Acer V5-531 Does not turn on

[Mad Capper]

Re: Acer V5-531 Does not turn on

Yes, I understand checking one by one to accurately diagnose the problem and I thank you for your assistance.

So it is your opinion that both U2701 and PU4103 need to be replaced, correct?

I was hoping that U2701 was still good because it will be even more difficult for me to replace then PU4103 which will be a challenge also.

[Mad Capper]

Re: Acer V5-531 Does not turn on



By "at" what pin do you mean? If pin 14, S5_ENABLE, this is the readings. If not pin 14 what pin should I measure at?

........GOOD OFF U2701......GOOD ON U2701.........BAD OFF U2701
Pin 14...............0V.........................3.3V.......................3.3V

GOOD OFF PQ4101 ......GOOD ON PQ4101.............BAD OFF PQ4101
1.............GND..........................GND........................GND
2.............0V............................3.3V........................3.3V...

[Mad Capper]

Re: Acer V5-531 Does not turn on

Unfortunatley, I am confused. I understand all that you have said. I am aware of S states. What I do not understand is why when off my BAD board has many of the voltage readings as though it were actually on.



I understand this and follow start up process and schematic. Why does KBC already have 3.3V on pin 14 when only plugged in and no button pressed? If 3.3V is already there when I plug in the power why does the motherboard not start automatically? Are all the problems from PU4103? I could understand that the failure...

[Mad Capper]

Re: Acer V5-531 Does not turn on

Thank you for the explanation.


If this is so then the readings, e.g. the 3.3V on U2701 pin 14, 0.9V on PU4103 pins 1 & 6, 3.2V on PQ4101 pins 2 & 5 etc., I am getting would indicate that even when off the BAD board is actually on. Some of the readings that don't make sense then are because the board is potentially not actually off and therefore I cannot get those readings. Does this mean that the board is on? Why and how is the board on? And how do I turn it off?

There are other readings that do not...

[Mad Capper]

Re: Acer V5-531 Does not turn on

In response to stingerchamp:



They are not. BAD board meaures 0.9V on pin 1 and 6, not 5V. Therefore, you would say that PU4103 is bad, correct?


I believe you mean pin 1 and 6, correct? Are you saying this 5V is created internally in PU4103 and not from an external source? And this 5V is then output to PQ4101 pins 3 & 6?



All pins labeled 3D3V_AUX_KBC on and surrounding Super I/O have 3.3V



They are.



...

[Mad Capper]

Re: Acer V5-531 Does not turn on

There is not a different measurement on pin 1 and 2 of RN2705 from one board to the next. It was an error in my original post. Again, go with the current information you quoted.

We knew something was wrong with S5_ENABLE from my first post. As seen from from the S5_ENABLE test point.

GOOD AFTP12 S5_ENABLE..........BAD AFTP12
............0V....................................3.35V


D3601 on BAD board checks out good, same as on GOOD board. I have included the measurement again and added pin...

[Mad Capper]

Re: Acer V5-531 Does not turn on

There is no component PR2705, do you mean RN2705?

Sorry copy/paste missed pin 4. Also I re-measured, disregard original measurements for RN2705 and use these.

GOOD RN2705 BAD RN2705
1...3.3V...............3.3V
2...3.3V...............3.3V
3...0V.................3.3V
4...3.3V..............3.3V

See boardview file for Q2703 pin assignments and reference schematic. Starting at 3 o'clock position going anti-clockwise pins are 1(D, 3DV3_AUX_KBC), 2(G, EC_ENABLE#), 3(S, 3DV3_AUX_S5...

[Mad Capper]

Re: Acer V5-531 Does not turn on

Here is the information you requested. Can you explain to me how this is relevant, I do not understand. I do not know how it works without it but it does.


GOOD Q2703..........BAD Q2703
1..........3.3V.................3.3V
2..........0V....................0V
3..........3.3V.................3.3V

Q2703 is in the upper right hand corner of the image to the upper right of the Super I/O...

[Mad Capper]

Re: Acer V5-531 Does not turn on

Yes, I have the VREG 3V and VREG 5V outputs

GOOD PU4103..........BAD PU4103
8...........3.38V.................3.37V
17..........5V....................5.04V

All PU4103 readings are the same on GOOD and OLD +/- for all pins except the following

GOOD PU4103..........BAD PU4103
1..........5V....................0.9V
6..........5V....................0.9V
19.........0V...................5V

Are pins 1 and 6 input or output?

[Mad Capper]

Re: Acer V5-531 Does not turn on

CMOS battery is a coin cell at 3.12V

I did what you suggested and it has no effect. The condition is still the same.

To be clear I was only referring to PQ4101 when saying that the GOOD board voltages when turned on were says as the corresponding component on the BAD board when off. I did not check other component voltages when the GOOD board was turned on. I just happened to note this during my testing and mentioned it as it seemed interesting to have the same reading when one was on as the other off.

[Mad Capper]

Re: Acer V5-531 Does not turn on

I agree I need S5_ENABLE. From my reading of the schematic it originates from pin 14 of U2701 and should be 0V as per my good board. As it is 3.3V I do not know if there is an internal short in U2701 or 3.3V is being fed back to that pin because something else is faulty.

I do not know what the sequence between these three components I mentioned is. One could be faulty causing the readings I am getting or perhaps multiple are faulty.

Are pins 1 and 6 of PU4103 supposed to be outputs of 5V that go to PQ4101 pins 3 and...

[Mad Capper]

Re: Acer V5-531 Does not turn on

There is no component at location on the board.

In what I have done so far when the schematic says there is no component at a location my board matches up. This one is a discrepancy.

The schematic is for the closest I could find. The schematic is for Petra UMA MB 11324 Revision -1 PCB P/N 48.4VM02.[COLOR="Red"]001[/COLOR]

My mother board is 11324-1 48.4VM02.[COLOR="red"]011[/COLOR]

So not very far off, but a few slight differences.

I believe the problem...

[Mad Capper]

Re: Acer V5-531 Does not turn on

I am getting 3V on pin 3 of PWRCN1 on both machines. I have removed the ribbon cable and power button from the non-working computer and it works fine on the working one.

[Mad Capper]

Re: Acer V5-531 Does not turn on

I took the AC power supply and battery from the working laptop and used them on the non-working laptop to see if those were the problem. An easy initial test to rule them out.

I would plug in the power supply or battery and try to turn on the computer. I did this a few times with each battery and power supply, in various combinations. It worked once but I think it was just a coincidence. The power supply and battery work fine in the known good laptop. So the problem lies on the motherboard.

[Mad Capper]

Attached are the motherboard schematic and boardview and a datasheet for an IC. Change .doc to .GR for boardview file.

Never had a problem with it until now. The laptop would turn on if put to sleep but when shut down it would not turn back on. I have another of the exact same laptop so I switched chargers and batteries to see if that worked. It did once after many swaps and power button presses. I am not sure the combination that worked but it did not seem to do it immediately, i.e. I just kept swapping over and over until it came on. When I put it to sleep again or shutdown, I...

[Mad Capper]

Re: Samsung LN32A330J1D - BN44-00191B No secondary No Standby Sort of

Thought I would update the situation. I finally just received the PFC IC from China. I took a month to get here, about twice as long as my last purchase from there. Better late than never I guess.

I put it in and shorted the STBY and ON\OFF and got 400V. I plugged all connectors back in and it fired right up. All is well. Another one saved.

Thank you again to all who assisted me. I appreciate your time and willingness to help those of us who do not have the experience and knowledge...

[Mad Capper]

Re: Samsung LN32A330J1D - BN44-00191B No secondary No Standby Sort of

I hope the mainboard is good to after putting in the time and money so far. Is there anything in particular I should be looking for? Other than a visual inspection is there anything else at this point that can be done to verify that the mainboard is still good?

I have read of power surges coming back through the HDMI and damaging PSU and mainboards. Out of curiosity, because of this danger does anyone use or recommend the HDMI surge protectors that I have seen for sale?

Thanks

[Mad Capper]

Re: Samsung LN32A330J1D - BN44-00191B No secondary No Standby Sort of

Thanks for the additional information. I guess I need a new FAN7530 before we can go any further.

I know there is not much certainty in making further prognosis with out the PFC working, but knowing as much as everyone here does about LCD displays how often is the mainboard actually bad vs only a PSU problem.

I ask because my experience may bias what and average ratio actually is. If this one is fixed with the PSU repair then I have twice as many that have been fixed with only PSU...

[Mad Capper]

Re: Samsung LN32A330J1D - BN44-00191B No secondary No Standby Sort of



The PFC MOSFET is QP801S, correct? If so then yes I did not replace the PFC IC when that was replaced. If it is bad would this account for the behavior I have mentioned or the readings I get?

So that I may understand more fully, if the PFC IC is bad why does the cycling that I mentioned occur?

So then I did it correct by connecting the ON/OFF to STBY?

My most recent repair was on another Samsung PSU BN44-00264A which also uses the FAN7530. It was good...

[Mad Capper]

Re: Samsung LN32A330J1D - BN44-00191B No secondary No Standby Sort of



I flipped the PSU over and took readings from ICP801S FAN7530
1 1.029V
2 0V
3 increasing mV
4 0
5 0
6 GND
7 0
8 15.02V

Obviously not what these should be so I do not know if as you say what it is "fed" is the problem or that the PFC IC itself is bad? Based on the datasheet I think pin 1,2,4,5,8 are input and 3,7 are output but I am not certain.




I am not sure I understand. ON/OFF...