Screen comes on,with many coloured lines,and after some time clicks on to good pcture.
Have checked boards for dry joints,and inspected electrolytics for bulging.
Thinking it might be a lazy crystal.
Can you suggest anything to try.
once picture appears it stays ok all day.
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First of all, thank you for posting your question here at Fixya. Random subsequent turned off and on like what you've described is mostly caused by the following. 1. Excessive heat - if the unit turned off and on randomly after a few hours of being power on, then high chance that the parts gone to heat build up that trigger the thermal protection circuitry to kick on. If this is the case, I would advice you to give the unit's vent a proper ventilation, keep away all the obstruction to have a sufficient air flow. 2. Bad solder joints - cracked, dried, cold solder is one of the common caused of the symptoms you've mentioned. I would advice you to check the power supply board for bad solder joints, it is hard to spot, I would advice you to work on the brightest area or used portable lamp and magnifying glass, re-solder all suspected joints. 3. Power supply malfunction - Once the power supply board gone to overload, out-of-regulation condition, the feedback circuitry will sensed it and will caused for randomly shuts down. I would advice you to check the power supply board's electrolytic filter capacitor. Partially faulty (leaky,dried) electrolytic capacitor can produce out-of-regulation condition on the power supply. Most of the faulty electrolytic capacitor has a physical indication of fault like bulged/dome at the top and can be easily identify through visual inspection. If your unit is not under warranty period, inspect it from the power supply board. See sample picture of bad capacitor with dome at the top.
Electrolytic capacitor info.
If you've confirmed that excessive heat, bad solder joints, electrolytic capacitor are isolated and not the issue, I would advice you to replaced the entire power supply board (part number : 75014421). I saw it in stock at this link :
Hope I helped you. Have a great day! Rating and feedback are highly appreciated!
First of all thank you for posting your question here at Fixya.
The symptoms you've described is a consistent power supply issue. It is caused by faulty(leaky/dried) electrolytic capacitor on the power supply board. In the first stage of the symptoms, warm-up will make itself stable that's why you need to unplug it a few times, turned the power button key several times before it will come on but the symptoms will get worst as time goes by, time will come that the unit will take more time to come on and/or will not even power up at all. You've mentioned also that sometimes you have to shake the unit then it will power up fine, then high chance that there's a bad solder joints (cold, cracked, dried) solder on that board.
If your unit is not under warranty period (if so, avail it because the manufacturer will fix it for free), take off the rear cover, pull-out the power supply board, this board is where the power cord's directly connected. Check first for bad solder joints, it is hard to spot, you must work in the brightest area or used portable lamp/table lamp. Re-solder all suspected bad solder joints.
Look for leaky electrolytic capacitor, most of the time it has a physical indication of fault like bulged/dome at the top and can be easily identify through visual inspection. See sample picture below.
This kind of symptoms encountered not only on DLP TV but in all type of TV like plasma, LCD, and CRT. Watch the video below.
The technical part is, if the capacitor is not leaky (dried/no bulged, dome at the top and looks like fine), you must have a capacitor checker to determine its condition. If not available, you may replace all electrolytic capacitor on the output of the power supply board, it will not cost you much because it is one of the cheapest part on that board, cost only less than a dollar and widely available at electronics supply and online. Watch the video below for more info regarding electrolytic capacitor.
Your problem is caused by dry joints and cold solder on the board. If you have a soldering iron and soldering lead open the back panel of your tv. Look for dry joints around the board especially on the power supply section.Cold solder is hard to spot, it is necessary that your working area have sufficient source of light or you may use a table lamp.
Hope it may help you.
Have a nice day!
Thanks for using Fixya.
Hi, White line across the screen indicates that tv got vertical deflection failure problem that may be due to vertical output chip failure. If that kind of problem occurred, tv select protection mode and red light starts blinking 4 times. Please check vertical output chip in tv main board and replace it to solve tv issue. This job needs soldering work so local tv repair shop will help you. Thanks.
It is an indication that you have a problem on the vertical section on the main board.
The faulty parts is the electrolytic capacitor which affect the linearity of the screen that's why you encountered that kind of problem.
I've advice you to send it to repair shop or look for a qualified technician to isolate the faulty electrolytic capacitor and do re-soldering for some dry joints on the main board.Once replaced the capacitor your unit will back to normal again.
thanks for using fixya...
Most likely the Y sustain board is bad. I always replace the Y drives also as they can destroy the new Y board. The Y is the board on the left hand side and connects to the Y drive boards. I was going to say, send me a picture of the problem but you said now it is dead.
Hi Shailendrar , your problem sounds like vertical collapse , the whole picture has collapsed into a thin , very bright centre line ? maybe the result of dry solder joints , does banging on the side of the tv temporarily fix ? if so , the circuit board requires inspection for bad solder joints . Alternately the vertical chip/transistor may be blown , replace as required. Cheers T