 Posted: Tue Jul 22, 2014 12:01 pm Post subject: |
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| I have Onida color Television (ONIDA BLACK), IC TDA 8841 , ST 92195c
Problem: Vertical Folding I have replaced the LOT due to LOT ARC and vertical IC TDA 8357 After replacing LOT , i found that there was a shot in the circuit Location : D404 diode shot Can some one tell wat is the diode value??? so that it will be use full for me to replace Please help me out I could not able to find the circuit diagram. |
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| Posted: Thu Jun 11, 2009 4:40 pm Post subject: Re: ONIDA color tv regrading- set dead and no audio also |
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| pls check memory ic and +12 volt switching transistor(eg.A966) | |
| Posted: Mon May 18, 2009 7:48 am Post subject: |
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| Check with a scope if the drive signal to the horizontal output has the correct frequency. If the capacitor that defines the horizontal frequency goes open circuit (very common with some types of polystyrene capacitors that were used by Daewoo and others), then the horizontal oscillator will run at about 0,5-1 MHz instead of 16 kHz and of course neither the drive nor the output stage will operate correctly at a so high frequency. | |
| Posted: Mon May 18, 2009 7:14 am Post subject: ONIDA color tv regrading- set dead and no audio also |
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| I have a ONIDA color television model is 21 PFDB3, in its main board its return that GL-21, which has MICOM ST 92195, chroma ic TDA 8841, POWER SUPPLY IC is STR F 6654, Vertical ic is TDA 8357 JS, horizontal output transistor 2SD 1878 and audio is TDA 2616.
Problem: TV is fully dead, Power supply is ok, Initially Power supply generating B+ is 95V, and 11V, 25 V for audio , 33 V for Tuner. +5V for MICOM (st 92195) is present. When i tried to switch it on through remote/ front panet key combination it is not coming out of standby mode. Satand by pin is always low, when i touched the reset pin (+5V) through mutimeter probe, the standby pin become high (but voltage at that pin was arround 2V only), then the 8V supply and +5v supply switched on , also B+ voltage raised to +115V. All the voltages gernerated by power supply is seems to be okey , not loaded. No EHT is being generated, i checked voltage at collctor of HOT (2SD1878) it is 115V, i checked horizontal driver stage , driver transformer is ok, driver transister is ok, voltage given to horizontal driver satge through resister is getting droped from 11v to 9V , driver transister is getting hot . I checked the TDA 8841 ic ,+8V power supply is present, H out pin is giving arround 0.6 volt. i checked EHT transformer it is primary windings are ok, the power supply is not loaded but there is no eht generation, i could not understand where is the problem is... because of this no voltage to heter and vertical stage... There is a green LED conected to processor (St 92195) ic next to its STANDBY pin, this is switched on when i touch the RESET pin using multimetr probe and glowing contineously, but this is not correct because when the TV was working perfectly allright it was always off (green LED). whenever i switch on the MUSIC mode in this TV (ie.. switching of video only audio was section will work ) at that time it use to blink, whent i use to set alarms that time it use to becontineously on. So how to find the MICOM ic (ST 92195) is ok or faulty. please help me out... I could not able to find the circuit diagram .. Some one said to me ONIDA circuits are made by JVC |
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