common k7000 issues - common repairs

All of the above-mentioned polys and whatnot have been swapped over to working chassis.
Can you be more specific? I had a similar issue and the culprit was a shorted C38 (poly cap). I would check c36, 38, & 69 (assuming your chassis is a later k7000 without the 4 legged capacitor, otherwise it doesn't have a C69)

 
Can you be more specific? I had a similar issue and the culprit was a shorted C38 (poly cap). I would check c36, 38, & 69 (assuming your chassis is a later k7000 without the 4 legged capacitor, otherwise it doesn't have a C69)


my point was.... All polys were replaced or moved to another chassis. They all tested good.
 
I've got a K7000 skinny neck with a weird issue; its find when it has a video signal but once I turn off the TPG the neck board starts making a sizzling sound. At first I thought it was a bad flyback as it was the original white knob. Swapped in a new one and no change.

I've the focus wire is soldered in properly and I've desoldered the socket to make sure there isn't a solder blob or something causing a short. I've got another skinny neck board I'm going to swap in and see if the problem goes away.
 
I've got a K7000 skinny neck with a weird issue; its find when it has a video signal but once I turn off the TPG the neck board starts making a sizzling sound. At first I thought it was a bad flyback as it was the original white knob. Swapped in a new one and no change.

I've the focus wire is soldered in properly and I've desoldered the socket to make sure there isn't a solder blob or something causing a short. I've got another skinny neck board I'm going to swap in and see if the problem goes away.
are you sure its not coming from inside the neck socket or bad connection to the tube pins?? at this age i am seeing a ton of socket issues from bad sockets.
 
It was for sure the socket, I swapped neck boards and the issue is gone.

Its so weird that it would only do it when the signal was removed.

Video:
 
had another bad K7000. this one produced a loud whine when you turn it on and the HOT would get super hot. D18 is the diode in front of the yoke header, it wound up being that part was bad. we've observed that 19" and 25" models both have different size diodes, and they appear on both P447 and P538 apparently. (I had dumpster dived to find parts chassis)

gamefixer fixed it, but given that nothing else was bad or causing HOTs to die or fuses to blow, I was leaning towards that D18 maybe being the problem. he had another monitor from a T2 that had horizontal collapse, the solder pads I think were demolished. so that's apparently a part to pay attention to.
 
K7000 25". Dead. Found pin 1 solder joint at pin 1 of flyback burnt. Replaced flyback since it was original and machine is on between 10 and 14 hours a day. Monitor would power up but then go into shutdown after a few seconds. Sometimes it would not power up at all and immediately go into shutdown. Tried the usual suspect parts but still no luck. Found cap C37 bad. Read anywhere from open to 100nf and it should be 150nf. Monitor back up and running now. I should have checked that one right away but it doesn't usually fail so I went after everything else first.
 
we need to stop replacing good factory FB's.

That is all I have to add on this matter.

:)
 
Hi all,
I have a Zenith K7000a. It works well but when I first start the machine up cold, it scrolls vertically for a while. After 3-5 minutes it stops scrolling and Is fine. I can then restart the machine and it remains fine.

Any tips on fixing this? It's not a huuuge deal just slightly annoying.
 
Probably cold joints, check the header pins, especially pin 10 which is sync.
 
Fun quick story: Per the gospel of @mecha


And mentioned in this thread. A very common posting around here is the "I capped the monitor and now it's broke". A lot of the time, newbies (including myself) stumble through a cap kit and ignore the common problem areas.

I got a chassis a while back that had been capped with a flyback, so in my mind everything was fine (visually on top) and the picture was great. I started noticing the monitor had a lot of bloom issues (when a picture goes from dark to light, it will noticeably be slow to paint the screen). I know this is usually related to a bad Voltage regulator (IC4) or filter cap (less common). I checked the B+ and it was low, something like 110v.

So I took a look and guess what:
E613CEF1-E409-4517-9FF2-E36DB5EE003E.jpeg

The VR had been replaced at some time but was never actually soldered in place! Also the regular problem resistor pads at R101, R89, R96, R103 were completely lifted. I have no idea how this chassis was actually working. I spend a long time repairing the traces and giving the whole chassis a proper re-work. It's rock solid now. No blooming and beautiful!
 
Fun quick story: Per the gospel of @mecha


And mentioned in this thread. A very common posting around here is the "I capped the monitor and now it's broke". A lot of the time, newbies (including myself) stumble through a cap kit and ignore the common problem areas.

I got a chassis a while back that had been capped with a flyback, so in my mind everything was fine (visually on top) and the picture was great. I started noticing the monitor had a lot of bloom issues (when a picture goes from dark to light, it will noticeably be slow to paint the screen). I know this is usually related to a bad Voltage regulator (IC4) or filter cap (less common). I checked the B+ and it was low, something like 110v.

So I took a look and guess what:
View attachment 637166

The VR had been replaced at some time but was never actually soldered in place! Also the regular problem resistor pads at R101, R89, R96, R103 were completely lifted. I have no idea how this chassis was actually working. I spend a long time repairing the traces and giving the whole chassis a proper re-work. It's rock solid now. No blooming and beautiful!
Yikes.
 
Probably cold joints, check the header pins, especially pin 10 which is sync.
Thanks! I'm going to pull the chassis out tomorrow night and get to work.
I was messing around with it yesterday and tried fiddling with the h-hold knob. I realized turning it changes nothing. I turned it all the way left and all the way right and it didn't change anything with the picture. Does this mean the pot is bad?
Anyone know where I could find replacement pots if that is the case?

Also -- side note. The scrolling behavior is specifically when using a mistercade. When I try these other boards I have (Tekken 2, soul edge, point blank 2) I don't get the scrolling, but instead some curling and like.. distortion? And it doesn't go away after warming up.
See here: https://photos.app.goo.gl/LH9xf7jmoanHnjEZ6

Just wondering why the mistercade doesn't have those issues and is eventually fine but scrolls until "warm".

Thanks for any help! Kind of intimidated discharging the monitor and everything but I'm pretty decent at soldering.
 
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Thanks! I'm going to pull the chassis out tomorrow night and get to work.
I was messing around with it yesterday and tried fiddling with the h-hold knob. I realized turning it changes nothing. I turned it all the way left and all the way right and it didn't change anything with the picture. Does this mean the pot is bad?
Anyone know where I could find replacement pots if that is the case?

Also -- side note. The scrolling behavior is specifically when using a mistercade. When I try these other boards I have (Tekken 2, soul edge, point blank 2) I don't get the scrolling, but instead some curling and like.. distortion? And it doesn't go away after warming up.
See here: https://photos.app.goo.gl/LH9xf7jmoanHnjEZ6

Just wondering why the mistercade doesn't have those issues and is eventually fine but scrolls until "warm".

Thanks for any help! Kind of intimidated discharging the monitor and everything but I'm pretty decent at soldering.
@security0001 I guess doesn't sell a pot kit for the deflection board, only remote board, but I'm sure he can unearth a H. Hold replacement. but you probably don't need it, I would think if it were bad you would just have a scrambled mess on the screen. LOL it is strange you went to both extremes and couldn't get the sync to break. if you have a vertical rolling picture, that's V. Hold. if you haven't tried that yet.
 
@security0001 I guess doesn't sell a pot kit for the deflection board, only remote board, but I'm sure he can unearth a H. Hold replacement. but you probably don't need it, I would think if it were bad you would just have a scrambled mess on the screen. LOL it is strange you went to both extremes and couldn't get the sync to break. if you have a vertical rolling picture, that's V. Hold. if you haven't tried that yet.
if your talking about VR2 then yes its here.

 
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