Another K4600 focus problem...

modessitt

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Focus is off, and it won't get better or worse with adjustment.

1) swapped out the focus pot - nothing.

2) swapped out the flyback - nothing.

3) swapped the tube - nothing.

4) Reflowed the neck socket - nothing.

5) Checked continuity from the focus pin socket to the flyback is good.

What next? I'm thinking about swapping the neckboard to see what happens....
 
I too have a burn free 4600 with the same focus problem and I picked up a 4600 complete with 3 extra chassis to find the stupid ass problem

Andrew
 
Well, I pulled a neckboard out of a parts box and was about to change it out, when I thought, "Why not just swap that capacitor to see if it fixes it?"

So I did.

Now I have a perfectly-focused, crisp picture. Apparently the 100pf 12kv capacitor was bad. I'll bet this is the issue with the other one I have that ALMOST focuses perfectly before the focus knob hits it's max turn.

Unfortunately, it appears that Mouser has a 14-week lead time on them:

http://www.mouser.com/ProductDetail...=sGAEpiMZZMt1mVBmZSXTPEZzxJbZaR64wcmqiCawGX8=
 
Awesome will change mine out too and see

Andrew

Well, I pulled a neckboard out of a parts box and was about to change it out, when I thought, "Why not just swap that capacitor to see if it fixes it?"

So I did.

Now I have a perfectly-focused, crisp picture. Apparently the 100pf 12kv capacitor was bad. I'll bet this is the issue with the other one I have that ALMOST focuses perfectly before the focus knob hits it's max turn.

Unfortunately, it appears that Mouser has a 14-week lead time on them:

http://www.mouser.com/ProductDetail...=sGAEpiMZZMt1mVBmZSXTPEZzxJbZaR64wcmqiCawGX8=
 
I might have one of these. If I dont have a new one I do have a parts chassis I could pull it from.


Well, I pulled a neckboard out of a parts box and was about to change it out, when I thought, "Why not just swap that capacitor to see if it fixes it?"

So I did.

Now I have a perfectly-focused, crisp picture. Apparently the 100pf 12kv capacitor was bad. I'll bet this is the issue with the other one I have that ALMOST focuses perfectly before the focus knob hits it's max turn.

Unfortunately, it appears that Mouser has a 14-week lead time on them:

http://www.mouser.com/ProductDetail...=sGAEpiMZZMt1mVBmZSXTPEZzxJbZaR64wcmqiCawGX8=
 
I might have one of these. If I dont have a new one I do have a parts chassis I could pull it from.

Well, I pulled mine from a parts chassis, but I have a couple that could use one. I'm going to look around for other suppliers, but I might just put some on a Mouser order and wait until they come in...
 
BTW - why is it wrapped it what looks like electrical tape? I don't see what it could short to...
 
I'm kindof a new at this. My 4600 also has a focus problem. Which cap it this? Does anyone have a pic of their board that would help me? And do the daughter cards need to come out too? If so, I guess I'll go ahead & replace everything ($ providing). Thank you.
 
I'll try to get a pic for you later if nobody else does. It's usually caused by the cap or a bad focus pot on the flyback....or a bad tube...
 
I'm hoping for the cap. The focus will change when adjusted. It goes from almost good to "what does it say?" If I read correctly, the cap is on the neckboard?
 
Yes. It goes from the focus socket wire to ground. It's usually wrapped in electrical tape...
 
Found it! I have yet to remove it though. I'll investigate more later. I'm not used to the cold yet.
 
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Yes. Thanks you Modessitt for sharing with us. Good to know. I still havn't messed with mine. Now that it's warm out, I hope to be getting to it soon.
 
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And this is why folks need to post their solutions, so that future techs will have a possible fix.

I hate searching a problem, finding the exact same symptoms, and it either ends with "I'll try that" or "I bought another that works so I'll come back to this sometime..." :rolleyes::mad:
 
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