Hi.
Quick question. Does anyone have a working one of these and could confirm for me the voltage on C819 when the set is running? I have a hunch that there is a problem in the PFC circuit as I am getting 375v here, where I would expect it should be closer to 400v. It's obviously working to some degree, the set does work, but the PSU makes a loud hissing noise when cold and the remote is not responsive until a few minutes after the set has warmed up. I have replaced all electrolytics on the PSU including C819 itself, also the PFC controller (FAN7529). Scoping the outputs shows a...
Clydeuk
Senior Member
Last Activity: 09-20-2019, 07:11 PM
Joined: 01-29-2012
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17PW26-1 PFC output
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Re: Old Techwood (Vestel) with 17PW15 PSU
I should mention this problem of audio cracking off on bright scenes only happens on HDMI it seems, and it's not a fault on the main board as this is the 3rd one it's had (I damaged the original when I first fixed the power supply and didn't screw it down fully, the arc to the frame caused silicon damage). Works fine on SCART apart from the problem with initial power up.
I always struggle with Vestel circuit diagrams. I don't think this is a capacitor problem as I seem to remember replacing the usual bad ones (Chong - Samxxon... -
Re: Old Techwood (Vestel) with 17PW15 PSU
Yes I do have a scope, but not where the TV is (I've taken the set to my folks who I visit from time to time). It might be a few weeks before I get the scope to the set now, but next time I visit I will take the scope and perhaps the other power supply just to compare.Leave a comment:
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Old Techwood (Vestel) with 17PW15 PSU
Hi.
Had this set for ages, never been reliable enough to sell on. Had loads of issues with PSU, most of the common problems associated with caps have been dealt with. Just this last one I thought I might throw here to see if anyone's had it before I delve in deeper. Problem is initial switch on standby ok, press power button blue light goes off but no display, can't put back to standby have to power off completely. Second switch on, comes on but screen is a mess of random lines. Power off again and back on, set comes on fine and works. Only problem then is on bright scenes the audio... -
Re: Samsung PN43D450A2D, screen vertical line, flickering
Best to get the part number off the board itself. It's the small PCB in the lower middle of the screen below the power supply, will have ribbon cables connecting to the Y main (left side looking from the back) and the lower buffer boards, and one connecting to the main board (the one with the inputs on).
It's a guess but it looks like a classic CTRL board type failure.Leave a comment:
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Re: Samsung PN43D450A2D, screen vertical line, flickering
I would guess CTRL board needs replacing.Leave a comment:
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Re: Panasonic Plasma TV TX-P50X50B - Shorted power supply
We serviced a lot of these under warranty from Panasonic from new, the combined power supply/SS design certainly seemed to be an issue from new which during my time at the company never seemed to be resolved by the manufacturer, Obviously as you stated Panasonic regard this as a replaceable assembly and therefore do not offer a schematic, which makes attempts at fault tracing extremely difficult.
In the years I have worked on SMPS I very much doubt your problem has anything to do with anything connected to...Leave a comment:
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Re: Westinghouse 42" HD flat panel question
That looks like a cracked panel to me from the photo, I would steer clear. The damage is probably not visible externally but with the display on it's a dead giveaway.Leave a comment:
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Re: Samsung LN-T3242H works fine for a day, then wont turn on. intermittent.
I think the ic is a 24C32, 24C64 or 24C128, something like that. Not sure about the jumpering, we just used to replace them with blanks which the set then programmed at first power on.Leave a comment:
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Re: Technosonic LCD3201 No Picture
By the way that section in the picture is the audio output stage, which you have established is fine.Leave a comment:
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Re: Technosonic LCD3201 No Picture
That looks like some kind of gluey substance to me. These type of capacitors don't leak like electrolytics do. You really need to test whether the T-CON is getting the 12v supply.Leave a comment:
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Re: Ps-50q96hd That went pop
From previously working in an LG/Samsung service centre the manufacturer considers the Y Main a replaceable assembly and doesn't provide any schematics. For these older plasma sets they even priced the whole PDP including boards (apart from the PS) to be pretty much as cheap as replacing the boards, which for us handling extended warranty repair was always the method used with no risk of another failure. Panasonic did things differently and did have schematics, though board replacement was still the recommended solution. The Panasonic PDP's also came...Leave a comment:
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Re: Technika LCD 32-270 - stuck in standby
If you can be bothered trying to cope with Russian translation monitor.net.ru has a lot of EEPROM dumps, only useful if you have something to program them with though. I doubt you'll find a match but using the board number you may find something close. Obviously no guarantee if you can even find one that it will be any good options wise.Leave a comment:
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Re: RCA (Thomson) F20TF10 in a coma
I'm sensing if the set comes straight on and doesn't respond to standby commands maybe you have a problem with one of the power supply rails, or a faulty microcontroller/eeprom or something like that. I could be totally off here, some CRT sets used a momentary contact in the power switch to switch out of standby as soon as the power button was pressed in. Later sets had a more staged start up controlled by the microprocessor, or sometimes a dedicated micro for the PSU only. Degauss is usually the first thing you get when you push the switch on,...Leave a comment:
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Re: KDL-37XBR6 has no picture but has sound
Since the fuse on the TCON is intact try measuring the voltage at the fuse, usually 12v DC expected here, could be a PS fault, also Sony do use tiny SM fuses on the main boards, possible failure of one of these maybe?Leave a comment:
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Re: KDL-37XBR6 has no picture but has sound
is the screen lit at all, i.e. backlight? if it's an LCD I have seen open fuse on the inverter on a Sony TV with no apparent cause, can you confirm if the backlight is lit?Leave a comment:
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Re: RCA (Thomson) F20TF10 in a coma
yes the crt, line and field sections seem to be working, as is definitely the heater. I can't believe it's been that long since I worked on a real CRT tv that I can no longer suggest the next step, I am convinced I have early stage dementia.Leave a comment:
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Re: 42pfl3606h/12 Phillips tv powersupply/backlight problem
Since you now have no power at all have you checked the fuses? If any have popped you will need to check for a short beyond the fuse before trying a replacement. With the meter on an ohms setting and power applied you will be applying a low resistance across anything you apply the probes to, so the outcome is always likely to be a pop. Always test resistance with the power off.Leave a comment:
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Re: Ps-50q96hd That went pop
Test them out of circuit if you can to confirm. I would also suggest replacing the drive i.c that supplies these if they have failed. Check capacitors in the PSU as well, I expect the PS you got was a pull, and check carefully the PS for dry solder joints, these are notorious for it. You will need a buffer as well or the Y main will fail again straight away, but there is always a danger that you miss something when repairing the Y main and take out the buffer again.
Not a fan of board changing but the general accepted repair on these seems...Leave a comment:
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Re: I've been had
I made same mistake a couple of years ago and paid £70 for a 42 inch LG reported fault screen lights up but no picture. Took a chance on a main or t-con fault, only to discover a cracked screen when I powered up, no mention off the crook of that. Couldn't say much after all it did "light up" still I left bad feedback (he already had a bad feedback which should have triggered alarm bells. Hope the knob reads this forum, I have the exact same set in working order so parts may be useful in future, not worth 70 quid but I may part it out someday if I don't...Leave a comment:
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