (i'm probably wrong on this lol).

I'll try and take a vid tomorrow showing the flashing (the shaking is a little harder to point out) but i'll try and get that too.
 
I took a look at the caps and everything looks in order, nothing leaking, no jiffy pop tops.

I have done more than a few cap kits and rarely do I see visible issues with caps. Just did one on Saturday for a k7901 chassis that had no picture at all before and a perfect bright image after. None of those caps had anything visibly bad.

If you haven't done a cap kit, definitely do it anyway. The picture will benefit and the monitor will be better off. I will say my first thought was the flyback when you mentioned flickering. Anyway, just my 2 cents, I'm learning too and definitely no expert. :D
 
It's pretty rare for caps to actually bulge up on arcade monitors, unless something really horrible happened to it. Usually they just start getting crappy electrically, or leaking slightly out the bottom. Your "flashing" - does it seem like the whole picture is changing size when the content on the screen changes rapidly? Or are you getting random white flashes? Or, are the colors smearing to the sides when it gets bright?

Another thing - does your flyback have white knobs? If so, I'd suggest changing it while you're in there.

I've done lots and lots of K7000's - I've not had to replace a filter cap in one yet, but the rest of the caps are going to be suspect if you've never changed them. But, don't forget to check the neckboard, some versions of the K7000 have a 4.7uf cap there, it needs to be changed as well.

Let me know if you need any help. You can always call.

-Ian
 
No white knobs! :D This machine use to have a white knob flyback but a buddy of mine swapped out that chassis for one without around 6 years ago (as the flyback housing was cracked and it was arcing to the frame). This buddy worked for the local Namco Arcade which has since closed.

The Picture definitely isn't changing in size just shaking (and not by much) and doing the flashing thing. i'll try and get a vid of it up.


Update:

The shaky image seems to go away after it warms up a bit, so i guess the real issue is the flashing of the screen. Here's a vid showing what it does, tho i don't think that my crappy kodak z740 camera can pick it up that well.



flash happens at these time stamps: 05, :12, :23, :40
 
Last edited:
Bumping this because sometimes even i wonder if i know what i'm talking about :D
 
Bumping this because sometimes even i wonder if i know what i'm talking about :D

Should replace the caps and reflow the solder connections
Make sure theres no cracks in the remote board pots.
Or I would suspect C204 on the neck board and C57 on the main board first.
 
Try the "shake" method -- i.e. leave your camera filiming the game in demo mode and move your RGBGsync cables around a little to see if the picture changes. Also, give a little tap to the neck board on each side as well to see if you see a correspondance between the shaking / thumping and the white flashes on screen.

Also, if you have a pattern generator, hook it up to your display to see if you get any flashing. Lastly, if you game has a test mode, then go into the video tests and let one of the color tests stay on screen. Then act like your playing the game to see if you are getting the same flashes.
 
It's pretty rare for caps to actually bulge up on arcade monitors, unless something really horrible happened to it. Usually they just start getting crappy electrically, or leaking slightly out the bottom. Your "flashing" - does it seem like the whole picture is changing size when the content on the screen changes rapidly? Or are you getting random white flashes? Or, are the colors smearing to the sides when it gets bright?

Another thing - does your flyback have white knobs? If so, I'd suggest changing it while you're in there.

I've done lots and lots of K7000's - I've not had to replace a filter cap in one yet, but the rest of the caps are going to be suspect if you've never changed them. But, don't forget to check the neckboard, some versions of the K7000 have a 4.7uf cap there, it needs to be changed as well.

Let me know if you need any help. You can always call.

-Ian

***THREAD DERAILING POST*** (maybe)

K7000 in my Street Fighter cab has blooming on bright/white screens. I had to change out everything on that one due to the damage the flyback did (which I'm sure I've shared with you too lol) ... it's also developed some other weird thing since Broodwich said something about his where it'll get black lines that flicker in and out at times. I tried tapping the frame and wiggling the video header and it didn't do it then. I highly doubt it's cold solder anywhere, cause I did EVERY major component on it, even C38.

that said, am I looking at needing to change the filter cap on it after all? lol
 
you know, i always forget to check the neck board for bad caps, i'll check today (visually, which will prolly show/tell me nothing).

The only pattern gen i have is the grid test screen. I was having problems with one of the RGBsync wires a couple weeks ago but that seems to have gone away (red was being flaky).

I'm putting my chips on it needing a full service (cap kit, flyback ect...). Looks like i'll have to pull it soon and go from there >.<
 
you know, i always forget to check the neck board for bad caps, i'll check today (visually, which will prolly show/tell me nothing).

The only pattern gen i have is the grid test screen. I was having problems with one of the RGBsync wires a couple weeks ago but that seems to have gone away (red was being flaky).

I'm putting my chips on it needing a full service (cap kit, flyback ect...). Looks like i'll have to pull it soon and go from there >.<

yeah, I rebuilt a K7000 a couple weeks ago. only thing I didn't do yet was the C36 cap mod, since they don't make the 4 legged type anymore lol. I haven't even tested it yet, but it came out of the T2 I used to have (I pulled the tube and dropped another K7000 on it, which went into my MK2) and it didn't do anything.

do all caps, flyback, I wound up changing the HOT and the VR too, C36, C38 only if you have problems with width. if yours is already working and you have a black knob flyback that doesn't look like it came from 1492, you should just be fine with caps. I changed everything assuming the flyback took a shit, and because I wanted a full rebuild lol.

make note of the numbers on the voltage regulator if you wanna go all out, there's a STR3130 and a STR30130 and they're different. you will also want some isopropyl rubbing alcohol for cleaning the HOT and VR insulators and new thermal paste to stick on both sides (I did anyway) I personally use Arctic Silver Ceramique, and you can get that at Radio Shack. DO NOT lose the insulators if you change those out.

oh... and make sure you have some kind of desoldering device heh.
 
The only pattern gen i have is the grid test screen. I was having problems with one of the RGBsync wires a couple weeks ago but that seems to have gone away (red was being flaky).

If you have any junk Midway boards laying around, they have good monitor patterns in their test menus. Solid color screens, crosshatch, and gradient color bars. I'm using a Mortal Kombat board myself, but any of the other Midway games from that era have the same test patterns. (Smash TV, NBA Jam, etc). You don't need the sound board for testing monitors.

-Ian
 
yup i normally use the test screens on whichever board is plugged in at the time, and i agree the midway test screens are #Win.

And what do you mean no sound board needed for test patters, i wanna hear those grids MOVE! lol

I don't have a desoldering gun/station just my trusty bob roberts solder sucker. And i'm a huge fan of Arctic Silver 5 (i keep stock in it as i do a ton of PC's), best stuff for the money imo (tho i haven't really messed with the ceramique).
 
yup i normally use the test screens on whichever board is plugged in at the time, and i agree the midway test screens are #Win.

And what do you mean no sound board needed for test patters, i wanna hear those grids MOVE! lol

I don't have a desoldering gun/station just my trusty bob roberts solder sucker. And i'm a huge fan of Arctic Silver 5 (i keep stock in it as i do a ton of PC's), best stuff for the money imo (tho i haven't really messed with the ceramique).

I use the Ceramique because the silver breaks down over time. the white stuff, even the generic radio shack stuff, will last a long time.

and the reason I built out my supergun was for plugging some of my shit ass MK boards in for the patterns for calibrating monitors lol
 
good to know about the ceramique and silver. i'm sure both are kinda overkill tho for most arcade applications but if it's available why not :D
 
yeah, the ceramique I'd say is pretty premium quality shit for this application, but if you care about it enough, you'll give it the proper attention it deserves right?
 
seems the ceramique is the only one thats 100% non thermal conductive too.
 
Back
Top Bottom