K7000 faint jailbars?

SuperGunGuru

in Memoriam

Donor 2014
Joined
Aug 20, 2005
Messages
5,102
Reaction score
311
Location
Bath, Michigan
Hey all,

I have a couple of K7000 series monitors doing this now so I thought I'd see if anyone knows what might be causing this. There are some faint vertical bars on the left side of the monitor look like jail bars but there barely noticeable. One of the 2 K7000s has been capped very recently and the other is on my to do list. While these aren't so horrible they effect the gameplay, I'd like to see if I can clear them up. Something like this seems like a cap issue so maybe a cap that doesn't normally get changed out with a kit?
 
are they on the immediate left, like 2 bars, and nothing more? cause I got that on my K7000 too. I don't think mine's ever been capped.

I think the width coil on mine needs a little tinkering, when I try to do vertical adjustments it doesn't sit proportionally correct, it's almost like those 2 lines are from foldover, but I don't think that's it.
 
Jailbars are fixed with new caps.

If yours was "capped recently", I'd check that ALL the caps were replaced if you didn't do the cap kit yourself. Some monitor repair guys test the caps on the board and only replace the ones showing to be bad or close to it. This means that an old cap that was good then could be failing now...
 
that's kind of silly, don't you have to pull caps out of circuit to test them? be better off just replacing everything. yeah, that kind of irritates me when people do monitor repairs, like if 2 of 3 color transistors are dead, I'd go and replace all 3. had monitors worked on for that and guess which color dies conveniently when the guarantee runs out? :)

I've read some interesting things about K7000s lately, are there any other components you have to replace in addition to the caps if everything's original?
 
that's kind of silly, don't you have to pull caps out of circuit to test them? be better off just replacing everything. yeah, that kind of irritates me when people do monitor repairs, like if 2 of 3 color transistors are dead, I'd go and replace all 3. had monitors worked on for that and guess which color dies conveniently when the guarantee runs out? :)

With an ESR meter, you can often check a cap while it's still on the board. I agree that it makes no sense to "fix" a chassis and not replace ALL the caps, but I've had some friends show me repair invoices from some repair places that show only a couple caps replaced, along with a flyback, HOT, or something.

Doesn't make sens to me, but I see people here in the repair forums often say, "I have XXX problem and replaced Cxxx and it's fixed." Well, if THAT cap failed, then chances are the others are going to fail soon, so you might as well replace them all (less than $10) while you have it out.

I've read some interesting things about K7000s lately, are there any other components you have to replace in addition to the caps if everything's original?

If everything is working before the rebuild, then the only other part that is sometimes recommended to replace besides the caps would be the original flyback if it shows signs of hairline cracks around the focus or brightness pots. it's not 100% necessary, but it will eventually cause problems, and since replacements are only $19, it might as well be done with the caps...
 
Jailbars are fixed with new caps.

If yours was "capped recently", I'd check that ALL the caps were replaced if you didn't do the cap kit yourself. Some monitor repair guys test the caps on the board and only replace the ones showing to be bad or close to it. This means that an old cap that was good then could be failing now...
The cap kit on the chassis was done by me and IIRC was a Zanen kit. I guess describing them as jail bars can be a bit misleading as they are not very dark at all. They are vertical bars that are ever so slightly darker than the rest of the screen on the left side. Here's a pic from the k7000 in question that I capped. You can see 3 vertical bars on the left side, but like I said they are hard to see and I had to turn out the lights to get them to show up. I can live with them if I have to, but this was the first k7000 I noticed the "problem" with. These are the 25" models if that makes any difference. Sorry the pics blurry but it's my camera and not the flyback.

DSCN0599.jpg
 
Yep, cap them again...

The other K7000 that I haven't touched I was planning to cap anyway since I've had the machine 6 years. This one, the one I showed the pic of, was just capped last August and the game has never seen any kind of heavy use. Are you thinking the kit may have had bad caps or the caps were old enough that they didn't last? I think the cap kit came from an estate auction so I guess it's hard to say how long the original owner had them. I've just never had to cap a monitor a second time before so this would be a first for me and that's what kinda surprises me.
 
Last edited:
I think there's imperfections in the manufacturing process. like brand new caps can fail right away in some rare instances. I had a Polo rebuilt and it had very faint jailbars in the picture, it just happens sometimes.

I had a K7500 I recapped and one of the caps didn't outright explode, but it's got goo shooting out the top. it wasn't put in backwards or anything. I don't run it right now cause I have to fix some traces on the neckboard.
 
yep. I've had 2 motherboards fail from bad caps, and a video card. 2 more of my motherboards I donated to science for my parents use -- both died from bad caps.

these applied to like 2385723582735 types of electronic devices.

good catch mod
 
Thanks for the replies guys. Wow interesting about all the bad caps being sold. I've definitely heard of caps being bad right from the get go, but this would be my first experience with it. Since I need to cap my MK2's K7000 I might as well plan on taking another look at this one that's in my Simpsons. I am tempted to just try replacing C57 to see if that fixes it, but maybe I should just do 'em all again while I'm at it.
 
I have a KI2 with a 25K7000 that is doing the exact same thing. Did you ever solve your's?
 
I have a KI2 with a 25K7000 that is doing the exact same thing. Did you ever solve your's?
I haven't really messed with the issue much at all since posting this. However with a standard K7000 cap kit, there are 3 smaller value caps plus the large filter cap that do not get changed normally. My plan is to try and change them to see what I get. FWIW, I've noticed this issue on a number of monitors in the wild too.
 
I just got my K7000 25" monitor running the other day. It has been sitting in someones crappy shed for about a year or more. After about 1 hour of running one of the caps exploded (nice smoke show) and now I have the exact same jailbars that you have in the picture. It looks like the other caps are about ready to go as well lol.
 
the nice thing about an ESR meter is when you remove a suspected bad capacitor from the chassis or PCB, is you can test it and see what state it is in.

my meter can test in circuit AND will discharge the capacitor before testing it too.
also, i have detected supposed "new" capacitors that tested bad. thank goodness for the ESR meter as i almost installed them. imagine what a headache THAT would have been.

in conclusion, if you dont have an ESR meter, you really dont know what you are removing or installing. in my opinion, well worth the 139 plus shipping to KNOW
 
I've seen some monitors that even after you cap them, there's still faint lines because there's actual burn in on the screen because it was left too long like that.
 
I've seen some monitors that even after you cap them, there's still faint lines because there's actual burn in on the screen because it was left too long like that.
That's a really good point I didn't even consider. I'll have to check the tubes for my K7000's with this issue.
 
Back
Top Bottom