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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Hi,
I got a TV from somebody, a Sony KV-32WS3D (chassis AE-3) The upper corners are very colored, see this picture from a teletext page which should only contain the colors white and blue: http://img182.imageshack.us/img182/6980/dsc03030pg9.jpg I checked the degauss coils: OK, PTC also OK, the degauss sound can be heard when the unit is switched on The deflection yoke was a little bit loose, when I moved it on the neck of the CRT the colors on the screen are changing but I cannot get the right colors in the upper corners, in every position of the yoke, very strange.... There are no magnets from e.g. speakers in the neighbourhood. The support rubbers for the yoke are still in place except one. But in every position of the yoke there are colored upper corners.... There are more coils around the CRT: rotation coil. After disconnecting this one, still bad colors Another coil is connected to a small PCB at the right side of the chassis. Near the connector I read: CY+ and CY- Is this a convergence coil? Convergence is still OK, only that colored corners... (oh yes, sometimes several channels are not showing picture, only snow or a snowy picture) After a while the picture comes back. I think a bad contact inside the tuner....) I cannot believe there is something wrong with the CRT itself..... Regards, Arjan |
#2
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On 6 feb, 17:26, Arjan wrote:
Hi, I got a TV from somebody, a Sony KV-32WS3D (chassis AE-3) The upper corners are very colored, see this picture from a teletext page which should only contain the colors white and blue:http://img182.imageshack.us/img182/6980/dsc03030pg9.jpg I checked the degauss coils: OK, PTC also OK, the degauss sound can be heard when the unit is switched on The deflection yoke was a little bit loose, when I moved it on the neck of the CRT the colors on the screen are *changing but I cannot get the right colors in the upper corners, in every position of the yoke, very strange.... There are no magnets from e.g. speakers in the neighbourhood. The support rubbers for the yoke are still in place except one. But in every position of the yoke there are colored upper corners.... There are more coils around the CRT: rotation coil. After disconnecting this one, still bad colors Another coil is connected to a small PCB at the right side of the chassis. Near the connector I read: CY+ and CY- *Is this a convergence coil? Convergence is still OK, only that colored corners... (oh yes, sometimes several channels are not showing picture, only snow or a snowy picture) After a while the picture comes back. I think a bad contact inside the tuner....) I cannot believe there is something wrong with the CRT itself..... Regards, Arjan correct link to the pictu http://img182.imageshack.us/my.php?i...sc03030pg9.jpg |
#3
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On Feb 6, 12:03*pm, Arjan wrote:
On 6 feb, 17:26, Arjan wrote: Hi, I got a TV from somebody, a Sony KV-32WS3D (chassis AE-3) The upper corners are very colored, see this picture from a teletext page which should only contain the colors white and blue:http://img182.imageshack.us/img182/6980/dsc03030pg9.jpg I checked the degauss coils: OK, PTC also OK, the degauss sound can be heard when the unit is switched on The deflection yoke was a little bit loose, when I moved it on the neck of the CRT the colors on the screen are *changing but I cannot get the right colors in the upper corners, in every position of the yoke, very strange.... There are no magnets from e.g. speakers in the neighbourhood. The support rubbers for the yoke are still in place except one. But in every position of the yoke there are colored upper corners.... There are more coils around the CRT: rotation coil. After disconnecting this one, still bad colors Another coil is connected to a small PCB at the right side of the chassis. Near the connector I read: CY+ and CY- *Is this a convergence coil? Convergence is still OK, only that colored corners... (oh yes, sometimes several channels are not showing picture, only snow or a snowy picture) After a while the picture comes back. I think a bad contact inside the tuner....) I cannot believe there is something wrong with the CRT itself..... Regards, Arjan correct link to the pictuhttp://img182.imageshack.us/my.php?i...c03030pg9.jpg- Hide quoted text - - Show quoted text - It is quite possible something is magnetized that is not within the area of the internal degaussing coils. Try a strong magnet near the worst corner and rotate it rapidly and continually while moving it away from the set until you can't see any effect of the picture color in the corner, Then move an additional 3 feet away before stopping the rotating. See if that helps at all, then also degauss the set again. Do that degaussing after the set has been idle/off for at least 30 minutes to allow the degaussing components to start cold. I personally always use an external degaussing coil whenever I am at all suspicious about the interrnal cois as they do not put out a really strong degaussing fiield. Please post the results. |
#5
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Arjan
I've had this problem with Sony sets having bad purity on the lower left corner. Moving the set around the room to realign relative to the Earth's magnetic field only helped a little. Yes, in this case, it was the tube, it had to be replaced. Colin Arjan wrote: On 6 feb, 17:26, Arjan wrote: Hi, I got a TV from somebody, a Sony KV-32WS3D (chassis AE-3) The upper corners are very colored, see this picture from a teletext page which should only contain the colors white and blue:http://img182.imageshack.us/img182/6980/dsc03030pg9.jpg I checked the degauss coils: OK, PTC also OK, the degauss sound can be heard when the unit is switched on The deflection yoke was a little bit loose, when I moved it on the neck of the CRT the colors on the screen are changing but I cannot get the right colors in the upper corners, in every position of the yoke, very strange.... There are no magnets from e.g. speakers in the neighbourhood. The support rubbers for the yoke are still in place except one. But in every position of the yoke there are colored upper corners.... There are more coils around the CRT: rotation coil. After disconnecting this one, still bad colors Another coil is connected to a small PCB at the right side of the chassis. Near the connector I read: CY+ and CY- Is this a convergence coil? Convergence is still OK, only that colored corners... (oh yes, sometimes several channels are not showing picture, only snow or a snowy picture) After a while the picture comes back. I think a bad contact inside the tuner....) I cannot believe there is something wrong with the CRT itself..... Regards, Arjan correct link to the pictu http://img182.imageshack.us/my.php?i...sc03030pg9.jpg |
#6
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Suggest getting the SONY Service literature for the item and then attempt
both purity and registration setup. Confirm the arpeture grill assembly is not loose, lightly tapping on the screen while displaying a solid colour. Appropiate positioning of the convergence yoke including spacing wedges will resolve most of the purity issues, spot magnets properly installed will clear up the corners. Once purity is considered proper then you can attempt the convergence, pincushion, keystone, etc. Be advised, there is no quick dirty fix to the problem. Attemping to degauss the crt with external means can actually permantly damage the arpeture grill assembly rendering the crt not repairable, Per SONY DATUM! Correct adjustments can take up to two hours for even trained professionals. "Colin McCormick" wrote in message ... Arjan I've had this problem with Sony sets having bad purity on the lower left corner. Moving the set around the room to realign relative to the Earth's magnetic field only helped a little. Yes, in this case, it was the tube, it had to be replaced. Colin Arjan wrote: On 6 feb, 17:26, Arjan wrote: Hi, I got a TV from somebody, a Sony KV-32WS3D (chassis AE-3) The upper corners are very colored, see this picture from a teletext page which should only contain the colors white and blue:http://img182.imageshack.us/img182/6980/dsc03030pg9.jpg I checked the degauss coils: OK, PTC also OK, the degauss sound can be heard when the unit is switched on The deflection yoke was a little bit loose, when I moved it on the neck of the CRT the colors on the screen are changing but I cannot get the right colors in the upper corners, in every position of the yoke, very strange.... There are no magnets from e.g. speakers in the neighbourhood. The support rubbers for the yoke are still in place except one. But in every position of the yoke there are colored upper corners.... There are more coils around the CRT: rotation coil. After disconnecting this one, still bad colors Another coil is connected to a small PCB at the right side of the chassis. Near the connector I read: CY+ and CY- Is this a convergence coil? Convergence is still OK, only that colored corners... (oh yes, sometimes several channels are not showing picture, only snow or a snowy picture) After a while the picture comes back. I think a bad contact inside the tuner....) I cannot believe there is something wrong with the CRT itself..... Regards, Arjan correct link to the pictu http://img182.imageshack.us/my.php?i...sc03030pg9.jpg |
#7
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Meat Plow wrote:
Heh I've used a Weller 140 watt gun to degauss. I wound my own degaussing coils about 40 years ago. You could see the CRT flicker at 20 feet when it was tuned on, and turned to face the CRT. I make a bunch of them and sold all but one of them. They had 20 foot power cords and a heavy duty industrial chrome push button so you didn't accidentally leave it turned on. I still have the one. they were made with surplus 17 AWG DE/DC magnet wire. They were wound on a plywood jig, then tied off and covered with two layers of 3M #66 electrical tape. The switch was mounted on a curved aluminum plate, wired to the coil and cord, then the plate was over wrapped with more tape. -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida |
#8
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On 7 feb, 22:12, "Michael A. Terrell"
wrote: Meat Plow wrote: Heh I've used a Weller 140 watt gun to degauss. * *I wound my own degaussing coils about 40 years ago. You could see the CRT flicker at 20 feet when it was tuned on, and turned to face the CRT. *I make a bunch of them and sold all but one of them. They had 20 foot power cords and a heavy duty industrial chrome push button *so you didn't accidentally leave it turned on. *I still have the one. *they were made with surplus 17 AWG DE/DC magnet wire. *They were wound on a plywood jig, then tied off and covered with two layers of 3M #66 electrical tape. *The switch was mounted on a curved aluminum plate, wired to the coil and cord, then the plate was over wrapped with more tape. I cannot imagine that the CRT is so magnetized..... The TV did not have this problems when it still was at the owner where I got this TV set from... I only dismounted it and cleaned it with a vacuum cleaner, because it was very dirty and dusty inside. The original problem was that vertical black and white bars were visible in the picture, even without input signal. This was caused by a bad capacitor in the power supply line of the video amp. But after replacing of the cap it turned out that the corners of the picture where colored.... Can it be a loose contact somewhere from a coil? I checked all the plugs and they are all fitted OK. It was maybe a good idea to turn the set on before dismounting.... Transportation went without problems, the set was not put down very hard. I moved the set around the room, but the color spots are still there..... |
#9
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![]() "Arjan" wrote in message ... On 7 feb, 22:12, "Michael A. Terrell" wrote: I cannot imagine that the CRT is so magnetized..... snip The tube can pick up enough residual magnetism to cause your problem simply from being moved. They are very sensitive this way (the Earth's magnetic field is the cause of this phenomenon) but in case it wasn't mentioned earlier, make sure there are no speakers near the TV. It's also possible that the degauss circuit has failed or a correction magnet has fallen off the tube, or somehow the purity rings got jostled. Mark Z. |
#10
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Meat Plow wrote:
On Thu, 07 Feb 2008 16:12:29 -0500, Michael A. Terrell wrote: Meat Plow wrote: Heh I've used a Weller 140 watt gun to degauss. I wound my own degaussing coils about 40 years ago. You could see the CRT flicker at 20 feet when it was tuned on, and turned to face the CRT. I make a bunch of them and sold all but one of them. They had 20 foot power cords and a heavy duty industrial chrome push button so you didn't accidentally leave it turned on. I still have the one. they were made with surplus 17 AWG DE/DC magnet wire. They were wound on a plywood jig, then tied off and covered with two layers of 3M #66 electrical tape. The switch was mounted on a curved aluminum plate, wired to the coil and cord, then the plate was over wrapped with more tape. Wow I bet those kicked some ass. I bought one in the mid 70's from a friend who did RCA repair. It was one of the good old ones and I still own it although I haven't used it in some time. I'll post some pictures when I dig it out. I've forgot how much copper it has. You could not only degauss a TV set, you could demagnetize hand tools, and wrist watches. ![]() -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida |
#11
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![]() "Michael A. Terrell" wrote in message ... Meat Plow wrote: On Thu, 07 Feb 2008 16:12:29 -0500, Michael A. Terrell wrote: Meat Plow wrote: Heh I've used a Weller 140 watt gun to degauss. I wound my own degaussing coils about 40 years ago. You could see the CRT flicker at 20 feet when it was tuned on, and turned to face the CRT. I make a bunch of them and sold all but one of them. They had 20 foot power cords and a heavy duty industrial chrome push button so you didn't accidentally leave it turned on. I still have the one. they were made with surplus 17 AWG DE/DC magnet wire. They were wound on a plywood jig, then tied off and covered with two layers of 3M #66 electrical tape. The switch was mounted on a curved aluminum plate, wired to the coil and cord, then the plate was over wrapped with more tape. Wow I bet those kicked some ass. I bought one in the mid 70's from a friend who did RCA repair. It was one of the good old ones and I still own it although I haven't used it in some time. I use a degaussing coil I salvaged from a junk TV and put a power cord on. It gets hot in a hurry, two in series and attached together would probably be a better idea. You can bundle them into a more compact circle than they were originally. |
#12
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James Sweet wrote:
I use a degaussing coil I salvaged from a junk TV and put a power cord on. It gets hot in a hurry, two in series and attached together would probably be a better idea. You can bundle them into a more compact circle than they were originally. I think I used 200 turns of 17 AWG on a 12 inch form. It HAS been almost 40 years. ![]() -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida |
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