Re: LG 50PS30 Z-sustain questions
Update:
Three of the GT45F122 IGBT's on the HV side of the board were short as well. So all up, that's 5 devices that shorted. Can anyone suggest a replacement for these? I can't seem to source them from reputable suppliers and am loathe to get them off of ebay. One alternative seems to be the Fairchild FGPF4633, I'm trying to locate some in Australia.
Thanks all, hoping I don't find anything else blown up once I get these repaired.
Cheers,
ks
kingsapper
Member
Last Activity: 11-29-2013, 11:44 PM
Joined: 10-24-2013
Location: Adelaide, SA
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Re: How to Troubleshoot a Plasma TV (p50s602) with an Oscilloscope
Yeah, important safety tip: When this system is operating there may be FLOATING parts of the system. Not directly connected to safety earth, the heatsinks or other parts of the system may float through capacitive coupling to a high frequency (ie a switching waveform) signal up to who knows what. This is not detrimental to the system, but if you happen to form a path to ground for it, that energy would like to flow from high potential to low potential.. so don't be that link!
tom66 is...Leave a comment:
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Re: How to Troubleshoot a Plasma TV (p50s602) with an Oscilloscope
Test points are handy, but if you can get a service/training manual for the boards you don't neccisarily need them if you can back-pin or solder on a takeoff point of your own.
When it comes to using a scope there are a few basic things to consider..
1. SAFETY: you're going to be poking around in a running plasma TV. I think we all know what that means.
Don't work alone, and think about what you're doing before you do it.
2. Think about what you're going to...Leave a comment:
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Re: LG 50PS30 Z-sustain questions
Update:
Both of the STF20NF20 NMOSFETs appear to have gone short-circuit. Spare parts have already been ordered, we'll see how things go. Oddly enough the FDP51N25 seems to be fine. I may replace it with a new part just in case it "took a hit". Don't want it to die and take everything else out with it.Leave a comment:
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Re: bad power very VERY bad power! dont want server damage
All the more reason to run a real file system like ZFS
Enterprise power supplies in real servers are built pretty hard-core. And most modern servers have dual redundant power supplies that are hot swappable by staff in the dork fridge (datacenter, oops.. )
If you're not running "real" servers but desktop machines configured as servers it's not a bad idea to consider setting up battery busses of 12 and 5v, and then park the chargers/high current power supply on the batteries. If...Leave a comment:
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Re: LG 50PS30 Z-sustain questions
I'm doing failure analysis on the three MOSFETs listed on the repair kit you guys put up over the weekend. That will give me the failure mode, which will send me in the right direction hopefully. It would be nice if it was as easy as a freewheeling diode with a snubber network or something.. I'll post whatever I find.
Cheers,
KSLeave a comment:
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Re: LG 50PS30 Z-sustain questions
Panel model is PDP50H30001
Good news about the document being more in depth. Maybe it's just the tech in me, but if something breaks I want to know why it broke and prevent it from happening again. That's the difference between fixed and repaired.. I can whack a couple of FETs in but it's not fixed until the underlying condition that blew the FETs is addressed.
Thanks all
KSLeave a comment:
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Re: How to sweep test an IF filter
doesn't appear that the source and load impedances are matched.. what's the working impedance of that filter?Leave a comment:
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Re: warning!xcelite flush cutters!
In my opinion...
Cutters (Diagonal, flush, etc) should be sharp and well cared for. If you use them improperly they will damage things of course, but if you use dull banged up cutters or try and cut large or too-hard material (piano wire) with your cutters you will wreck things. So don't do that.
Likewise with fine-jaw pliers and tweezers. Very handy when you're using them correctly, but if they get banged up they're worse than useless.
Cutters [U]should[/U] be sharp. Soldering irons should be hot....Leave a comment:
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Re: LG 50PS30 Z-sustain questions
I have the service manual for the 50PS30 which does not mention the Z-sus at all really.. I was expecting more out of a "service manual" it was actually a bit disappointing. Thanks for the point to the other manual, I may take a look and see if there's any more in that. Thanks for the lead.
Cheers
KSLeave a comment:
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Re: LG 50PS30 Z-sustain questions
Ok, that being said I just took a closer look at the datasheets on those two MOSFETS.. if this is a well known issue does anyone know [U]why[/U] these parts blow up? The manufacturers are reputable, so I'm thinking that there's a design flaw in here. Has anyone published a hack/improvement to prevent it from happening again?
Cheers,
KSRe: LG 50PS30 Z-sustain questions
Ok, that being said I just took a closer look at the datasheets on those two MOSFETS.. if this is a well known issue does anyone know [U]why[/U]Leave a comment:
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Re: LG 50PS30 Z-sustain questions
Much appreciated for the assistance. I've got a developer's account at a few places so I'll look into the parts and order replacements. I've gotten quotes in the neighborhood of that ebay price for a whole new board!
Thanks again.
KSLeave a comment:
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LG 50PS30 Z-sustain questions
Hi All,
I have a LG 50PS30 in near-mint condition given to me by a colleague in it's original packaging (!). On startup it was black screen, but the LED indicator blinked red then went solid blue. I took it apart and consulted the service manual and found the Va and Vs rails were 200mV or so.
After looking around at troubleshooting tips (I'm new to TV's, all my experience is on communications systems and robotics/mechatronics) I disconnected the Z-Sustain board and fired it up. Picture was dim and discolored (a known side-effect of no sustain, I see) but the rest... -
Re: New Members - please post your introductions here
Hi All,
I'm a qualified Electronics and Communications Systems Technician with many years of tinkering before getting a qualification.. Background in communications systems and microcontrollers/PCB design.
Finishing another degree in sciences. I have quite a bit of experience making and repairing things both in a cleanroom environment and in the "MacGuyver" environment.
Look forward to contributing where I can.Leave a comment:
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