Aspire 5742G - erratic behaviour, dunno what to try anymore

[Dan81]

As the title states:

I have here an Acer 5742G, mainboard model NEW70 LA-5891P rev 1.0. CPU is an Core i5 430M, GPU is Radeon HD6370M (aka Mobility HD5470). Other specs include 4GB of DDR3 and a 320GB WD Black.

Issues:

- powers and runs from anywhere ranging to 10 seconds up to 3-5 minutes or so
- fan runs at full speed

What I have tried:

- reflashed both main BIOS and EC at least 10 times, same behaviour across at least three diferent BIOS versions - 1.07, 1.23 and 1.30 (since the BIOS flasher reports PEW71)
- repasted both CPU and GPU, but temps were good beforehand as well - 39*C is literally where it sits at because of the fan running at full speed.

Is there anything I can do, or is it safe to say the board is trash?

[Stevedb]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

Hi

Did you flash the bios with a programmer?
Did you see screen when the laptop is on?
Did you do clean me region before you flash bios.
What are the voltages on evey coil and the resistances to ground?

Regards

[Dan81]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

It's kinda late but I can answer some of those questions:

Yes, I did flash the BIOS (and EC chip as well!) with a CH341A programmer and Colibri programming software (specifically because it has the compare feature.).

As for the screen, yes, it always comes up.

The Clean ME region thing... I used already cleaned ME BIOS files for that matter - specifically searched them on here and managed to get it working. The only non clean dump I used was BIOS 1.23.

As for the voltages and resistances, I haven't gotten to check them, but I'll be sure to post them up tomorrow.

[SMDFlea]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

Theres a similar thread from a member who had the same issue https://www.badcaps.net/forum/showth...ighlight=NEW70

[reformatt]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

Generally fast fan with low CPU temps is a sensor problem, like missing fan tach. Fan speed is driven by U35/EN_DFAN1 from the EC. Sensor feedback is via FAN_SPEED1 to the EC. So check this area first.

If that checks ok, go over the other thermal sensors on the board. PU30/PH1/PH2 would be a good starting point. Issue here could shut the system off by pulling mainpwon low.

If you can get into Windows, the Intel Extreme Tuning Utility can at least tell you what is going on with throttling etc, however I don't know if it supports such an old CPU.

[Dan81]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

Theres a similar thread from a member who had the same issue https://www.badcaps.net/forum/showth...ighlight=NEW70

That was one of the threads I've been looking at for almost the whole day. Flashing the files in there gave me a black screen though the machine DOES boot into Windows.

Generally fast fan with low CPU temps is a sensor problem, like missing fan tach. Fan speed is driven by U35/EN_DFAN1 from the EC. Sensor feedback is via FAN_SPEED1 to the EC. So check this area first.

If that checks ok, go over the other thermal sensors on the board. PU30/PH1/PH2 would be a good starting point. Issue here could shut the system off by pulling mainpwon low.

If you can get into Windows, the Intel Extreme Tuning Utility can at least tell you what is going on with throttling etc, however I don't know if it supports such an old CPU.

The thing is, HWMonitor does report the speed of the fan, so the tach sensor does indeed work - sometimes it does switch fan speeds but in a totally chaotic way, like it's pulsating for 2 or so seconds.

[mcplslg123]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

Could be failing GPU itself.

[Dan81]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

Are you sure? I don't see any artefacting when inside Windows.

If so, do you think a reflow would bring up the GPU as the cause of the erratic fan behaviour? One thing I noticed is the GPU doesn't have any protection foil over it, but the HM55 chipset does.

[reformatt]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

If you can get into Windows, check Task Manager for CPU speed and see if it's being throttled - this could account for the erratic fan speed. Throttlestop is an app you can use to check. Also Intel Extreme Tuning Utility does have some indications as to why it's being throttled if that is the case.

[Dan81]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

No throttling as much as I could see. CPU temps aren't anywhere close near throttling - 36-55*C is the maximum I've recorded through HWMonitor. I'd reckon it would have to get in the high 70s to 80s to be even throttling.

At this point, I feel like I'd have better luck buying another board with a GT540M (the LA-5893P) that might just have a corrupted EC (seller reports it sat 1 year doing nothing, then suddenly didn't want to power on. I just have an myriad of BIOS for that one too, as I happen to have a beaten up and soldered to kingdom come 5893P that won't power on at all.) and beat that horse.

[Dan81]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

And this one doesn't turn on anymore either. Great.

[reformatt]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

Throttling doesn’t occur just because of temperature. Can be many reasons, like missing sensor data or non-genuine charger for example (like on Dells). It can be asserted by the CPU or the system itself.

[Dan81]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

HWMonitor detected all thermal sensors though - CPU, MB temp (which I assume is the PCH temp), and ultimately, GPU temp.

As for non-genuine charger - ASUS, Acer, and some HPs use an totally bog-standard plug. Acer and ASUS are literally 4 wires, out of which 2 are positive and 2 are negative. Same goes for ASUS mostly, and HPs usually depends, but they're mostly + and - with some resistor that acts as the 3rd wire.

Anyways, thanks for all your help everyone. I've decided to give up on both mobos I have (LA-5891P and 5893P) and use a LA-5911P (Phenom II N620 + HD5650 1GB) in its place, out of a pretty mangled 5552G. Both are my units by the way.

As for the 5742G, I just ordered a new one w/ GT540M and a i3-370M, and will upgrade it once it gets here (and possibly spraypaint its case white, to make it look custom)

[piernov]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

The LA-5911P is the worst out of the 3 unfortunately. AMD from 2010 so lots of wasted power, worse performance than Intel and very high failure rate of RS880M northbridge.

[Dan81]

Re: Aspire 5742G - erratic behaviour, dunno what to try anymore

Mine did have a failed RS880M, but considering the thermal pad literally crumbled, I don't blame it. I slapped a Phenom (it came with the lowest Athlon II P320, that thing ran slow like hell. Even a low end Pentium T4xxx was better than it.) and a copper shim over the RS880M. Temps are at bay now, surprisingly, and it does run 1080p decently.

Not the best choice (I'm not a big fan of AMDs either) but it runs way too well to fiddle with it any further.

I've only had two units that are running EXCEPTIONALLY well and are tough as absolute nails - this 5552G mobo (NEW75 LA-5911P) and a whole Packard Bell LJ71 that's running a DDR2 based Athlon II M300 and a MXM 3.0b HD4570.

As for the 5742G, it's probably better that I went and looked for a variant that has the GT540M. Same performance as the HD5650 that the 5552G uses apparently. Now just to check what would the ideal CPU be that would go just right with the GT540M.