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the fixer Guest
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Posted: Sat May 02, 2009 9:07 am Post subject: E_w problem |
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Hello every one ,i have Grundig model 63-660NIC .After changing horiz.tranistor a problem of East West problem appeared(the edges of screen are small black curved shape).any one to guide me find what is wrong with this.Thaks in advance |
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jts1957
Joined: 24 Nov 2008 Posts: 2476 Location: Far, Far Away
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Posted: Sat May 02, 2009 9:15 am Post subject: |
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Sounds like "Pincushion." Check components in that circuit. |
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thefixer Guest
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Posted: Sat May 02, 2009 12:32 pm Post subject: e w problem |
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what do you mean by "pincushion" could plz explain more.thanks in advance. |
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Justmanuals
Joined: 21 Aug 2004 Posts: 1948
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Posted: Sat May 02, 2009 12:51 pm Post subject: |
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How is it that you were able to change a horizontal transistor but you don't know what the 'pincushion' effect is? I'm not a TV tech and I know what it is. Google it.
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thefixer Guest
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Posted: Sat May 02, 2009 3:14 pm Post subject: EWproblem |
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hello every one ! i am not good at english that's why i can say it in french ,is it " court circuit".thanks for appreciation. |
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jts1957
Joined: 24 Nov 2008 Posts: 2476 Location: Far, Far Away
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Posted: Sat May 02, 2009 5:36 pm Post subject: |
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It is NOT:
A pincushion (or less commonly pin cushion) is a small cushion, typically 3-5 cm across, which is used in sewing to store pins or needles ... |
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thefixer Guest
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Posted: Sat May 02, 2009 7:26 pm Post subject: E W problem |
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what's the relation ship between "pincushion" and East west problem? |
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jts1957
Joined: 24 Nov 2008 Posts: 2476 Location: Far, Far Away
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Posted: Sat May 02, 2009 7:46 pm Post subject: |
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Quote: | Pincushion distortion is a common type of distortion in CRT monitors in which horizontal and vertical lines bend inwards toward the center of the display. The distortion is most noticeable at the edges of the display. Pincushion distortion is a divergence from the rectilinear projection in geometric optics where image magnification increases with increasing distance from the optical axis. | |
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thefixer Guest
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Posted: Sat May 02, 2009 9:54 pm Post subject: E w problem |
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thanks ,so i have to check every componet there it may be capacitor resistor etc....is there any special component which is responsible for this problem.any why i try to replace any componet i doubt.thanks again for explanation. |
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torbjorn
Joined: 07 Jun 2007 Posts: 370 Location: Sweden
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Posted: Tue May 05, 2009 7:57 am Post subject: |
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If the E/W correction is made by a diode modulator, first check both diodes and the capacitors parallel to them. It is very important that those diodes are of the correct type, parameters like recovery time and so on must match those of the original diodes. Slow diodes intended for mains rectifiers will not work as E/W diodes even if their voltage and current ratings are correct.
Also, it is common that components connected to the midpoint between the diodes fail. In many cases there is a fusible resistor, or it might be a coil that can get overheated. The modulator driver - usually a small power transistor or an IC, can also get damaged.
If there is a coil with adjustable core in the E/W circuitry, you should after repairing the fault make sure that it is correctly adjusted (refer to the service manual for the chassis). |
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