(347) 552-2258 [email protected]

A1286 820-3330 can't boot into OS,light video distortion

R

roy.ruan

New member
having a 820-3330 board, having similar situation like the 820-2915 board we handled a lot.

can't boot into OS, sometimes can see like yellowish color distortion, taped mux and no change. should be a common issue since this week having two of them with same issue and don't know where to start .

anyone came across with this case?

this model's GPU is pretty ok,not like the 2915 one as we tried replacing one previously,so do doubt on the circuits...just wondering what direction to go
 
S

SMMRepair

Member
edit: obviously not the LCD, my mistake completely. Don't want misinformation here, so removing post.
 
Last edited:
D

dukefawks

Administrator
How would the LCD affect booting???

Could still be a bad GPU or VRAM. GPU first then VRAM. Inspect for corrosion around GPU area too of course.
 
Gurmon

Gurmon

Member
Funny this i'm working on a similar issue today. Unit was showing some pink artefacts on the screen, with blocky patterns, which usually indicates bad GPU. However PP1V5R1V35_GPU_REG was only 1.5ohms. Vram was red hot after a couple of minutes.
I've replaced vram, pinky dots gone, but worse blocky patterns. Took Vram off, and display nice and clean. maybe I put on bad vram or gpu is bad as well. I'll crack it tomorrow.

Im starting to see a increase in 820-3330 boards from non liquid spill issues.
 
R

roy.ruan

New member
Nothing to do with the LCD for sure. I actually had seen this issue previously like few months ago on another machine.
I replaced the GPu and didn't get the problem fixed and finally gave up. now they come across again. that's why I didn't touch the GPU yet.
and yes it's extremely hot , but feels like normal for all these models with big GPU though so pretty confused and Im still checking and analyzing the circuit
 
R

roy.ruan

New member
yea come across a lot this year,I think can be a common fault on the circuit that we didn't found out yet.
The glue around VRAM are pretty nasty to remove of this model too
 
R

roy.ruan

New member
and appreciate the input bro, may let me know how it goes tomorrow. pretty expensive GPU ,I got it for like 50+ a piece. so don't want to waste another one at this moment
 
Gurmon

Gurmon

Member
Vram was noticeably hot on the board im working on.

Just to collate some more info, can you provide a resistance to GND measurement on L8360 ?
 
S

SMMRepair

Member
Yeah, obviously not the LCD at this point. We've refurbished maybe 100 MD103/104 and saw an unusually high number of LCD failures, with yellow or blue-tinting issues. In the worst cases, some would "hang" on the Apple logo (which was color-distorted), and "wouldn't boot" fully into the OS (turns out they were booting, but the LCDs were bad and not showing the login screen, only the discolored Apple logo). That's the only reason I mentioned the LCD at first; of course, if you tried several LCDs, then that's not the issue. This was just the first thing I thought of, and you hadn't mentioned trying several LCDs, so figured I'd mention it.

Certainly wasn't saying for sure that the LCD was 100% bad and should be replaced. Just that it's worth checking into; that's all. I'll edit that reply since it's clearly incorrect.
 
R

roy.ruan

New member
it's all good bro, still appreciate the input. can be anything when we do repairs, but this case I do see the same distortion with another screen so
 
R

roy.ruan

New member
but I did fix one of this board few weeks ago with shorted GPUVCORE circuit due to a bad cap, after repair , it was around that range as i remember.
and for GPUs of 2011 2012 , should be around 100 sth. 820-2915 is around 100 as I can remember..
 
R

roy.ruan

New member
definitely bottom of the pile, would give it a shot around the weekend and maybe replace the whole GPU first. the white glue of this model is really nasty. the 2011 model would come right off when you heat up, this 2012 model is just not the case
 
larossmann

larossmann

Administrator
Staff member
If you unplug the internal LCD and plug in a displayport screen does it boot and still have artifacts? I have several 3330s here with fine GPUs but that have CPUs with dying HD4000. Unplugging internal screen and plugging in external will force it to use the nvidia GPU rather than the integrated intel.
 
R

roy.ruan

New member
hey man, I just replaced the Vram and exactly same stuffs happening here!!!
I got the pin artifacts gone and blocks all over the screen. did you figure out?
 
Gurmon

Gurmon

Member
Hi Roy, sorry, haven't got round to it yet. Spent day support stuff. Im back on the board stuff tomorrow.
 
You must log in or register to reply here.
Top