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i believe that one divides off main b+ to leak a startup voltage.
just enough to make it run somewhat till +12 comes up from the fly.
maybe the osc ic or whatever is loading it down?
been a while since i worked on one of those.
at least you dont have the sg-613 eater model.
sonys of that era had resistors that would have the coating crumbling off. some were fine and some would be way off.

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I'm new to this site, you're my 1st reply!
If you still need repair help on that old Sony, I know what it is.
The "start-up" circuit on that chassis is complicated; 1 'lytic capacitor!
Your testing the old memory and it ain't what it use to be!
Here goes; the capacitor is a 10uF @ 160V or 250V on the PC Board directly under the CRT. Look at the schematic, it connects from raw B+ thru a resistor to the "+" side of the cap, the "--" side connects to the horiz osc B+ line. I think that was 12 or 18V. Totally simple, only 2 parts! Other makes used over a dozen parts to do the same thing!
It operates like this; when the set is 1st turned on, the raw B+ (150V I think) ramps up and the cap charges thru the resistor to the horiz osc B+ line. Since the cap is like a short circuit when not charged, that raw B+ is dumped thru the current limit resistor to bring up the horiz osc B+ close to normal. The horiz output circuit drives the HOT and the scan derived 18V supply takes over. The start-up cap charges and no current flows from it and the resistor anymore. Walla! Simple and effective!
I bought a KV-1710 from a Sony Dealer I worked at in 1974. We sold and serviced also. That's where I "fell-in-love" with Sony. My little Sister still uses that set in her Daughters' room to play games, etc. The set still looks brand new after 33 yrs. Instant on kept the CRT alive all these years!
Remember, 2 yrs later in '76, no more instant on! That TV won Sony an Emmy, the 1st time a TV got one! That was the most popular set of all times! It was on many commercials, TV episodes, talk shows. etc. That set was the 1st TV to make water look like water!
Anyway I'm rambling! Have fun and Happy Holidays... John

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I've had one of these sets kicking around for about 13 years. It still works, but has bad focus, and a dim picture. Anyone know if I can get an after-market CRT for this model (it's a 17").. and is the flyback, and focus resistor still available for this set??? I'd love to restore it for nostalgic purposes..

Thanks.

The CRT is a 470BEB22, and is a Sony exclusive. I think you can still have it rebuilt by Hawkeye, or VDC. I strongly doubt the flyback and HVR block would still be available, but you can probably find them used. I don't remember ever seeing a bad flyback on one of those, however. The HVR block usually cracks and arcs, but you can often clean it up and seal it with silicone rubber.

Charles

FLyback and focus resistor are still OK. I was just curious if they were still available. Is it possible to breathe a bit of life back into the tube by momentarily zapping the R, G, and B cathodes with some higher voltage??? (isolated from the other circuits of course).. I heard using a megger on 1000 volts could work. Is this true??

I would not zap this tube unless you have access to a decent CRT tester and have confirmed that the tube is bad. Poor focus and a dim picture is indeed a symptom of a weak tube; but, can often be compensated for by adjusting the G2 and focus controls. I've also seen TV's with a good tube that simply needed focus and G2 adjustments after someone had misadjusted these controls.

I've tried all of those adjustments, with no avail. The tube will come a little brighter by increasing the G2 voltage, but with worse focus.. The focus can be corrected slightly, but not perfect.. I'm going to zap the cathodes with quick pulses...

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No focus resistor? Then what is the variable resistor block for above the flyback??

I believe that's an H-Stat control - not a focus control. Please correct me if I'm wrong on this.

Cheers,

That's the HV block, it controls convergence...

Oh that's what that is... I did notice that the convergence does change upon adjusting that pot.. How do I set that up? Do I measure the HV anode and adjust that pot until I get 23.3 KV as per the schematic? Then if the convergence is still out, I can adjust the purity magnetss at the CRT neck?? Is there anyway to adjust the focus, or is it pre-set? Where do I measure the focus voltage? I tried measuring G4, but I get 0 volts. The schematic says 165 Volts...

If it's the same type of control I'm thinking of, it's only used to adjust horizontal convergence. Any other adjustments need to be done on the CRT neck or elsewhere on a small board.

Does anyone have a schematic for a simple CRT rejuvenator ? I'd like to build one to try to restore this 470-BEB22 CRT.... What voltage should I use cathode to grid? Should it be AC or DC???

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So, do I use 200 volts AC between G1, and the cathode? What wattage of a light bulb is optimal?? I think the heater voltage of this CRT is 100 volts. Is that correct??

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Would it be bad to use 200 volts AC across the G1 and cathode for a short duration? I was thinking of picking up a B&K CRT tester rejuvenator. Is the 445 model a good one to do this rejuvenating process?? Which one would you recommend?

Thanks for all of your help.
"Happy Holidays"!!

If you get a B&K, get a 467, 470, 480, or 490. The models below 467 have a very primitive rejuvenate function and you'll likely blow up your CRT. Also, adapters for most tubes are fairly easy to come by for the newer B&K models. I think the 445 dates from the '50's and is for B&W tubes only. The first CRT checker I owned was a B&K 465 from the '60's and I NEVER had any luck rejuvenating a color tube with it. Blew up plenty, though. It worked on some of the B&W tubes. My current model is a B&K 480 from the '90's and I've rejuvenated countless tubes with it. You should be able to pick up one of these fairly cheap on ebay. I'm sure they will get cheaper as time goes on due to the phasing out of CRT's.

What are your thoughts on homemade rejuvenators with the push button, and the light bulb in series?

Is there a way to rejuvenate G2, and G4?????????

How can the focus be corrected on this 470-BEB22 CRT???????

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Is there a particular model of B&K that I should look for? I was told anything older than a 467 isn't safe to rejuvenate tubes due to the primative rejuvenate function.. Is there a focus adjustment on the D, or P boards in a KV-1710??

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The G4 pin on the CRT socket measures 0 volts. It seems to just go to ground through a 470 K ohm resistor. I don't know if someone had been tampering with it before I aquired the set. Do you still have your KV-1710? What does your G4 measure? The schematic says it's supposed to be 165V...

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Andy...

You seem to be quite knowledgable on these Sonys. I also have a KV1710 I picked from the trash with a peculiar problem you may be able to help with.

The set works, and the CRT is good, but it exhibts short vertical at the bottom of the screen, stretched at the top. and the sides are bowed in rather severely. I'm sure it is one or more electrolytic caps, but where to start?

I'd appreciate any help anyone can offer on this problem.

Thanks!

Check The electrolytics in the vertical, and Pin circuits on the P board...

Sorry, my bad. The vertical stuff is on the D board. Pincushion is on the P board. Try adjusting the Vertical linearity as well as Horizontal size. Pots should be along the back of the set.... Also check the 130 volt line to see if it's low..

So anyway, back to my dim picture poor focus issue with my KV-1710 Trinitron.. I disconnected the K and G1 wires from all 3 colour guns on the CRT board. With the power on, I charged a 100uf @ 250v cap to 200 volts. I discharged it across the G1, and K of the guns 3 times on each gun . After this process, the picture was much brighter, and the focus is near perfect... Not sure how long it will last, but it looks great for now!!!