Panasonic TC - 29 p100r color TV (MD2 movement), scanning adopts frequency doubling method, line of small signal generated by digital box TDA9332HN1 -t. Fault phenomenon for the boot green light, no complete grating, are there any rules flashing bright line, accompanied by the sound of "squeak". For about a minute after the bright line disappear, occasionally heard "creak" sound, green light has been normal.
 
Analysis of maintenance: is there a bright flash, line the main power source with stable 140 v output, measuring line drive pipe QS03 sc2925 (2) c voltage to stabilize the 15 v. Oscilloscope measurement line oscillation output A44 (digital box outlet (5 foot) for stable 31.25 kHz, amplitude is 4.5 the Vp - p; Measuring Q503 c, with the bright line flashing any rules of output waveform, doubt Q503 adverse. Will Q503 welding, measured its b - e Ω extremely positive and reverse resistance is 9.5 k, b and c extremely positive resistance for 4 k Ω, reverse to infinity, black pens and c extremely, red pens and e has infinite resistance when extremely, reverse connection of 17 k Ω, determine Q503 has damaged. In 2 sc2925 sc458 instead of 2, in the condition of no signal boot appear normal blue grating and characters.
 
 
 
 
 
 
 
 
 
Then there was a strange failures: normal grating in about a minute later, screen the most began to appear on the right, and the black side constantly expanding to the left. For fear of line output part flow phenomenon, so turn it off immediately. Will pick in the main power supply current limiting resistor R855 voltmeter (2.2 Ω) ends after boot observation, normal blue grating for stable 1.5 V voltage, with the emergence of black border and expands unceasingly, voltage decreases gradually, show no flow phenomenon, can be bold to look at the boot. As the growth of the time, black side became the width is 6 cm and neat vertical black belt on both sides continue to move to the left. Black side after about three minutes, black belt fixed in position no longer mobile as shown in figure 1. From start to black belt stop moving this time, no change character.
 
A black belt in fault repeatedly checked also didn't rule out a few days. Then in a short period of time on the increase and the growth of the boot time, the number of grating fault changed again, sometimes a boot appears as shown in figure 2 and figure 3 grating, sometimes no grating, only "squeak" sound.
 
Calm down and find relevant information, see "appliance repair" on page 14, 2006 after big inspired He Chenfan comrades. So use oscilloscope measurement TPD14 point line circuit (see figure 4) feedback voltage waveform, just boot for Vp - 11 p, then gradually reduced, Vp - 6.5 p black side, on the right side of the screen appear when the waveform amplitude stability, but the black border to continue to move to the left. Shutdown, check C518, found that has black, touch the feeling is very hot. When turned on, wait for failure occurs with alcohol cotton ball to cool C518, waveform amplitude with increasing for the cooling, black belt also gradually disappear, waveform of up to 20 vp - p, which indicates that the temperature characteristic of C518 has seriously deteriorate. Welding C518, measurement with multimeter 10 k it's open, for s10pF with capacitance meter measuring the capacitance (normal should be 1000 m3). With a volume compared to the original capacitance several times SMIPF23 (pf / 2 1000 kv) after substitution, measuring TPD14 point line feedback voltage waveform is stable 20 vp - p, troubleshooting.
 
 
In addition, in the maintenance has accumulated the following data:
 
Line drive pipe 2 sc2925 2 sc458 substitution is available, also can use 2 scl926 substitution. Line drive transformer primary resistance is 0.8 Ω, secondary 0.1 Ω. Line drive transformer under no-load condition (disconnect D512 and R522), measuring Q503 c of waveform of 31.25 kHz and vp - p, transformer secondary to 2 vp - p. Microprocessor IC1101 crystal 62, 63 feet receive X1101 model is 13400 a7i (whether for 4 mz crystal), with normal 3.58 MHz and 4.00 MHz, 4.43 MHz and 6.00 MHz substitution, television can work normally. Don't pick up the crystal, boot green light grating, cannot undertake various operations. TV work, on both ends of X1101 measuring less than standard sine signal, just some very low noise amplitude.