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Old 01-12-2018, 10:06 PM   #21
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Default Re: hp f2105 monitor black screen

110miles so about an hour and half

ive been working in sausalito for the last 2 months, but we are off work for now.
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Old 01-12-2018, 11:06 PM   #22
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Default Re: hp f2105 monitor black screen

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Originally Posted by budm View Post
If you disconnect the cable to the inverter board, will you get your power LED back on?
nope, still no light
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Old 01-12-2018, 11:17 PM   #23
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Default Re: hp f2105 monitor black screen

Well, if you come up this way again I can leave the monitor by the front door for you.
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Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956

Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999

Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl

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http://s807.photobucket.com/user/budm/library/

TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809
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Old 01-12-2018, 11:20 PM   #24
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Default Re: hp f2105 monitor black screen

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Well, if you come up this way again I can leave the monitor by the front door for you.
i can drive up that way to get it, anytime.day or night. so whens a good time for you? im fixing this monitor for my parents. they arent liking the temporary monitor i gave them (15") lol
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Old 01-13-2018, 02:13 PM   #25
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Default Re: hp f2105 monitor black screen

Just PM me and let me know when you want to come over and I will give you my address, I am not home that much so I will leave the monitor for you.
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Old 01-13-2018, 02:35 PM   #26
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Default Re: hp f2105 monitor black screen

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Just PM me and let me know when you want to come over and I will give you my address, I am not home that much so I will leave the monitor for you.
ok Thank You i just pm'd you
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Old 01-13-2018, 08:54 PM   #27
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Default Re: hp f2105 monitor black screen

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If you disconnect the cable to the inverter board, will you get your power LED back on?

If you wouldnt mind lending some assistance, id still like to try and troubleshoot this one, mainly for the learning experience. im technically inclined, i have a DMM and a basic understanding of electronics/electrical. im in no hurrry to fix this, so it would be at your leisure if not i totally understand no worries
thank you
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Old 01-17-2018, 11:42 PM   #28
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Default Re: hp f2105 monitor black screen

i decided to do some voltage reading comparison between the good working monitor, that you gave me and the one that i had, that doesnt work. and i have found an issue with mine but im not sure what to make of it. checking the voltage at F851 and F852 the voltage fluctuates between 10v and 14v. the voltage at the same locations (F851 & F852) , on the good monitor, is a steady 18.98v Any ideas as to what i should check next?
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Old 02-07-2018, 11:39 PM   #29
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Default Re: hp f2105 monitor black screen

So i was able to fix the issue with the power supply board. I decided to replace the remaining 3 CAPS that i hadnt changed at the beginning. see attached pic. Once i changed those caps, the monitor powered on, solid blue light, backlight came on and it was even detected by windows 7, once i attached the video cable to it. But nothing was showing up on the display, not even the OSD Menu.
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File Type: jpg IMG_1785f1.jpg (359.9 KB, 4 views)
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Old 02-07-2018, 11:46 PM   #30
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Default Re: hp f2105 monitor black screen

********PROBLEM SOLVED********

Attached are some pics of the problem component, although im glad to have found it, im not very happy that i have to replace the Main (Logic) Board. But it is what it is..... if i can find one cheap enough, ill buy it and post the results.
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File Type: jpg lb1.JPG (1.61 MB, 10 views)
File Type: jpg lb2.jpg (565.7 KB, 9 views)
File Type: jpg lb3.JPG (2.11 MB, 8 views)
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Old 02-08-2018, 07:07 PM   #31
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Default Re: hp f2105 monitor black screen

Ouch. One of the voltage regulators has likely shorted, and would explain the blown fuse.

The voltage regulator failure could well have been caused by the bad capacitors.
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Old 02-09-2018, 05:13 PM   #32
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Default Re: hp f2105 monitor black screen

yea OUCH pretty much sums it up.... i hate when the end result is like this (being a component that i cant replace) im a mechanic by trade and instinctively my thoughts are to fix something, rather than replace. but it is what it is cant win 'em all. hope this tread helps someone in the future
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Old 02-09-2018, 06:02 PM   #33
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Default Re: hp f2105 monitor black screen

Not impossible, you could buy here: https://www.utsource.net/itm/p/4911066.html
And soldering QFP is much easier than BGA...

The problem is if it needs custom firmware, which is not loaded from an external EEPROM. Then you need the custom programmer for those MSTAR ICs, and of course, the code.
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Old 02-10-2018, 11:21 AM   #34
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Default Re: hp f2105 monitor black screen

What you could do is look on eBay etc for a universal panel driver board. That would let you use the monitor again. Though I don't know about image quality etc.

Might be cheaper than trying to find an exact replacement scalar board.
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Old 03-04-2018, 12:34 AM   #35
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Default Re: hp f2105 monitor black screen

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What you could do is look on eBay etc for a universal panel driver board. That would let you use the monitor again. Though I don't know about image quality etc.

Might be cheaper than trying to find an exact replacement scalar board.
yea i found a replacement board amd installed it. but still not showing anything on screen.
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Old 03-04-2018, 09:18 PM   #36
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Default Re: hp f2105 monitor black screen

****FIXED****


Finally got it working like a champ. After replacing the Main Board, i went through and RE-checked all my solder connections on the power supply board. and voila!

What i have learned from all this.... When replacing the electrolytic caps, change ALL, even the tiny ones as well. they didnt look bad and i under estimated their potential for failure. Also when ordering new caps, double check their physical measurements as well as their electrical measurements. Caps are so inexpensive, compared to the price of a new monitor or whatever you are attempting to repair, that you might was well replace all of them. Although i did not have one, schematics of the board will save alot of time and headache.


A BIG THANK YOU to all of you who offered your help i greatly appreciate it
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Old 03-08-2018, 01:17 PM   #37
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Default Re: hp f2105 monitor black screen

Good job!.
So what is the final fix to get it to work when the replacement board in your post #35 still shows nothing on the screen?
The one I gave you is still working?
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Old 03-09-2018, 05:33 AM   #38
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Default Re: hp f2105 monitor black screen

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Good job!.
So what is the final fix to get it to work when the replacement board in your post #35 still shows nothing on the screen?
The one I gave you is still working?
Well thats a good question... im wanting to say a bad solder joint on the power supply board. thats because after replacing the logic board, i still had nothing, and so i decided that ill recheck all the solder joints that i had done previously as well as any questionable looking joints. Then i fired it up and VOILA it started working. i now have had it running for 5days straight with no hicups whatsoever
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