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#1
10-10-2014, 01:47 PM
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Sanyo Chassis #G5Y-3258GO
This set just developed a horizontal white line across teh screen,,,happened this morning, and again just now,,, Searching finds to to most likely be a loose connection, damaged trace or bad cap in teh vertical section...
I hang out in teh audio tube forum, and found this one for TVs... Is there any place to down load a schematic for this set? I may be able to track down the problem, if I knew where to look... Right now it has a good, clear picture, but, I believe it won't last... Any help is appreciated.. Regards, John 
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#4
10-10-2014, 10:46 PM
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Yep, cold solder joints on the vertical output IC - very common problem. While you have it apart, replace the 100uf (or 220uf) capacitor that's right by the vertical IC and use a good quality brand (Nichicon, Panasonic) with a 105 degree temperature rating. This cap is also a very common failure and when it starts to go south, you'll get lines and/or foldover at the top of the screen. As the capacitor gets worse, it will take out the IC and possibly other parts in the vertical circuit. When I was fixing a lot of TV's for people, they'd usually run the set until the vertical IC blew up; which, caused the set to display only a thin horizontal line. Had they brought me the set when it first started acting up, the repair would have been easier and cheaper.
__________________
http://www.youtube.com/user/radiotvphononut
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#5
10-11-2014, 08:26 AM
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Thanks for replies,,, I found flexing board slightly restores teh connection,and a small block under teh HV transformer keeps it on, I'm sure it is a cold solder joint, just not sure what components are affected... schem would help, but none seem to be available,,,
I realize its a low value set, but fixing it would be easier than moving it around alone... Here are a few board pics... Thanks again for the help, point me to teh components, and I will see about reflowing/ or changing them... Regards, John
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#6
10-11-2014, 09:00 AM
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The heatsink towards the right rear of the chassis looks to have the vertical out. IC on it. THIS is the part that needs resoldered. I see 2 electrolytic capacitors near the vertical IC. ONE of them is likely a 100/35, maybe a 220/35 and you should also replace it--as has been pointed out. By this time--it has been stresses enough--and will fail soon one way or another. Since it is already open--replace that cap--it is VERY cheap insurance. You are looking for a cap with this value that is connected to the IC, one end will also be connected to a diode. This is known as the "pump up" or "boost" capacitor" and it basically helps to "recover" otherwise wasted energy from the yoke---and the energy is then used to drive the output ckt.
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#7
10-11-2014, 09:43 AM
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Thanks for teh quick reply,,, Guess I dont have this forum set to send Email when a post is updated,,,
I couldn't get a couple of teh plugs out of teh board to get it out to teh bench, but there is enough slack to flip it over and work on in place... This board is over a foot wide and is only supported on teh sides, in slots, Its gotta bend and break connections/traces sooner or later,,, If I can identify teh IC, I'll try to reflow it,,, I should have a few low voltage caps, so I'll see about that one also...Maybe then it will last long enough to find a replacement set... Thanks again for teh info/help... Regards, John
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#8
10-11-2014, 09:59 AM
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Just opened it up, looking at board from teh back, HV tx is on Right side rear, and there are heatsinks behind it, towards teh front of set...seems IC are on teh opposite side, Rear, mounted to board, no heat sinks,,,, not sure what I'm looking for at this point,,,
Regard, John
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#9
10-11-2014, 10:57 AM
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A few more hints that may help........
Most sets number the parts in blocks example hoz 500 series vert 400 series IF 100 series so you can ID what circuit they are in example is T501 is in hoz & is usually the horz drive transformer ETC. Looking at photo rear to front looks like Flyback ( FBT) Horz output transistor ( HOT ) on heat sink Hoz drive transformer, pin & yoke components. Vert out IC on sink Power supply is to the left, switching transformer then in front the switching FET or transistor on sink. In front of vert IC looks like audio out IC on sink. To service unplug yoke, speakers, degaus coil, loosen wire ties & flip over chassis. Now you can see everything & the solder will flow nicely ! Have fun, wish I were there to work on it ! 73 Zeno 
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#10
10-11-2014, 11:10 AM
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Quote:
Yep wish you were closer also, at least we could move the thing!!! Just got a cap order in teh mail, maybe I should go work on the tube amp, I've been building,,, I'll take another look at it, and see if I can find a IC with a 400 series code in that vicinity.... Regards, John
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| Audiokarma |
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#11
10-11-2014, 12:56 PM
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Got it!!!
Thanks to all for putting up with a TV rookie!!! Found a 7 pin chip, I thought was a transistor, with most of teh leads loose, re- soldered it, and its running now,,, Didn't locate the caps you were talking about, but I didn't get the board all the way out of teh set, some of the small plugs wouldn't come loose, so I did it in place...put the 2x4 back in tho, to support the board, real bad design there... Just wish I could see better, three pair of glasses, but it may last until I get help to move it... If I find a schematic, I may change a few caps, but the board may not want another operation!!!!! Thanks again,,, You guys are as helpful as the tube forum guys !!!!!! Regards, John
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#12
10-11-2014, 02:30 PM
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Nice work !
 Now go find a few more we can work on. BTW the boards look flimsy but they do take a beating. Once you get used to it you can really toss them around like a seasoned pro. And remember most brands from abt 1985-2000 get the same problems & if you learn one you learn the others. 73 Zeno
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#13
10-11-2014, 03:46 PM
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Quote:
Hasn't missed a beat in the last couple hours, got it on a music channel, nothing to watch!!! They forgot the 2x4 tho,,, Nope, you can have em all!, this was just too heavy to haul out alone, did the next best thing... There is an old Sony around from the late 70s or 80s, doesn't work at all, tried it yesterday when this one quit,,, Fuse is good, that's as far as I got... I'll stick to tube amps, at least I can see em!!!! Regards, John
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