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  #1  
Old 07-07-2014, 06:35 AM
jstout66 jstout66 is offline
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Charles? Sony KV-1722

Tech Question:
Here's an odd one. ( or maybe not odd to those in the know.
On a 1975 Sony KV-1722 I've got high-voltage and sound and NO picture.
The filament is not lighting on the CRT. I'm leaning towards something in the instant-on circuit? Would be a shame to junk this one out, as the picture tube is actually good. * here's a pix when it was actually working.
Does anybody have the SAMS?
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  #2  
Old 07-07-2014, 11:03 AM
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zeno zeno is offline
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First off there are 2 major versions of this set & a lot of
minor changes. If you slip in this set it can be a major disaster.

T901 is fil xformer. 6.3 VAC goes right to pins 1 & 8 of CRT.
Instant on is an 820 ohm 5 W in series with T901 primary.
Part of the on/off sw shorts the resistor out when on
to give full AC to primary.

T901 is behind & to left of the small power supply PCB. If
you tilt it back you will see it.
Good luck

73 Zeno
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  #3  
Old 07-07-2014, 07:08 PM
walterbeers walterbeers is offline
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Sony kv1722

Well, I'm also helping out jstout with this Sony. Well I think I had a disaster. I found the transformer to be open on the primary side. So I decided to remove the transformer, and see if I could find a replacement. Then I put the circuit boards back in place, and darned, SMOKE!. I must have shorted something on the power supply board. The 2 SG613 are not shorted, but I burnt out R608. It has been replaced before, and the color code is burnt too bad to read. It seem to connect to SG609, which is a SCR type thing. Like was said one mishap and puff it's gone. Well any info, or otherwise might have to junk set.
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Old 07-08-2014, 06:57 PM
walterbeers walterbeers is offline
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Bad news, after rechecking the SG613s, yes, both the horizonal output and regulator SG613 are shorted out. Darned, too expensive to try and fix, at least for me. Had a nice picture until the filament transformer opened, and then when I put the boards back into place, Poof, Smoke, well that was that. I don't know what happened or what I did to short them out. Didn't notice anything out of the ordinary when I put the boards back into place before I powered it up. Well, jstout (Jamie) can have it back or most likely it will be pitched in a dumpster somewhere.
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Old 07-08-2014, 08:59 PM
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ChrisW6ATV ChrisW6ATV is offline
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That is unfortunate. I recommend at least saving the CRT, since that one is known-good. With some real luck, maybe a set with a bad CRT and/or cabinet will be found that will have usable parts.
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Quote from another forum: "(Antique TV collecting) always seemed to me to be a fringe hobby that only weirdos did."
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  #6  
Old 07-09-2014, 06:55 PM
walterbeers walterbeers is offline
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DOES ANYBODY HAVE A COUPLE of good SPARE SG613s! Darned I hate to junk the set. Can't afford to put a lot of $ into a set that might just blow the darned things again. Maybe someone has an old Sony with a bad CRT that uses them. If so, let me know, my e-mail is wjb122750@hotmail.com or contact me on VK.
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  #7  
Old 07-09-2014, 07:07 PM
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maxhifi maxhifi is offline
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http://www.talonix.com/shop/item.asp...9#.U73ZAJm9LCQ
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  #8  
Old 07-10-2014, 08:42 AM
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zeno zeno is offline
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Quote:
Originally Posted by maxhifi View Post
Thats cheap & real OEM's.
That set may have been doomed already. When I did time at Sony
the color tech had just finished one. The HiFi man walked by
& gave it slap. Poof everything gone again He laughed
looked at me & said " thats why you dont want to be the color
TV man". I would find another set with a bad jug........

73 Zeno
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  #9  
Old 07-21-2014, 04:13 PM
wiseguy wiseguy is offline
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I have one of those sets, and had several over the years
you need to rsolder the pins on the CX-104 IC and anything around it that may look like cracks in the solder joints, there is also a few small Caps to replace ,the cx-104 is the horiz osc control and other things, there is a small pot to adjust h freq you need to clean it and rotate it then center it, also on the sweep section look for "GREEN" mylar type capacitors, the upgrade back then was new ones of the same value but they were Blue in color, Sony told us back then that if any capacitor is green in color it's mean, and if its blue in color its cool, in other words the blue versions were the updated ones, the green ones would short intermit and blow out the sg-613's, you should check for horiz osc by connecting a I think 15 volt Dc power supply to the test point they show in the manual and hookup a scope and look for proper waveform,
also there is a type of glue all over the board that becomes conductive and will kill the H-OSC which in turn kills the SG-613, you need to scrape off all of that brown glue on the boards,
its been a few years but I do remember servicing these things.
also that brown glue can cause the H-Freq to double and increase HV intermitly and kill the picture tube, you would hear the crack then arcing in the CRT
also this set has a HOT chassis ,use an isolation transformer when you have the cover off, anything with a ground or even a CATV connector touches the chassis will blow out the SG613's,
Good luck!
those are nice sets, really slim and flat

Last edited by wiseguy; 07-21-2014 at 04:24 PM.
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  #10  
Old 07-22-2014, 04:26 PM
walterbeers walterbeers is offline
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Well, right now the set is on hold. I still don't know what blew the SG613s. Somehow, for some reason, the set was working perfect, then all of a sudden a black screen, but the horizontal was running and it did have high voltage and sound. After checking things out, I found an open filament transformer which powers the CRT, so obviously no filament voltage to the CRT, no light on tube. Then I took the transformer out, found an open primary, powered the set up and put 6 volts to the filament pins of the CRT and presto, had a good picture. Thought, no big deal, I'll just find a new filament transformer. I folded the circuit boards back into place, and tried powering it up again, and poof, "smoke", R608 went. Well both SG613s went dead short, (bye,bye) SG613s. Don't know what happened, what did I do? Maybe something shorted, or messed up when I folded the boards back in. Thanks wiseguy for the advice. With this in mind, I might just order them, and give the set another try. Even if I get the HV going again, I still have to find the filament transformer. Wonder if I can just use a standard 120 volt to 6 volt transformer? Everything with these sets seem to require original Sony parts.
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  #11  
Old 07-23-2014, 06:39 AM
wiseguy wiseguy is offline
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that's the thing on these boards if cracked solder Joints, and that Glue that is on both sides of the sweep board, once the boards have been flexed then all sort of things intermit will happen, the loss of H-Drive being intermit will blow all those parts exactly, the trick is powering up the Drive Circuit with only a 15-19 volt DC low voltage power supply and monitoring the drive with a scope and tapping all over the board while watching the waveform for changes, then resoldering, if I remember the H drive transistor is a 2sc1614 or 2sc1416 (forget) it is a larger plastic case Transistor
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  #12  
Old 03-15-2024, 09:39 PM
thomashjr thomashjr is offline
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Maybe reviving old thread here...I just got this complete set with chassis ssc-41a-b with little known history. 4A fuse on PS board is open but 5A one still intact. I have the big capacitors on that board on the way. I have read about sg608 and sg613 TVs; this one has a SG608 in plain sight on the PS board. Is that the H output or V output or something completely different? If someone on here can share a PDF of the schematic, thank you. chassis is scc-41a-b

Last edited by thomashjr; 03-16-2024 at 01:08 PM.
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