Re: LG 50PA4500 Plasma Troubleshooting
Thanks for your time on this, I really appreciate it. I thought I would list the component labels identified in case it further helps others dealing with a similar issue. I found only found two failed components.
Optocouplers (as arranged: left to right, top to bottom):
IC402, IC481, IC401, IC501, IC552, IC553, IC441, IC442
Resistors (27 Ohm):
R420, R417, R485, R482, R413, R415, R416, R414, R449, R448, R453, R452.
Resistors (15 Ohm):
R490, R489, R572.
Resistors (330 Ohm):...
brassicGamer
Member
Last Activity: 02-02-2023, 09:53 AM
Joined: 01-12-2020
Location: Sussex
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Re: LG 50PA4500 Plasma Troubleshooting
Well, it made no zero difference to the symptoms (some snow when it first powers on, then nothing), so the problem must be further back. On the verge of giving up on this but I've put a lot of effort in so far cleaning it up (from the smoking tar). Would be nice if I should just swap in working boards to find out which one is the problem.Leave a comment:
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Re: LG 50PA4500 Plasma Troubleshooting
It's cool, they're literally the same length. Lucky, I know, but thanks for the heads-up.
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Re: LG 50PA4500 Plasma Troubleshooting
Okay, okay. I got lucky and someone was throwing away a Panasonic Viera panel literally as I was driving past them. It had two RJP30Ks in it, which look like a good match:
Model___Voltage_Amps_Pulsed_Package
30F126__330V___30A__200A__TO-220
RJP30K__360V___40A__300A__TO-220Leave a comment:
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Re: LG 50PA4500 Plasma Troubleshooting
Seems like a good place to ask such a question!...Leave a comment:
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Re: LG 50PA4500 Plasma Troubleshooting
I found some 30J121s on Mouser, which are same spec but rated for 600V instead of 300V, so hopefully they will do the job....Leave a comment:
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Re: LG 50PA4500 Plasma Troubleshooting
I found another one and they're actually IGBTs. First time working on a plasma panel so I've not come across these before. Ordered some as I don't have any in stock. They were in series with failed capacitors so I guess they got slammed by unfiltered current over a long period of time until they failed. I'm hoping that replacing these fixes the problem.Leave a comment:
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Re: LG 50PA4500 Plasma Troubleshooting
I removed the heatsink nearest the driver board and tested all the MOSFETs and Schottkeys. One of the MOSFETS is bad. I guess I should also test all the others just to make sure.Leave a comment:
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Re: Sony Bravia KDL-60W855B
The actual final note is that I purchased a new power board and that fixed the problem. Go figure.Leave a comment:
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LG 50PA4500 Plasma Troubleshooting
Hi folks. This panel seems to be a 'favourite' on these forums. I've checked through all the existing posts and my issue doesn't match up with the common faults described. I think it might be the logic board.
I acquired it second-hand recently and the previous owner described the panel working fine until a power cut, when it only turned back on briefly. The apparent issue was that, when powered on, the TV would display the manufacturer logo and then go into standby mode. I figured this was the main board shutting it down after a test condition failed.
I checked the... -
Re: Specific Caps Keeps Venting
Wow. Thank you. I checked old photos and can confirm the markings are the problem. I hope more damage hasn't been caused. I double-checked and it's definitely 16V btw....Leave a comment:
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Specific Caps Keeps Venting
Hi all. So I've got this neat motherboard. It's an HP version of the Asus TR-DLS, included in the tc3100 server. It was working perfectly fine last time I used it, which was about 4 years ago. It has been in dry storage since and was in perfect cosmetic condition...
...except: three of the large caps near the CPU had randomly fallen out. This was due to weak solder joints as I was able to remove another one with very little force. After redoing all the joints for the related caps (competently - no shorts, etc.) and powering up the board, it ran for 2 seconds before one of the caps... -
Re: Sony Bravia KDL-60W855B
Just wanted to add a final note to this, because I got the same error again after moving the set (it will soon be mounted on the wall). It seems quite a specific problem, but I hope it might be able to help someone else.
It's definitely to do with the backlight system because this time I was able to verify that there is picture (using the torch method) and there is audio. I use the following procedure to fix the error although it does unfortunately mean removing the rear panel:
- Power off unit.
- Unplug from mains....Leave a comment:
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Re: Sony Bravia KDL-60W855B
Might wait until I get my hot air rework station rather than risk the soldering iron...
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Re: Sony Bravia KDL-60W855B
Well now I don't know what to say. While testing earlier to see if there was sound, the TV went into protection mode and flashed red 4 times, which means 'bad panel'. This immediately made me suspicious because that's two completely different problems even though no changes have been made.
So I persisted. Following your advice I removed all boards, inspected for cracked / dry solder joints or debris / corrosion, cleaned all connectors and plugs, reseated everything and tried again. The error had cleared, but still no backlight...Leave a comment:
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Re: Sony Bravia KDL-60W855B
One more question. If the screen isn't working, how am I to initiate and monitor a firmware update? I've downloaded it onto the USB stick, plugged it into to a socket on the TV and turned it on. According to the service manual it will automatically update, but I don't know if it's actually doing that or not.Leave a comment:
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Re: Sony Bravia KDL-60W855B
I saw that mentioned in the service manual actually - might give it a shot, thanks....Leave a comment:
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Re: Sony Bravia KDL-60W855B
Yes, as we don't have a router at the moment. It did momentarily work fine post-update after reinstalling the caps....Leave a comment:
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Sony Bravia KDL-60W855B
Hi folks.
So this thing has been in storage for a while and I got it back home yesterday. Amazingly it turned on with no problems... until I opted to install the latest software. The download went fine, then the update process began (a spinning arrow) and it appeared to complete because the picture came back. Then it powered down, flashed red three times in a loop, and wouldn't turn back on again. Attempting to power up resulted in a couple of relay clicks and that's it.
Following the service manual, it indicated that I had a bad main board. I figured this might have... -
Re: RM1000 PSU Not Quite Dead, Not Quite Alive
Thanks for the guidance - I'll plug it in to a mobo. I did have a 12V fan attached for load, but maybe that wasn't pulling enough.Leave a comment:
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