k7000 gets darker suddenly after being on for 30min.

mrbill2084

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k7000 gets darker suddenly after being on for 30min.

Guys asked me to fix his 3 in 1 game and it has a k7000a in it. It was getting dark, but I think also drifting focus( recapped it and no change).

So I put a k7000 chassis I had around in it and that chassis was getting dim after time (I did not notice if it was gradual or sudden).

So I stuck a 2rd k7000 chassis in it. This one just would make a dull pic. Turn up bright/contrast and colors and it would bleed. I did not leave it on long enough to see if it would go dim. I put that chassis in another k7000 cab. It has a decent pic in the tube.

So I grabbed a 3rd k7000 chassis. That one would adjust to a good pic. This time I was playing it(dig dug on a 60 in 1 I put in) and right after I finshed a game, when it switched to select screen it was dim. Tried it again the next day and it was dim after about 30 min.

Any ideas? Tube, yoke, PS, or isolation transformer? I will meter the yoke on friday. I hit the tube with the rejuvinator and it said it was good.
 
I don't think the yoke would do that, no. (this just takes a little dot in the middle and stretches it horizontally and vertically)
power supply is completely unrelated to the monitor's operation. and the iso either works or it doesn't, right?

tube... best possibility. though a little backwards! sounds like the heater's jacked up. not too familiar with that though. I would say you should throw the tube on a rejuvenator for testing.. weak guns would cause the smearing if you have to turn the brightness/contrast up high to see a picture.

if you hadn't tried a half dozen chassis, I would've said it was the flyback on the K7000A, but if you have the odds of having 4 bad flybacks in a row I would strongly encourage you go play the lottery immediately.
 
if it is the heaters you can turn the heater voltage up a little bit more to see if there is any crap on them.

just dont take it to high or you will burn them up or destroy them.

don't rejuve it wile you have the heater voltage turned up. just let it set and burn for a moment.
then let it cool down and try it again with the game hooked up.

also make sure the tube is face down on a blanket or something so the crap falls away from them.

tap on the neck a little with a rubber tool of some vintage to help dislodge any debris that may be in there.

just be easy when tapping you don't want to neck it.

Peace
Buffett
 
if it is the heaters you can turn the heater voltage up a little bit more to see if there is any crap on them.

just dont take it to high or you will burn them up or destroy them.

don't rejuve it wile you have the heater voltage turned up. just let it set and burn for a moment.
then let it cool down and try it again with the game hooked up.

also make sure the tube is face down on a blanket or something so the crap falls away from them.

tap on the neck a little with a rubber tool of some vintage to help dislodge any debris that may be in there.

just be easy when tapping you don't want to neck it.

Peace
Buffett

good tips! I don't think I ever have seen anything say rejuv with tube face down, but it makes sense.

I did hit the tube with the rejuvinator again. It said all was good. Interesting twist. I rejuved green, then red. After I did red green dropped. I hit shorts and no change. rejuved green again. Now green was good and red dropped a little bit.

After the rejuv, I left the game on for 4 hours and no problems with the screen getting dark.
 
cool glad to hear it worked.

cool glad to hear it worked.

yes i use those tricks when i have a tube in need.

some times you need to give it a push even if the rejuvinator says it's good.
there can be some intermittent crud on the guns and heater.
that's why i always do it face down.

fingers crossed for it being fixed.

Peace
Buffett
 
cool glad to hear it worked.

yes i use those tricks when i have a tube in need.

some times you need to give it a push even if the rejuvinator says it's good.
there can be some intermittent crud on the guns and heater.
that's why i always do it face down.

fingers crossed for it being fixed.

Peace
Buffett


I will burn it in for another 6-8 hours and see what happens. If the issue returns I will try to work it as you suggested.
 
Maybe, but it should fall away to the bottom edge when the tube is back to normal position. Better that than having bits in the neck where they cause a major problem. This is also why cocktail monitors have more problems, the crud falls into the tube neck. And a good reason why games should not be transported lying on their back. Road vibration dislodges crap that then falls into the neck of the tube.
 
Could this not result in the rubbish ending up on the face of the screen?

i suppose it could but i have never seen it happen.

Maybe, but it should fall away to the bottom edge when the tube is back to normal position. Better that than having bits in the neck where they cause a major problem. This is also why cocktail monitors have more problems, the crud falls into the tube neck. And a good reason why games should not be transported lying on their back. Road vibration dislodges crap that then falls into the neck of the tube.

yup those are both good reasons for some tube failures.

i don't like to transport them on their backs but i don't have much choice most of the time.

Peace
Buffett
 
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