Hi all,
does anyone perhaps have a schematic or service manual for an AOC monitor (1440p) of this type:
CQ32G1
CQ27G1
Q27G2U
They all seem to use a similar video and power board (it has an external power brick).
I've seen various reports of this AOC monitor type that sometimes provides power on logo and display, but most of the time only white back ground.
There are no markings for voltages on the boards and regulator part numbers are a bit elusive to determine the output voltage.
[url]https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-computer-displays/3213137-aoc-27-monitor-q27g2wg4-doesn-t-display-logo-or-image-on-screen[/url]...
doorzon
Member
Last Activity: 04-21-2024, 03:17 AM
Joined: 06-15-2015
Location: Utrecht
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Schematic request for AOC CQ32G1 or CQ27G1 or Q27G2U monitor
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Hi,
I see there are no responses yet to you post. I have the same kind of monitor (Q27G2U/BK with the same symptoms.
Backlight is working and sometimes when switching sources between HDMI ports or after power on it shows the AOC logo and will work fine with a video signal up to 1440p, until the input is interrupted and the problem comes back.
I've replaced the video board that connects to the TCON with a second hand one, which does not solve the problem. Hard to tell of course if the replacement is also broken.
The previous owner said it might be related to the cable... -
AOC AGON AG273QCG refresh problem picture shifts
Hi all,
hopefully someone on this board has an idea on how to begin with troubleshooting this problem.
The monitor AOC AGON AG273QCG (curved 27" QHD monitor) has problems refreshing every 1 to 2 seconds or so. A line appears in the middle of the screen and the lower half of the screen is shifted to the right.
See attached picture.
I am leaning towards an issue with bad soldering of the graphics chip, because the problem used to go away after some time (minutes) but now it is here to stay.
However, this could also be related... -
Re: LG 27GL63T-B completely dead
Hi all,
have a LG 27GL63T as well with IC401 broken. There was no 1.2V and 1.8V, but the IC did not get hot.
Ordered some new MP9148GJ-Z MP9148GJ IAKX SOT23-8 from Aliexpress since local suppliers had no stock.
Data sheet:
[url]https://www.monolithicpower.com/en/documentview/productdocument/index/version/2/document_type/Datasheet/lang/en/sku/MP9148GJ/document_id/1013/[/url]
With a bit of effort and lots of flux the chip was replaced. Monitor worked fine again straight after that. I did not verify...Last edited by doorzon; 02-08-2023, 03:21 PM.Leave a comment:
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KFA2 GTX 1080 video card not recognised, no output
Hi all,
With the outrageous prices of new video cards out there I've put some more effort into trying to fix an older card (repairing stuff is always a good idea in my mind, but the learning curve for the video cards seemed steep).
The video card is of GTX 1080 type (GP104 chip) that does not show up on the PCIE bus BIOS overview. It also does not provide any signal out on any of the ports (figures I suppose if is not seen by the motherboard).
Card type:
KFA2 EX OC GTX1080
[url]https://www.techpowerup.com/gpu-specs/kfa2-gtx-1080-exoc.b3837[/url]... -
Re: Samsung SyncMaster 2493HM - BN44-00195A - no power
Hi R_J,
thanks, will do. appreciate the assistance.
regards,
doorzonLeave a comment:
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Re: Samsung SyncMaster 2493HM - BN44-00195A - no power
Hi R_J,
thanks for the quick reply. After I did some measurements I decided to put the monitor back together partially. After this the power supply started to work again.
So it looks like there is a loose contact somewhere on the power PCB. Standby voltage is there as well as the 24V. Monitor now works as before.
If the problem comes back I'll pore some more time into this one. It's hard to find a fault if the damn thing is working ;-)
The high voltage transformers on the CFL PCB do make...Leave a comment:
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Samsung SyncMaster 2493HM - BN44-00195A - no power
Hi all,
wondering if anyone has experience with the following problem.
I have a Samsung SyncMaster 2493HM here with the infamous BN44-00195A power supply board.
Been reading a lot of posts here on the forum about one or another issue with this power supply. In my case, the monitor is dead, the blue light does not turn on.
When the PCB has power, I get 0.25V on the 5.3V, no voltage on 24V. The voltage across the main cap is around 310V, which indicates an issue with the PFC circuit according to other posts in this forum?
All fuses are good,... -
Re: Viewsonic VX2260WM LCD grey screen with lines
Hi People,
sorry for the late reply. It's been holidays in NZ and the site was unavailable for a while.
The caps have been replaced on these monitors, but no such luck fixing them. It seems that in spite of all the effort, the issue is with the LCD screen itself, as 1Supertech indicated in one of the earlier posts.
After taking apart the LCD itself, I've come to the conclusion that repair is not possible, but the monitors are a very nice uniform light source without the LCD glass panel in it.
...Leave a comment:
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Re: Viewsonic VX2260WM LCD grey screen with lines
Hi,
Between VDDG and VDDA: 33k4
VGGD - GND: 29k5
VDDA - GND: 1k8
D501K - VDDA: 0 R
D501K - VDDG: 31k4
Values are practically the same in both directions with my cheap DMM. Compared to 1% metal film resistors, the DMM seems reasonably accurate.
Diode testing D501 (in circuit) gives values 165 and 850 with my DMM.
Normally I'd expect one direction to be open but there are likely other components interfering with the testing.
So I took out...Leave a comment:
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Re: Viewsonic VX2260WM LCD grey screen with lines
Hi Momaka,
attached the pictures of the TCON component side.
I don't have access to my oscilloscope yet, otherwise I could look for excessive ripple on the VCC and VUSB on the power supply board. Maybe I'll just replace the caps on the board since it's little effort and cost. Only the wait time to get these shipped to New Zealand ;-). I suppose you learn to be patient when living on an island.
The fuse on the TCON is ok.
Will update when I have some more info.
thanks,...Leave a comment:
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Re: Viewsonic VX2260WM LCD grey screen with lines
Had a bit more time to do some measuring on the TCON board.
Since I have two monitors with the same symptoms, I swapped the electronics with the LCDs. The other LCD shows some information from the video input and also shows the OSD, however the response of the OSD or changes to the video input take 5 to 10 seconds to display. Brightness is also way too high, but adjusting it in the OSD does not really change a lot. Adjusting the VR on the TCON can only make it more bright.
Voltages are the same on both...Leave a comment:
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Re: Viewsonic VX2260WM LCD grey screen with lines
Hi all,
thanks for the replies. I've uploaded some photos of the power PCB, LCD and TCON.
thanks,
doorzon...Leave a comment:
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Viewsonic VX2260WM LCD grey screen with lines
Hi all,
I'm trying to repair two Viewsonic VX2260WM CFL LCD monitors, but no luck so far.
The CFLs light up nicely, but the screen stays grey with vertical lines (see attachment).
and the expected voltages (23V, 5V, 3.3V, 1.2V) are all in the correct locations as shown in the service manual found on the internet.
There is 5V on VLCD on the TCON board, so all simple things look ok.
Did any of you see this before? Any pointers welcome.
doorzon... -
Re: New Members - please post your introductions here
Hi All,
It's good to see that so many people have the urge to fix electronics instead of contributing to a world of throw away and buy new. Loads of info on these forums, making this a good resource to find help and help others!Leave a comment:
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