Attached Files
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Power.jpg
No Power.jpg
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Why does the KEY line never show up again? I find it here but nowhere else. Refer to schematic pg 46.
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Do you have +12v and +5 volts coming from the power supply? you can check them on IC904 and IC905
If you are not getting any secondary voltages, check that R906 is not open, if it is open IC901 is likely bad, If R906 is ok, I would try replacing C905 & C906
If you trace the Key line on the board from P402 pin 5, it goes to u_COM pin 40 (KB01)Last edited by R_J; 11-15-2024, 05:43 PM.Comment
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Thank you very much for the direction you pointed me in.
I went to check IC904, was seeing 1.3volt on the I pin. Went to check IC905 and when I made the connection with my meter probes to the I pin the CRT powered on completely. Green light, then the light went Amber(standby) after a few seconds as would be expected when powered on and not connected to a VGA signal.
Now
Not in Standby
IC904 :
Pin I = 15.32V
Pin O = 12.14V
IC 905 (Not Standby)
Pin I = 14.6V
Pin O = 4.99V
In Standby
IC904:
Pin I 1.39V
in O 0.06V
IC905:
Pin I = 6.62V
Pin O = 4.99V.
With that said, technically the monitor is power on now. With that said, I had my Negative Probe on my meter touching the chassis when I probed pin I on IC905 and the device powered on. Not sure why it powered on when I did that and I don't want to just say the issues is resolved and have it come back again.Comment
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You could start by checking for poor solder connections around those regulator ic's I suspect over time there may be some poor solder connections, also replace those two electrolytics in the primary, (C905 & C906) there may be other weak caps in the power supply ie: C917, C912 etc.
Post some clear straight on pictures of the trace side of the board, especially the power supply section.Comment
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Thanks. Yeah, thinking maybe a solder joint on IC905, or bad cap that I "tickled" by connecting the voltmeter. Going to touch up the joints incase, and replace C905 and C906 just as a matter of maintenance. Thank you! I love this monitor and have been using it for the past 13 years and hope to get many more out of it.Comment
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Should have also mentioned that before the system powered up by trying to check the input voltage on IC906(no power button press required, just came to life out of nowhere (and I was unable to reproduce this), IC904 had like 0.?V on the input but it wasn't 0V. Afterwards, the Inputs on both show the same voltage as in standby mode. Afterwards I was only able to effect the power on/off state by using the power button.
Also of note, part of the original issue was the power button was not powering on, or off, the device. It was either stuck on, or I had to take the swivel off the bottom, and tap the bottom while plugged in for it to power on after a power loss, which made me feel suspicious of a solder joint, then later when discovered that the fuse was wonky, i blamed that.Comment
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Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.
Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
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Hi all!
I'm trying to troubleshoot a Microsoft Surface Pro (5th gen) model 1796 that won't power on. Motherboard model is M1007506-015. My priority is retrieving data, but the SSD is integrated so it looks like if I can't repair it it'll need to go to a data recovery company. I've done a little basic board repair before, but nothing this advanced until now. So please forgive my ignorance in advance. 😅
I found the boardview for this laptop in the forums here, and am able to open it on my PC with FlexBV.
https://www.badcaps.net/forum/troubl...-hardware-devi... -
Hi all,
TL;DR - this laptop is driving me nuts with the oddball power-related behaviors. Appreciate any insight you can provide!
I'm experiencing a power issue on an Asus Probook P5440UF-XB74. Although I've worked with electronics and computers for decades, this is my first attempt at getting into motherboard-level component troubleshooting. Any help the community can provide is greatly appreciated!
A few weeks ago I was using the laptop (on battery power) for a Zoom meeting. The battery was running very low (long meeting) but I wasn't worried about... -
I have wanting to do this project for quite sometime now and I finally found a switching power supply that will work on this desoldering gun station ZD-915 that the original switching power supply took a shit and just was not worth trying to fix it because this switching power is not quite big enough to handle the heater element and the vacuum pump
One note when I tested the switching power supply and the voltage control board I noticed that this desoldering gun heat up much faster than the original switching power supply which I was really surprised by to the point that I might buy... -
Hi, i was given this lcd monitor last week with the issue of power led blinking. Upon checking the power board, i found 2 pieces electrolytic caps bulged and replaced them.
Later, when i switched on ac power and detected 5v and 15v dc at output pins. But as soon as i pressed on the front power button, the led on power button lights for 1 second and it turns off.
So, i tried disconnect the flex ribbon cable from t con board. But all i got is a white screen with nothing on. I suspect there is something short somewhere that prevent the display being turned on. Can someone with...
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