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Sraros started a topic HP Elitedisplay E231

in Troubleshooting Computer Displays

11-19-2024, 01:17 PM
HP Elitedisplay E231

Hello,

I have this HP monitor which flickers for 15 seconds approximately when it cold starts (when power cable gets connected). After these 15 seconds the monitor works just fine.
Also when it comes up from sleep mode also works fine.
the PSU and mainboard are fine because I tried swapping with good boards and it also does this. I am not looking to repair it, just as general knowledge what it might be....

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Sraros replied to dynabook Satellite Pro c50-h-W10 power issue

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-12-2024, 05:43 PM
Finally found the short at U22 QFN reading ALTM689.
I ordered the part as NB679 as I found it from another post here. So waiting for it and hopefully it comes back to life…

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Sraros replied to dynabook Satellite Pro c50-h-W10 power issue

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-10-2024, 10:54 AM
Some additional information that may help
L9 is the 5V rail
L8 the 3.3 rail
PL1 the battery charging rail, 8V
on PQ5 I have 19V coming from the right side

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Sraros replied to dynabook Satellite Pro c50-h-W10 power issue

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-10-2024, 05:47 AM
I want to give another shot on this laptop.

Here are some more information:
TC1, TC11, TC14, TC13, TC16, TC17 are all shorted rails. 0Ω) i lifted them 1 by 1 and they all test fine out of circuit.

Then removed some components like in photo attached but still have the same result.
After L9 removal at least the short to ground disappears on the left pin....

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Last edited by Sraros; 11-10-2024, 05:50 AM. Reason: Wrong photo attached
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Sraros replied to DELL P2217H power issue

in Troubleshooting Computer Displays

10-15-2024, 01:21 AM
Thank you for the suggestions. I think your message came right on the same time when I removed the shorted cap.
So, after removing the shorted cap. The mainboard worked as I said previously by swapping it to a similar Dell monitor.

Then regarding the LEDs: I changed the BL managing chip with another one I had available, MP3375. This chip needs at R864 a 0 Ohm resistor and now the monitor works just fine!...

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Sraros replied to DELL P2217H power issue

in Troubleshooting Computer Displays

10-14-2024, 04:25 AM
Update
I removed the caps to elimilate at least this one and found a short cap pointed with the red arrow.
Now the screen powers on, I have the Dell logo for half a second displayed but then the LEDS shut off. I still have power on the monitor though and I can switch on and off the monitor....

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Sraros started a topic DELL P2217H power issue

in Troubleshooting Computer Displays

10-14-2024, 03:47 AM
DELL P2217H power issue

Hello,
I have two identical Dell monitors P2217H that don't power on. I took the PSU and mainboards out and connected them on another monitor. Connecting just the PSUs on the third monitor (with similar mainboard) and the monitor worked fine. So both have an issue on the mainboards.
It seems the 19V rails on both mainboards have a short. Pins 5-6 are the 19V rail, 3-4 is ground, 1-2 is DIM and PWN_ON/OFF
I circled the caps in green where the short appears. It would be helpful if someone can indicate a suspect or a way to figure it out....

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Sraros replied to DELL Inspiron 3477 AIO

in Troubleshooting Desktop Motherboards, Graphics Cards, and PC Peripherals

06-18-2024, 04:54 AM
Hello again, eventually it was that simple indeed.
With the original charger the computer works just fine.
65W charger is enough. Thank you!

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Sraros replied to DELL Inspiron 3477 AIO

in Troubleshooting Desktop Motherboards, Graphics Cards, and PC Peripherals

06-05-2024, 02:39 AM
I will check with local sellers if I can test before I buy

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Sraros replied to DELL Inspiron 3477 AIO

in Troubleshooting Desktop Motherboards, Graphics Cards, and PC Peripherals

06-04-2024, 12:00 PM
Thanks for the prompt reply.
Here's a photo of the logic board. I checked on the other side as well but there's nothing written.
I come back with the rest to check...

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Sraros started a topic DELL Inspiron 3477 AIO

in Troubleshooting Desktop Motherboards, Graphics Cards, and PC Peripherals

06-04-2024, 10:52 AM
DELL Inspiron 3477 AIO

Hello,
I post this in this section for a Dell Inspiron 3477 All in one as the motherboard is more close to a laptop one.
So, the issue is that whatever adapter I use, I get this screen when it starts up. I tried aftermarket adapters and original HP adapters, both 65W and 90W. Minimum requirement is 65W.
I don't have its authentic Dell adapter as I took it for free in case I manage to repair it, but the HP ones I think are pretty much identical.

First thing I checked is if the dc jack on the board has an issue but with the MM I see all three pins, ground, 19.5V and...

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Sraros replied to 17PW15-8 blows fuses after lightning

in Troubleshooting TVs and Video Sources

12-10-2023, 07:23 AM
Sorry guys, I rushed a little bit too fast. It was the bridge rectifier afterall... I missed checking between + and 2nd leg. So problem solved.
Still thanks for the answers

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Sraros started a topic 17PW15-8 blows fuses after lightning

in Troubleshooting TVs and Video Sources

12-04-2023, 01:26 AM
17PW15-8 blows fuses after lightning

Hello,
I picked this PSU 17PW15-8 from a friend's TV with a burnt fuse, after some days of rain and lightning strikes. The TV was on standby when it happened.
With new fuses it burns them as well. I checked bridge rectifier, all the TO220 components, diodes and basic caps, replaced IC806 SMPS, and FETS driving the big transformer. I also isolated the secondary circuit by cutting the rails of the FETs to the primary coils. I don't know even know if that makes sense, but I did in hopes to isolate the problem.
Any ideas what to look for?...

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Last edited by Sraros; 12-04-2023, 01:41 AM.
Sraros replied to Dell U2413 turning off

in Troubleshooting Computer Displays

10-07-2023, 02:23 PM
Re: Dell U2413 turning off

2years later one more monitor U2413F with the same issue.
Only this time the monitor only had standby voltage straight from the power on state instead of shutting down after a while.
These spare BT169D came in handy

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Sraros replied to dynabook Satellite Pro c50-h-W10 power issue

in Troubleshooting Laptops, Tablets, and Mobile Devices

06-01-2023, 12:44 PM
Re: dynabook Satellite Pro c50-h-W10 power issue

Not to underestimate any of you but as I am left with split advice, I am a little in doubt here.
Is it safe afterall to inject a 1V power into that rail?
Are these readings I posted enough to say there’s a short to ground or is it normal?

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Sraros replied to dynabook Satellite Pro c50-h-W10 power issue

in Troubleshooting Laptops, Tablets, and Mobile Devices

05-30-2023, 12:24 PM
Re: dynabook Satellite Pro c50-h-W10 power issue

Erm, all the tests were without the battery connected…

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Sraros replied to dynabook Satellite Pro c50-h-W10 power issue

in Troubleshooting Laptops, Tablets, and Mobile Devices

05-30-2023, 05:06 AM
Re: dynabook Satellite Pro c50-h-W10 power issue

I am writing again in better english, hopefully
Anywhere I measured in this rail, I had 1 Ohm resistance to ground. As some time passed the resistance measurements were dropping up to 0,6 Ohm

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Sraros replied to dynabook Satellite Pro c50-h-W10 power issue

in Troubleshooting Laptops, Tablets, and Mobile Devices

05-30-2023, 12:58 AM
Re: dynabook Satellite Pro c50-h-W10 power issue

Positive or negative started with 1 Ohm and after checking over some more, dropped to 0,6 Ohm

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Last edited by Sraros; 05-30-2023, 01:11 AM.
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Sraros replied to dynabook Satellite Pro c50-h-W10 power issue

in Troubleshooting Laptops, Tablets, and Mobile Devices

05-29-2023, 06:21 PM
Re: dynabook Satellite Pro c50-h-W10 power issue

Thank you for the info.
As I don’t have a proper bemch power supply, would a DC-DC stepdown converter with output 1V constant and max current 4.5A be able to inject to find the short?

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Sraros started a topic dynabook Satellite Pro c50-h-W10 power issue

in Troubleshooting Laptops, Tablets, and Mobile Devices

05-29-2023, 04:49 PM
dynabook Satellite Pro c50-h-W10 power issue

Hello,

I have this laptop that is not charging at all.
Removing the MB I first noticed the PET film insulator at the back is thermal shrinked seemingly coming from the battery circuit and heavily distorted behind the 2nd DC-in mosfet Q25 (MDV3604).
The battery itself is drained to 0, with one cell being a little bulgy. I guess the battery died and the circuit tried to push amperes in it?

Anyway with a 19.5V adapter (not original) hooked I have 19V on drain of the 2nd DC-in mosfet.
I have a short to ground on inductor L9, TC17, TC16 and several...

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Last edited by Sraros; 05-29-2023, 04:57 PM.