Low B+ on K6100

jehuie

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I've got an intermittent flicker on my Tempest monitor. During testing I noticed that the B+ is around 157 rather than 180 volts. Is this a likely cause for this kind of problem? And in any case, what's the best way to proceed to find the cause for the low voltage?

This question was listed in another thread but it was buried so I thought I'd ask it here. Thank you all!
 
It depends on what you call a "flicker". 6100's tend to squiggle a little bit, especially if you don't have the mesh cage on the HV box.

As for your low B+, you may want to go over it again for cold solder. For instance, the black PTC behind P100 on the deflection board often has cold solder. And if you have a P314 deflection board with an Input protection board, it often has cold solder on the legs of that board...
 
Thank you...I'll check for those things. By flicker, I mean that it actually flickers out and back in...like the image disappears or nearly disappears just for a fraction of a second. Also, I've noticed once in a while that it went out of focus on me for a few seconds and then snapped back into focus again. It's done that a couple times now.
 
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the wires on the back of the focus and brightness pots just plug in - no solder. Sometimes the come out a little when doing a rebuild. Check that...
 
the wires on the back of the focus and brightness pots just plug in - no solder. Sometimes the come out a little when doing a rebuild. Check that...

also check where they hook into the plastic connectors, where coming from the hv and one from the neck board as min broke and i had to fix it
 
Thanks guys. I think you are on the right track. It looks to me like everything is well connected. However, when I go to adjust the focus, it feels like it's only loosely controlling the actual focus. When I turn the focus pot, it's not a smooth transition. This is hard to explain. It just feels sloppy though. Like I can turn it for a bit and nothing happens and then suddenly it changes a lot.

So perhaps the pot is shot. It looks to be molded into the plastic though. Can you replace just the focus pot or does the whole piece have to be replaced? Actually, it's attached to the flyback right? I hope I don't have to replace that whole deal....I don't think they are even available now are they?
 
Thanks guys. I think you are on the right track. It looks to me like everything is well connected. However, when I go to adjust the focus, it feels like it's only loosely controlling the actual focus. When I turn the focus pot, it's not a smooth transition. This is hard to explain. It just feels sloppy though. Like I can turn it for a bit and nothing happens and then suddenly it changes a lot.

So perhaps the pot is shot. It looks to be molded into the plastic though. Can you replace just the focus pot or does the whole piece have to be replaced? Actually, it's attached to the flyback right? I hope I don't have to replace that whole deal....I don't think they are even available now are they?

you can find one here http://www.arcadecup.com/
 
goodluck and let us know

EDIT also check the wires at the connector circled in this picture, you may have to splice the wires or get a new connector or something
 

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Well, I replaced the flyback and it still does the same thing. Jumps out of focus suddenly. I was hoping that replacing the focus pot would fix it but it clearly wasn't the problem So I guess I'll pull the thing apart and go back over all the stuff you guys pointed out earlier...again. :) It's a fun little mystery I guess.

And I suppose that means that I have a spare flyback for a k6100 if anyone needs one. It's used but should be good.
 
replace your neckboard socket..
they are known to have focus problems I replaced about 7 that had a bad focus pin.
could also be the cause for a possible loss of g2..
 
replace your neckboard socket..
they are known to have focus problems I replaced about 7 that had a bad focus pin.
could also be the cause for a possible loss of g2..

Interesting. Do you sell those also? I'm very pleased with your flyback by the way. Had a little trouble getting the pins to align at first but it went in eventually. Oh, and one question....when I went to screw down the controls for focus and brightness, the other end of the thing raised up. I tried adjusting it but every time I tightened the screws down it would spring back up in the air again on the other end. Have you seen that before? I just fashioned a little clamp for the other end and all is fine. Not sure if that was a unique problem to me or not.
 
Yup those new flyback focus mounts dont like to stay put.. I just use wire ties works wonders. :)

I could get you a pull for $12.00 shipped..
pp [email protected] if you want the socket.
 
Chads probably right but have you considered metering the HV board voltages to see if it's possibly having fluctuation on the low side when it gets fuzzy?
 
Chads probably right but have you considered metering the HV board voltages to see if it's possibly having fluctuation on the low side when it gets fuzzy?

Hmmm. That's a thought. I'm not sure if my digital meter would have a quick enough response to catch the quick fluctuation or not but it might be worth a try. It just flickers really fast and then the focus changes. I've got it all torn apart again right now but I'll try that if it's still doing it after I get it all back together.
 
Well crap. I've done nearly everything you guys suggested here. Reflowed solder on everything under the sun. Checked all those wires and connectors. I almost came back and said it was working....played it for maybe 15 minutes with no problems....then it jumped again. I had the meter hooked up but couldn't see any real change in that voltage.

Still not even sure if the low (157 rather than 180) voltage is related to this problem or not. The could be totally separate issues or they could be one and the same.

Is there a way to check that neckboard socket to see if it's ok before ordering another part that I may not need?

Thanks guys!
 
Ya wiggle it to see if you can produce the intermittency or not...
And, lean something against or it do a rubber band trick to put pressure on it to see if that prevents the intermittency.
Good luck.
 
Still not even sure if the low (157 rather than 180) voltage is related to this problem or not.

Ummmm that's not good dude. That voltage is WAY too low. You're monitor is shitting itself trying to keep up.
THAT'S where you need to focus your attention to.
Usually low voltage like that - swap out your zener diodes. I also had one HV that I darn near replaced everything and the voltage was low. Eventually found the 555 cmos chip was screwed.
 
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