Re: HP LP3065 with partially failed PSU (USB works)
At the moment i am a bit stuck and still trying to figure out what that 6-legged thing is (see above). Most likely name is "IAL BH". Does anybody have an idea?
beejay
Member
Last Activity: 02-03-2015, 02:13 PM
Joined: 01-17-2015
Location: Stuttgart
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Re: Dell 3007WFP and PA-4151-1-LF Help!!
I agree with budm. Those housings usually break on their sides where they border with the metal backplate. The way this looks it should have been audible and smelly at the time of failure.
You may want to unsolder that FET and get a new one. However there is a chance something else on the board has caused the FET to fail. So if you don't want to investigate further and just exchange that FET, get yourself 2 or 3 of those as replacements. Otherwise you will pay twice the shipping when you blow up the replacement...Leave a comment:
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Re: HP LP3065 with partially failed PSU (USB works)
I traced the signal "PWR_ON" through the control board and it only passes 2 serial resistors and ends up at one of the microcontroller (NT68F63LG) pins at which it is down to 0.06V from 0.3V. On the TFT board it directly connects to a pin of some unknown 6 leg IC. (see closeup middle picture) It took 20min to get a good shot and i guess it sais "IAL BH". But even with the name i cant identify this thing. The black spot on the closeup is the "PWR_ON". It connects to the IC as well as via 1kOhms to +3.3V....Leave a comment:
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Re: HP LP3065 with partially failed PSU (USB works)
Now i found something interesting. In the picture below you can see the naming of the lines that go to the TFT-board. Among 4 times 18V there is one labeled [B]PWR_ON[/B] and it cycles from 0V to 0.3V in that well known rythm. (by the way PS_ON is not connected by the cabling) Those 0.3V don't make any sense, do they?
What is this signal? Is PWR_ON the TFT board telling the control board that the power is good?Re: HP LP3065 with partially failed PSU (USB works)
Now i found something interesting. In...Leave a comment:
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Re: HP LP3065 with partially failed PSU (USB works)
Somewhat good news (i guess). I tested the PSU alone today and it seems fine. Which could mean that the control board is at fault.
Here is what i did:
* Take the PSU board out and disconnect everything else.
* Connect 1kOhms from 5V to the STBN-24 which switches on the PSU permanently.
* Reconnect only the controll board (because the PSU needs some load on its 5V to work correctly)
* Supply 230VAC and see what happens.
-> The PSU is still cycling on-off-on-off ... i check...Last edited by beejay; 01-31-2015, 07:25 AM.Leave a comment:
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Re: HP LP3065 with partially failed PSU (USB works)
Sorry, i almost forgot. No it does not. I think the inverter is not being switched on before the control board decides that the main power looks good....Leave a comment:
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Re: HP LP3065 with partially failed PSU (USB works)
I tested for the issue described by Electronomo here: [url]https://www.badcaps.net/forum/showthread.php?t=37891&highlight=lp3065[/url]
He reported an open resistor in a divider branch of the L6561 ([url]https://cdn.badcaps-static.com/pdfs/7becffd2cd8a3b7bb041e51b92f46e24.pdf[/url]). Turns out there is even an example application of the IC in the datasheet that closely matches the PSU in our monitor. (see Figure 7 on page 6) Or at least the divider is exactly the same.
There are 3x serial 620kOhms....Leave a comment:
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Re: HP LP3065 with partially failed PSU (USB works)
Now on to the [B]main&standby power supply[/B].
From left to right:
1) Overview of the whole board
2) control board side
3) inverter board side
4) closeup of the lower hot section with power-line connector
5) closeup of the upper hot section
For completeness here are links to the images of the backside (thanks freddyfena)
[url]https://www.badcaps.net/forum/attachment.php?attachmentid=23551&d=1299451316[/url]
[url]https://www.badcaps.net/forum/attachme...Last edited by beejay; 01-29-2015, 02:58 PM.Leave a comment:
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Re: HP LP3065 with partially failed PSU (USB works)
I am back. It has been a busy week (and still is). So forgive me for taking a while.
Pictures of the main PSU will follow. Though they should be identical to these boards: [url]https://www.badcaps.net/forum/showthread.php?t=13640[/url]
Here are some pictures of the [B]backlight inverter[/B].
From left to right:
1) location of backlight inverter board and its high voltage cabling
2) overview shot of the lower half of the board including the connector to the PSU at the top of the image...Last edited by beejay; 01-29-2015, 12:45 PM.Leave a comment:
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Re: HP LP3065 with partially failed PSU (USB works)
I looked around ZD101 a bit and the reason for MrYfe readings ("shorted") is a parallel resistor of 0.16 Ohms to ZD101. When taking the resistor out the gate of the mosfet (20N60C3) is open and the T-E legs show 0.46V in one direction and open in the other, which does not look bad to me.
Since this is a forum with caps in the title and the top of that large 180uF was not indented as the others i took it out and checked. It shows 158uF on my DMM which is a ~10% loss. Should i try to fix that...Last edited by beejay; 01-24-2015, 03:49 AM.Leave a comment:
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Re: HP LP3065 with partially failed PSU (USB works)
Hello, i am a radio amateur and as such an electronic enthusiast by nature.
I am now coming back to this forum for about half a year and finally i found some time to start fixing my monitor. Hopefully i can figure this out.
As it happens i ended up with just the same monitor as above which shows a somewhat similar behaviour. The control board tries switching on the main power supply again and again. However when I checked the output voltages, they all show up as far as i can tell. The 18V on the control...Leave a comment:
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