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  #31  
Old 10-14-2017, 08:02 PM
zeno zeno is offline
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Very nice work Mr. Freon !
BTW I sure miss R12 & R22 !

Tom C. gives good advice. I will look for the Sams & PM you.
The bend going through the picture is classic bad filter caps.
IIRC these use a voltage doubler & one bar is 60 cycle getting
on the sets B+ line. When it hits the top the set tries to sync
the vert ( also 60 C ) & makes it roll. Sets with full wave bridges
will show 2 bars. Bottom line is it will probably come back.

Lastly keep in mind these sets are NOT bright or super sharp
like newer ones. After its properly set up it should look very
good.

73 Zeno
LFOD !
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  #32  
Old 10-15-2017, 05:00 PM
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Freon Freon is offline
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Well I spent all of last night messing with the back pots and I've gotten it as best as I possibly can with what I currently know. See here. Greyscale is good, but overall picture is still washed out and everything has this weird bright halo to it. Sharpness still varies quite a bit, I caught these pics when it was on the very low end. Typically it looks good on power on and gets gradually worse. I've found the only way to get a correct contrast image without overbright is to turn every color G2 to its minimum, and user brightness to maximum. But this produces a lot of black crush.

I still believe there is a master G2 somewhere, and it is WAY too high. But I can't find it anywhere, or the focus terminal for that matter, and hoping at this point that someone else will know where they are..
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  #33  
Old 10-15-2017, 06:44 PM
Bill R Bill R is offline
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Master G2 is often labeled CRT Bias. Run it as low as possible.
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  #34  
Old 10-15-2017, 06:46 PM
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Electronic M Electronic M is offline
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I saw your PM and am working on the schematic. My box is close to PM capacity and I'd prefer to limit it's use to transactions and confidential info. All you gotta do is ask here and I'll post better pics as soon as I can. [edit: here are the pics]

In the top right hand corner of my third pic you can see the complete G2/focus control circuit. Each color gun has it's own G2 pot the pots connect to the 270V B+ rail and the 720V B+ Boost rail there is no master G2 or anything that would create that effect electrically. The focus is controlled by connecting the black wire from pin 9 of the CRT to one of three points 720V B+ Boost (through R206 for safety), 270V B+ (through R226 also for safety), or directly to chassis ground...You try each connection for focus and leave it set to the one that looks best....You could add a 5M ohm pot between any of the two taps and connect the focus grid of the CRT to the pot's wiper.

I have over 20 deltagun color TVs and have had many more. I can tell you that almost* no deltagun CRT based set ever had a master G2, and yours definitely does not. Master G2 controls did not become standard until inline-gun tubes took over.

* I have a late 60's Admiral that has only a single (master) G2 control...The rest of it's grey scale control system is completely idiotic and ridiculously hard to set up correctly.
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Last edited by Electronic M; 10-15-2017 at 07:06 PM.
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  #35  
Old 10-15-2017, 06:47 PM
Bill R Bill R is offline
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Have you tested the CRT? The blue looks like possible low emission. Focus is deffinately off. You will need to get a HV probe to measure high voltage at the CRT. It looks low. That could cause the focus problem as well.
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  #36  
Old 10-15-2017, 07:12 PM
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Electronic M Electronic M is offline
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Quote:
Originally Posted by Bill R View Post
Have you tested the CRT? The blue looks like possible low emission. Focus is deffinately off. You will need to get a HV probe to measure high voltage at the CRT. It looks low. That could cause the focus problem as well.
Yes, If the HV is low it can ruin the focus. If the CRT has good enough emission HV can be VERY low and reasonable normal brightness can still be achieved at the cost of terrible focus.
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  #37  
Old 10-17-2017, 11:50 AM
zeno zeno is offline
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There is a brightness range on rear near the power
transformer. When you are done you should be able to
turn the brite, contrast & color level all the way DOWN
and not & not get a pix. Also should have no thin white lines.
Recommend you also test the HV.

73 Zeno
LFOD !
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  #38  
Old 10-21-2017, 04:32 PM
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Freon Freon is offline
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Belated announcement time: As I don't have the tools or experience to move on with restoring this set, and I am ridiculously short on space as mentioned before, I have decided to sell this set once again. It was a tough choice to make, in part because I didn't want to disappoint y'all by giving up right after raising this set from the dead. But, I've got a Sylvania Superset doing me service with no sign of failing anytime soon, and I have no need for another CRT right now.

So, new sale thread here.
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