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| Huamei Universal FBT/ Flyback Transformer A29 |
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Published：2011/9/5 12:26:23 Hit：7847 |
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Huamei Universal FBT/ Flyback Transformer Service Manual
Ⅰ、General Theories
Huamei Uniersal FBT is actually a line output transformer with high voltage output and complete genres.Refer to Figure 1 for internal principles.
From Figure 1 we can see that Color TV line output voltage is comparatively high in compliance with requirement of most color TVs.Therefore,as long as there is appropriate connection pin,it is reliable to replace Color TV's line of original machine.
Ⅱ、Connection Method
Figure 2 is a description drawing of this Color TV line,with two circle of pins inside and outside,in which pins at internal circle are shorter,these are leding feet of internal functions;pins at outer circle are longer,these are all empty pins.During application.make different connections among pins of internal circle and outer circle,pins at outer circle have pin functions of line output transformer for color TVs,then weld outer circle pins of this Color TV line to original machine,so as to realize replacement of original Color TV line.
Caution:prior to installation of all-purpose Color TV line,please make sure to unplug Video amplifiler board of original machine.After installation of all-purpose Color TV line,please test filament voltage,video amplifier voltage and voltage of acceleration node to be normal,and install TV amplifer's board later,or it can easily damage the kinescope.
Ⅲ、Application Examples
When applying all-purpose color TV line output transformer,it is imperative to verify function of each pin,pin sequence marking for line output transformer of each color TV vendors,clockwise or counter-clockwise.Therefore,when verifying function of each pin for color TVs,only by looking at drawing of the original machine is not enough.It is necessary to associate actual PCBs to determine the function of each pin.
Next is an explanation of Konka P3486C color TV for instructions:
Figure 3 is a pin function figure for line output transformer of Konica P3486C color TVs After determining function of each pin from output transformer of the original machine,it is viable to connect corresponding internal and external pins of all-purpose Color TV line.Ways are using sections of short lead wire to connect corresponding pins of all purpose Color TV line,see Figure 4,making functions of each pin at outer circle corresondent to function of each pin of Color TV line in original machine.(Note:pin quantily of outer circle for all purpose Color TV line might be different from the pin quantily of Color TV line of original machine.During connection,it is imperative to select the one closest to pin positions of original machine,so as to install all purpose Color TV line on PCB.)After connection of each pin and confirmation of correction,it is viable to insert modified external pins.of all purpose Color TV line to welding hole of each pin from original Color TV line for good welding.(Useless external circle pins can be cut off ).Therefore,connect high and medium voltage,startup for adjustment,and speed up and foucs on the electic voltage.
Ⅳ、Troubleshooting
1、How to make judgment on functions of each pin for Color TV line of original machine without drawing?
when there are no drawings,it is easy to judge power supply pin,line output transistor C machine and grounding pin of Color TV line in original machine.Video amplifier and filament pin are mostly connected to rear board through lead wire,and video amplifier is connected to the rear board after rectifying and wave-filtering,wave-filtering capacitor has a withstand voltage of 250V，therefore，it is easier to find video ampplifiler voltage pin and filament pin.Characteristics of ABL pin is a certain pin of Color TV line's connected to the ground with a 0.047-10uf capacitor,and connect to light PCB with an ABL pin through an electric resistence.+15V,-15V,25V and 45V are mostly power supply for output circuit,when using-14V or -16V of original machine,it is viable to use -15V pin of this Color TV line.Under mormal conditions,postitive and negative 15V are used together for a field output circuit,25V power supplying is a certain field output circuit,so it is effective to make judgment of line change pin voltage which is connected to field output circuit.Pulse pin is normally wired through resistance capacitance and delivered to AFC pin of line scanning module and line pulse input pin of decoding module.Therefore,it is viable to find the pin by analyzing generous functions of each section of clectric circuit of original machine.Of course,if there is a book of replacement material for line output transformer,it would be easier to make judgment on pin functions.
2、What can we do if there is no individual coil from Color TV line of original machine?
Multiple voltage output of all purpose Color TV line is capable of supplying requirements from most color TVs.But individual voltage for a minority of color TVs is not available for all purpose Color TV line.By then,it is viable to use enameled wire or fine flexible cord to circle on magnetic cord of all purpose Color TV line to acquire necessary voltage.But it is worth noted that when adding up the coil,it is imperative to start,from fewer circles to more circles,and add circles while testing the machine.It is forbidden to connect electric circuit for machine testing after adding up too many circles,or original machine can be damaged by high voltage produced by added coil.
To replace double-focus color lines of flat color TV sers,connect the two focusing electrodes of the original television and attach them together to the focusing line of the universal color line.
3、After installation of all purpose Color TV line,what will happen if there is too large or small of row width?
After installing all purpose Color TV line,when row width is too large or small,it is imperative to make adjustments to row width potentiometer,or enter maintence staus to adjust row width data (IC2 control digital loader).it is viable to use larger size correction capacitor or reduce retrace interval capacitor to address the problem.However,maximal changing volume of retrace interval capacitor can not exceed 20% of original capacity,or it is easy to damage line output transistors.When row width is too small,it is viable to use small size correction capacitor or enlarged retrace interval capacitor to solve the problem.
National patent Copyright Reseved
ISO9001 International Quality System Certification Shijiazhuang Huamei Electronics,China
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