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Title: NEOTEC NT-500DX Schematic Post by: racergiant on September 16, 2008, 06:35:34 AM Started by aibudo -
NEOTEC NT-500DX Schematic Have unusual vertical deflection problem with this unit. The vertical will adjust properly, but it has oscillations occuring within the raster. Horizontal black lines all over the screen, with the colorbar test pattern ok. Have serviced monitors for several years but haven't seen this before. Dennis Title: Re: NEOTEC NT-500DX Schematic Post by: KirkLasVegas on September 19, 2008, 01:40:18 PM Dennis,
Look at the power supply voltages at each chip with a scope. i suspect you will see rippling there due to a open power supply bypass cap and the digital noise is spreading thru the "Bus" on the board itself. You wont see this at the supply due to it's low impedance.Measure this on the "Vcc" pin of the chips in the vertical deflection area first. The verticle deflection circuits are power hogs. Highly suspect ANY 1Mfd to 10Mfd electrolytics used as bypass caps, as they dry out and lose their value. Kirk Title: Re: NEOTEC NT-500DX Schematic Post by: FunExpo on October 15, 2011, 01:35:55 PM I am having the a Similar Power issue mine did a blue tent to screen first then lost all power could you tell me where this Bypass cap is located I have metered across my Caps and all seem to be within Spec. for the cap. Any help would be appreciated have a great day..
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