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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 cw28 crt tv - blanking problem?
Hi there, was wondering if anyone could offer any words of advice on
the following problem: replaced the LOPTX /flyback in this 100hz tv (S53A chassis), set now powers up but no picture, only a few strips of white light near the very top of the screen. slowly cranking up the screen control brings up a raster, a clear picture but with visible retrace lines. By backing off on the screen control at this point, it is possible to remove them, but on power up once more the set blanks the video. My question is: is there likely to be a setting in the service menu which could resolve this or have I got a duff line transformer/some other component? I have replaced the caps in the 200v feed to the RGB to no avail. regards, Ben |
#2
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samsung cw28 crt tv - blanking problem?
Scope video signals going to the crt panel, check the B+ and G2 levels at
the appropriate test points. Confirm that are no solder splashes, cracked or open connections. These shutdown problems may necessitate using the service manuals available from Samsung. Check the feedback circuits into the protect (OVP,OCP, Etc) may have a flakey diode or transistor, etc, or maybe just lousy soldering (Manufacturing Induced). . "b" wrote in message oups.com... Hi there, was wondering if anyone could offer any words of advice on the following problem: replaced the LOPTX /flyback in this 100hz tv (S53A chassis), set now powers up but no picture, only a few strips of white light near the very top of the screen. slowly cranking up the screen control brings up a raster, a clear picture but with visible retrace lines. By backing off on the screen control at this point, it is possible to remove them, but on power up once more the set blanks the video. My question is: is there likely to be a setting in the service menu which could resolve this or have I got a duff line transformer/some other component? I have replaced the caps in the 200v feed to the RGB to no avail. regards, Ben |
#3
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samsung cw28 crt tv - blanking problem?
Art wrote: Scope video signals going to the crt panel, check the B+ and G2 levels at the appropriate test points. Confirm that are no solder splashes, cracked or open connections. These shutdown problems may necessitate using the service manuals available from Samsung. Check the feedback circuits into the protect (OVP,OCP, Etc) may have a flakey diode or transistor, etc, or maybe just lousy soldering (Manufacturing Induced). . "b" wrote in message oups.com... Hi there, was wondering if anyone could offer any words of advice on the following problem: replaced the LOPTX /flyback in Thanks Art, don't have a scope but you've given me a few pointers. However, there isn't a 'shutdown problem' as such, just that it seems to me that either the g2 is too high or the blanking circuit is faulty. -B. |
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