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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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Samsung TV convergence problems
Hello everyone:
I have a samsung projection tv model no: HCN4727W The convergence is off as it does not let me adjust blue, and while red adjusts fine, it is warped at the top and bottom. I pulled the convergence board, and it appears that the two IC units have been replaced at least once in the TV's lifetime (I just got the tv and have no idea of its prior history). Also, the repairman soldered pins 1,2, and 3 of both IC units in line with a resistor (or maybe a diode I'm not sure), and then connected the resistor to the -20v terminal on the board. I'm not sure why this modification would be necessary, as it appears the IC chips are OEM (they're both STK392-040). Anyways, I was thinking of just replacing the entire unit (board and all) and seeing what happens. Good or bad idea? http://www.samsungparts.com/part_det...model=HCN4727W Mike |
#2
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Samsung TV convergence problems
On Nov 4, 12:10 pm, Meat Plow wrote:
On Sun, 04 Nov 2007 08:40:49 -0800, 97tjMike wrote: Hello everyone: I have a samsung projection tv model no: HCN4727W The convergence is off as it does not let me adjust blue, and while red adjusts fine, it is warped at the top and bottom. I pulled the convergence board, and it appears that the two IC units have been replaced at least once in the TV's lifetime (I just got the tv and have no idea of its prior history). Also, the repairman soldered pins 1,2, and 3 of both IC units in line with a resistor (or maybe a diode I'm not sure), and then connected the resistor to the -20v terminal on the board. I'm not sure why this modification would be necessary, as it appears the IC chips are OEM (they're both STK392-040). Anyways, I was thinking of just replacing the entire unit (board and all) and seeing what happens. Good or bad idea? Probably a good idea especially if you don't know the difference between a resistor and a diode. ah well i know their difference functionality wise, just not appearance wise. i'd call it a resistor except it has a glossy coating common to diodes |
#3
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Samsung TV convergence problems
"97tjMike" wrote in message
ups.com... On Nov 4, 12:10 pm, Meat Plow wrote: On Sun, 04 Nov 2007 08:40:49 -0800, 97tjMike wrote: Probably a good idea especially if you don't know the difference between a resistor and a diode. ah well i know their difference functionality wise, just not appearance wise. i'd call it a resistor except it has a glossy coating common to diodes I believe the Mr. Plow was not trying to be lightly humorous, but was being sarcastic at your expense. |
#4
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Samsung TV convergence problems
In article ,
"William Sommerwerck" wrote: "97tjMike" wrote in message ups.com... On Nov 4, 12:10 pm, Meat Plow wrote: On Sun, 04 Nov 2007 08:40:49 -0800, 97tjMike wrote: Probably a good idea especially if you don't know the difference between a resistor and a diode. ah well i know their difference functionality wise, just not appearance wise. i'd call it a resistor except it has a glossy coating common to diodes I believe the Mr. Plow was not trying to be lightly humorous, but was being sarcastic at your expense. I believe the Mr. Plow was being neither sarcastic nor humorous, but merely matter-of-fact. Tis a rare individual who knows the theoretical difference between a resistor and a diode but cannot properly distinguish the two. Nevertheless, the OP is clearly unqualified to troubleshoot to the component level. |
#5
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Samsung TV convergence problems
Cost of the replacment board via Samsung would probably be less investment
than troubleshooting the original pcb. IMHO Smitty Two" wrote in message news In article , "William Sommerwerck" wrote: "97tjMike" wrote in message ups.com... On Nov 4, 12:10 pm, Meat Plow wrote: On Sun, 04 Nov 2007 08:40:49 -0800, 97tjMike wrote: Probably a good idea especially if you don't know the difference between a resistor and a diode. ah well i know their difference functionality wise, just not appearance wise. i'd call it a resistor except it has a glossy coating common to diodes I believe the Mr. Plow was not trying to be lightly humorous, but was being sarcastic at your expense. I believe the Mr. Plow was being neither sarcastic nor humorous, but merely matter-of-fact. Tis a rare individual who knows the theoretical difference between a resistor and a diode but cannot properly distinguish the two. Nevertheless, the OP is clearly unqualified to troubleshoot to the component level. |
#6
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Samsung TV convergence problems
I have not worked on that model myself. But, most of the time the failures
are the driver IC's, bias resistors and caps. If available, some of the service techs will replace the complete convergence board. Considering the age of the set, and the fact that it uses tube technology for the display, maybe you should consider something up to date and dependable rather than chase the faults in this one. -- JANA _____ "97tjMike" wrote in message ups.com... Hello everyone: I have a samsung projection tv model no: HCN4727W The convergence is off as it does not let me adjust blue, and while red adjusts fine, it is warped at the top and bottom. I pulled the convergence board, and it appears that the two IC units have been replaced at least once in the TV's lifetime (I just got the tv and have no idea of its prior history). Also, the repairman soldered pins 1,2, and 3 of both IC units in line with a resistor (or maybe a diode I'm not sure), and then connected the resistor to the -20v terminal on the board. I'm not sure why this modification would be necessary, as it appears the IC chips are OEM (they're both STK392-040). Anyways, I was thinking of just replacing the entire unit (board and all) and seeing what happens. Good or bad idea? http://www.samsungparts.com/part_det...model=HCN4727W Mike |
#7
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Samsung TV convergence problems
On Nov 4, 1:00 pm, Smitty Two wrote:
In article , "William Sommerwerck" wrote: "97tjMike" wrote in message oups.com... On Nov 4, 12:10 pm, Meat Plow wrote: On Sun, 04 Nov 2007 08:40:49 -0800, 97tjMike wrote: Probably a good idea especially if you don't know the difference between a resistor and a diode. ah well i know their difference functionality wise, just not appearance wise. i'd call it a resistor except it has a glossy coating common to diodes I believe the Mr. Plow was not trying to be lightly humorous, but was being sarcastic at your expense. I believe the Mr. Plow was being neither sarcastic nor humorous, but merely matter-of-fact. Tis a rare individual who knows the theoretical difference between a resistor and a diode but cannot properly distinguish the two. Nevertheless, the OP is clearly unqualified to troubleshoot to the component level. I wouldn't concern yourself with my lack of expertise so much. I have and EE friend who I'm working with. Just didn't have a chance to have him look at the board before I posted this. After having him looking at the board, we found that they are indeed diodes, and they are soldered to pins 1-3, which, according to a schematic of the ICs which we found online, pins 1-3 are not connected to anything. That's why I'm very curious why someone would put an diode to those terminals. But anyways we're gonna try to replace the IC units themselves (and omit the diodes), because from what I've read elsewhere it seems that the ICs tend to fail frequently. |
#8
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Samsung TV convergence problems
On Nov 5, 10:41 am, Meat Plow wrote:
On Sun, 04 Nov 2007 21:52:44 -0800, 97tjMike wrote: On Nov 4, 1:00 pm, Smitty Two wrote: In article , "William Sommerwerck" wrote: "97tjMike" wrote in message oups.com... On Nov 4, 12:10 pm, Meat Plow wrote: On Sun, 04 Nov 2007 08:40:49 -0800, 97tjMike wrote: Probably a good idea especially if you don't know the difference between a resistor and a diode. ah well i know their difference functionality wise, just not appearance wise. i'd call it a resistor except it has a glossy coating common to diodes I believe the Mr. Plow was not trying to be lightly humorous, but was being sarcastic at your expense. I believe the Mr. Plow was being neither sarcastic nor humorous, but merely matter-of-fact. Tis a rare individual who knows the theoretical difference between a resistor and a diode but cannot properly distinguish the two. Nevertheless, the OP is clearly unqualified to troubleshoot to the component level. I wouldn't concern yourself with my lack of expertise so much. I have and EE friend who I'm working with. Just didn't have a chance to have him look at the board before I posted this. After having him looking at the board, we found that they are indeed diodes, and they are soldered to pins 1-3, which, according to a schematic of the ICs which we found online, pins 1-3 are not connected to anything. That's why I'm very curious why someone would put an diode to those terminals. But anyways we're gonna try to replace the IC units themselves (and omit the diodes), because from what I've read elsewhere it seems that the ICs tend to fail frequently. If they are serviced correctly, those devices shouldn't fail frequently. I found that on my 2000 Panasonic 53" TV they failed earlier this year because the mounting screws were not tight. I don't know if they were not tight from the factory or somehow from heat cool cycles managed to loosen on their own. Regardless if properly installed and there are no other hidden problems, the repeat failure rate should be fairly low. Remember to use original factory parts and not OEM. Those devices are probably the hardest working electronics in the entire set. here's a followup: we replaced the two IC chips in the board, and,while the colors seem to be more well definied, the blue convergence still will not adjust. We were able to adjust the focus on the picture tube, so focus is no longer an issue. However, the convergence problem still occurs. Should we replace the 1st convergence board (not the one with the IC chips.)? Just looking for reccomendations. Thanks http://cgi.ebay.com/ws/eBayISAPI.dll...ksid=p3907.m29 |
#9
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Samsung TV convergence problems
"97tjMike" wrote in message oups.com... On Nov 5, 10:41 am, Meat Plow wrote: On Sun, 04 Nov 2007 21:52:44 -0800, 97tjMike wrote: On Nov 4, 1:00 pm, Smitty Two wrote: In article , "William Sommerwerck" wrote: "97tjMike" wrote in message oups.com... On Nov 4, 12:10 pm, Meat Plow wrote: On Sun, 04 Nov 2007 08:40:49 -0800, 97tjMike wrote: Probably a good idea especially if you don't know the difference between a resistor and a diode. ah well i know their difference functionality wise, just not appearance wise. i'd call it a resistor except it has a glossy coating common to diodes I believe the Mr. Plow was not trying to be lightly humorous, but was being sarcastic at your expense. I believe the Mr. Plow was being neither sarcastic nor humorous, but merely matter-of-fact. Tis a rare individual who knows the theoretical difference between a resistor and a diode but cannot properly distinguish the two. Nevertheless, the OP is clearly unqualified to troubleshoot to the component level. I wouldn't concern yourself with my lack of expertise so much. I have and EE friend who I'm working with. Just didn't have a chance to have him look at the board before I posted this. After having him looking at the board, we found that they are indeed diodes, and they are soldered to pins 1-3, which, according to a schematic of the ICs which we found online, pins 1-3 are not connected to anything. That's why I'm very curious why someone would put an diode to those terminals. But anyways we're gonna try to replace the IC units themselves (and omit the diodes), because from what I've read elsewhere it seems that the ICs tend to fail frequently. If they are serviced correctly, those devices shouldn't fail frequently. I found that on my 2000 Panasonic 53" TV they failed earlier this year because the mounting screws were not tight. I don't know if they were not tight from the factory or somehow from heat cool cycles managed to loosen on their own. Regardless if properly installed and there are no other hidden problems, the repeat failure rate should be fairly low. Remember to use original factory parts and not OEM. Those devices are probably the hardest working electronics in the entire set. here's a followup: we replaced the two IC chips in the board, and,while the colors seem to be more well definied, the blue convergence still will not adjust. We were able to adjust the focus on the picture tube, so focus is no longer an issue. However, the convergence problem still occurs. Should we replace the 1st convergence board (not the one with the IC chips.)? Just looking for reccomendations. Thanks http://cgi.ebay.com/ws/eBayISAPI.dll...ksid=p3907.m29 Sometimes there are fuses (pico-fuses) or resistors associated with the STK's which are bad also... Mark Z. |
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