reessi
Badcaps Veteran
Last Activity: Yesterday, 04:37 PM
Joined: 01-04-2016
Location: sheffield
-
No jumper specifically, I mean the jumpers that separate the output of the power supply's to the circuits they feed.
You need to remove the jumpers from the outputs of the power supply's that feed the Video Ram and the GPU.
I will try to look later or tomorrow on the Schematics.Leave a comment:
-
I'm happy to report I fixed it! Although I think I should have spotted it before posting!
I neglected to check the power supply to the chip (RT8816GB). After checking the datasheet I realised it should be 5v on pin 18 (PVCC) but it was at 1v!
I then noticed there was a burnt dot in the middle of the 2.2ohm resistor (PRW1) feeding it from 5v Always. There was 5v before it. It was partially open, I replaced it and it burnt again. After a bit more messing around I realised the capacitor (PCW17) connected to it was partial short at 200ohms.
As it wasn't full...Leave a comment:
-
If it is getting as far as windows then yeah I don't think it is the bios. You could try disabling the secondary graphics chip and see if it it runs ok on the integrated. You would have to disable power to the video ram and the gpu. Do you have the necessary equipment / knowledge to do this? I don't have any other ideas after that..
When the screen goes black at windows logon does anything display on the external monitor?
When it doesn't boot are all the power rails at the correct voltage? You can see them all on page 4 of the schematic.
Actually since there...Last edited by reessi; 11-24-2024, 08:09 AM.Leave a comment:
-
So that is 1.2v power supply according to the schematic. Un-solder jumper PJM2 and then see which side of that jumper the short is on. It feeds the Ram and CPU. Remove the ram if not removed to see if that makes a difference. Otherwise if it is on CPU side and not the ram then could be dead CPU.
But I am not sure what resistance that cpu should be, Can be pretty low.
EDIT - I just checked an Acer Predator 300 Helios ( [B]LA-J891P[/B]) that I am working on that still boots but with secondary GPU issue and the CPU measures 6 ohms on one coil and 3 ohms on the others....Leave a comment:
-
Acer Predator Helios 300 - FH52M LA-J891P - MISSING +1.35VSDGPU!
Hello:
The GPU is recognised in windows but with an error, up on testing I found +1.35VSDGPU is missing for the Video Ram.
Coils (PLW1 & PLW2) read 78ohms on the video ram side when I lifted one side to isolate the video ram. I believe this is normal, let me know please?
Up on powering up no attempt is seen of any voltage on the coils.
The power supply (RT8816B) is receiving 2.6v on the enable pin.
There is 19v on the switching Mosfets (PQW1 & PQW2) via PLW3.
Power good output from RT8816GB remains at... -
My issue was only related to the power button, sounds you like you had a charging issue and now you have the boot looping because the update was interrupted like mon2 has said.. OS can be corrupted interrupting it..
After re-installing you can then address the charging issue if still existing..
I never figured out he issue.. It would always boot loop with the power button so I ordered another for testing and it booted but then I put the old one back in to test and strangely that one worked! I was hoping to meter out the flex on each button to see if a difference but it...Leave a comment:
-
So 1.8v is ok on +VCCIN_AUX_PCH even though it says 1.05v in the schematic? Is it not strange there is 0.66v appearing on the line when the power supply is removed?
Would Boot Guard stop it from turning on though?
CheersLeave a comment:
-
Hello,
Yeah it may well be faulty, it was always a risk..
+3VL_RTC is working fine when bios battery is plugged and comes out on some resistors next to the PCH.
I hadn't realised that since the 1.8V ALW started working some other voltages have appeared.
But the 1.05v on the schematic is labelled as +VCCIN_AUX_PCH, this is coming on at 1.8v! Can that be a fault with the power supply? There is no short showing on this coil. When I lifted the coil and measured voltage it shows 0.4v when laptop powered on on PCH side.. Can that be coming out of the...Last edited by reessi; 10-31-2024, 11:00 AM.Leave a comment:
-
Actually on the Acer machine the 2 GPU coils next to each other (GPU Power supply) measure 0 ohms and the one on its own measures 50ohms, this is the VRAM power supply.
On the Dell all GPU coils measure 0 ohms.Leave a comment:
-
Acer Alienware Nitro 5 (GH51G LA-L181P Rev: 1C) & Dell Alienware M15 (GDP50 LA-k452P Rev:1) - Both Shorted PCH (SRKMA)!
Hello:
I have both these laptops that appeared to have the same fault so I thought I would have a go at replacing the PCH as something to learn, they both are using the same PCH.
[U][B]I started on the ACER:[/B][/U]
Up on connecting power no signs of life but current is consumed from the bench power supply and the PCH is hot.
All the caps on the top of the PCH are showing 0 ohms and the 3.3v rail is shorted.
I followed the videos from Sorin, Electronics Repair School on Youtube heating from the bottom to install. I practised on around...Last edited by reessi; 10-29-2024, 11:57 AM. -
Hello,
Yes it worked the one you sent me so I must have compiled it wrong!
Many thanks.Leave a comment:
-
Just curious why it is released as source code only and not as an exe? Is there a way to run it with out compiling?
CheersLeave a comment:
-
Hello,
Yes same error or a different one attached.
If I load a bios with out the Intel Engine then it correctly states no intel engine found,
Drag and drop is the same..
Do you think I compiled it wrong?
I followed the instructions to the letter..
I did get an error stating something about a path is not loaded, I could load it if I wanted in yellow but the compiling continued.. I'll post a screen shot shortly.
Is there a pre-compiled one I can download to try..
Cheers....Leave a comment:
-
Hello, When I run the resulting Exe, it loads and I enter the file location:
C:\3.bin
After that I get the errors shown in the pic...
Can anyone help please?
Cheers...Leave a comment:
-
Many thanks for the explanation. I have ordered some 3w ones from Aliexpress.Leave a comment:
-
So I looked up some more datasheets and some are saying 20a constant current but only 2w power rating, can anyone explain this.. CheersLeave a comment:
-
So another thing that doesn't make sense is that the block states 55w 2A and 21v * 2a is 42w at least. But these 5 SMD resistors cannot be at least 10W each!!!
So how can this be... When I look them up to buy, a lot are rated at 1 or 2 w.. they are labelled as specifically current sense resistors,Leave a comment:
-
Fair enough. I was thinking if it wasn't for a battery charger I would just fit what I had on hand.
Interestingly it is noted that although the adapter states 20v it outputs 21.65v. But for the 18v lithium battery to be charged correctly you would need 5 x 4.2v = 21v anyway. So I am assuming that voltage output is correct.
I have also just noted that in the charger end there is another bank of 5 x R300 resistors on the same rail with similar looking feedback.
To be fair I was thinking it was for the voltage feedback but the current makes more s...Leave a comment:
-
20v / 2A SMPS for a Battery Charger - Explanation of Blown Resistors Please..
Hello,
My friend asked me to replace the wire going from this SMPS 20v adapter to the charger for a 18v Lithium Battery for a drill.
The cable had frayed and been touching, as a result the 5 Paralleled R200 (0.2 ohm) resistors had blown O/C, they are connecting the main -ve rail to the output wire.
The output was jumping around 13v and dis-appeared when a load like the charger was connected, they measured 900ohms.
I experimented by replacing at first a single 0 ohm and then a 2.2ohm in and the output was restored at 21.62v and 21.65v respectively...
No activity results to display
Leave a comment: