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CrossOver 27Q LED/LED-P, 27M LED, & 2720MDP GOLD LED Monitor Club - Page 297

post #2961 of 6483
Hey WRXed

- i have the same buzz and pop - so FWIW that seems standard to the Gold.
BTW - I wrote AW about the empty HDMI port. He responded that the manufacturer is switching from HDMI 1 to 1.6 (might have the versions wrong). Doesn't really explain why its empty though. He said he would "compensate" for it...but haven't gotten any detail on that yet. Will let you know.

I'm currently using HDMI cable which doesn't allow the max resolution of the monitor. Mini-DisplayPort to DisplayPort cable arrives today. Purchased on Amazon. If it comes through flicker free, etc. I'll post the brand and link. I have a MBP Retina on the other end.

Interesting that at the apple store they don't have that type of cable and you have to go buy them 3rd party....
post #2962 of 6483
Quote:
Originally Posted by ghabhaducha View Post

Tehpsyc, sound analysis. I have a green PCB with 3 mosfets (does that mean 3 phases of power? I think so...not an expert though). Still, I have been running it off of that 200W voltage transformer that I mentioned earlier. Corresponding to what you said, I have seen a noticeable drop in temperature on the mosfet surface and the included power brick surface.
Question though, what exactly did you have to tell red-cap for him to send you a replacement PCB?

I had originally had a really bad flicker on my back light which I did not attribute to the overheating MOSFET (didn't know it was an issue). I had sent red-cap a video of the flickering, and then explained that the monitor's back light had completely died a day later. He was the one who decided it was my PCB that was having an issue and mailed the replacement. After he indicated he thought that the PCB was the issue I popped open the monitor and sure enough the MOSFET was burned up and discolored. So, I sent red-cap a confirmation picture of this and he agreed the PCB was the issue. I then did some reading through this thread knowing what to look for and found all the old information of others with this issue.

As far as the 3 mosfets, not sure honestly. I'm no expert in this area either, but from what I've read there haven't been any reports of the green board failing, so whatever is different about it appears to be protective of this issue. My 200W power converter should be arriving today, so I will report whether I notice temperature improvements and will probably do a full backlight burn-in test and see if I get any flickering.
post #2963 of 6483
I'm pretty sure there is a design flaw with the blue pcb. Here is a picture to compare the mosfets used in the blue and green pcb:



The mosfets used on the green pcb have double the ratings compared to the ones used on the blue pcb. The green pcb's seem to have 2-3 mosfets on them compared to the blue pcb which has only one mosfet on it. I'm only guessing here, but i think the mosfet is operating out of its specifications thus producing excessive heat which kills the mosfet. By fixing a heat sink on the mosfet you can prolong the life of the mosfet (less heat, less degradation) but i think it will die eventually anyway. But then, i'm only guessing..
post #2964 of 6483
Quote:
Originally Posted by Karail View Post

I'm pretty sure there is a design flaw with the blue pcb. Here is a picture to compare the mosfets used in the blue and green pcb:

The mosfets used on the green pcb have double the ratings compared to the ones used on the blue pcb. The green pcb's seem to have 2-3 mosfets on them compared to the blue pcb which has only one mosfet on it. I'm only guessing here, but i think the mosfet is operating out of its specifications thus producing excessive heat which kills the mosfet. By fixing a heat sink on the mosfet you can prolong the life of the mosfet (less heat, less degradation) but i think it will die eventually anyway. But then, i'm only guessing..

Well as I was reading through your post my monitor started flickering again despite being on the surge/UPS that seemed to sustain it for the last day. My power converter gets here today, do you think the MOSFET issue is because of the different voltages or is just a design flaw? I've already sent a message to red-cap requesting a green PCB. Does anyone know if there's a seller/source who would sell the green PCB? Red-cap's english isn't great so trying to specifically request a different PCB might be challenging.
post #2965 of 6483
Quote:
Originally Posted by tehpsyc View Post

Well as I was reading through your post my monitor started flickering again despite being on the surge/UPS that seemed to sustain it for the last day. My power converter gets here today, do you think the MOSFET issue is because of the different voltages or is just a design flaw?

I think it could be both, a design flaw and different voltages. I can't tell for sure, but most likely its a prolem with the blue/teal pcb. We have not seen a person with a green pcb to encounter this problem. Not that i know of.
post #2966 of 6483
I sent a message to red-cap asking for a green replacement PCB. For those looking to request it as well, the model is apparently FIF22LD-04A. I also sent a message to AW to see if he'd be willing to sell me one, or perhaps list is as an item on eBay so many of us could purchase it. I'll report back with his response, but all the sellers are still on holiday I think. I'll also let you know if my 200W converter remedies the situation when it arrives.

EDIT: Messaged green-sum as well
Edited by tehpsyc - 10/3/12 at 8:37am
post #2967 of 6483
I have not yet taken apart my monitor, but from what I can see I have the GREEN PCB, upon further inspection I see another smaller TEAL PCB which the DVI and power plug into. This TEAL one is not the board in question right?
New i7 950 build
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New i7 950 build
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post #2968 of 6483
Quote:
Originally Posted by strap624 View Post

I have not yet taken apart my monitor, but from what I can see I have the GREEN PCB, upon further inspection I see another smaller TEAL PCB which the DVI and power plug into. This TEAL one is not the board in question right?

Correct, the teal PCB in the center of the monitor is the main board, and not the cause of the backlight issues. Its the smaller daughterboard to the right (facing the back of the monitor) that you want to be green.
post #2969 of 6483
Just checked myself, I have teal PCBs where the vesa mounting is and then another green PCB on the right hand side of that, is that what I'm looking for? Haven't been using the 27Qs since I started reading about the mosfets burning out.
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post #2970 of 6483
Quote:
Originally Posted by Azefore View Post

Just checked myself, I have teal PCBs where the vesa mounting is and then another green PCB on the right hand side of that, is that what I'm looking for? Haven't been using the 27Qs since I started reading about the mosfets burning out.

Sounds like you're in the clear. As far as I know, only the LED controller board comes in two variants. So if you see a green board, you're probably ok since the only green board seems to be the good LED controller. The main board is teal, and if the LED controller matches in color you may have a MOSFET issue. I'll trade you my teal one thumb.gif
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