Author Topic: Power taken during Fn + ZZZ mode  (Read 5614 times)

Unhban

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Power taken during Fn + ZZZ mode
« on: September 07, 2008, 09:48:59 PM »
Has anyone seen any stats for the power taken during the Fn + ZZZ mode which I presume is either a sleep or standby mode?

crylex

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Re: Power taken during Fn + ZZZ mode
« Reply #1 on: September 08, 2008, 12:04:24 AM »
Hi

During this sleep mode, I can still access the computer from an external computer with telnet, so the computer is still fully awake, I think its just the screen thats blanked.

Chris

Arakis

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Re: Power taken during Fn + ZZZ mode
« Reply #2 on: September 08, 2008, 06:43:36 AM »
I left the system in sleep mode last night and 8 hours late the battery was dead.

I'd agree, the fn+zzz key just turns the screen off.  :(

Phyl.

Unhban

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Re: Power taken during Fn + ZZZ mode
« Reply #3 on: September 08, 2008, 09:38:10 AM »
OK, that's what I thought... that it's just the screen that's turned off, to save power. So if I'm leaving the E for a few mins, even up to half an hour, it wouldn't be too bad to put it in this mode?

David

oldgrumpyman

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Re: Power taken during Fn + ZZZ mode
« Reply #4 on: November 23, 2008, 05:53:09 PM »
The screen (LCD) display fluorescent tube (CCFL) is not powered during sleep mode, as others have said.

But as should be evident from the heat felt on the left hand side of the screen case, the power supply for the CCFL is not turned off during sleep mode.   

The LCD inverter, as this sub-power supply is called, generates about 1500 volts to start the CCFL, and then something of the order of 700 volts to keep the CCFL lit.    So even without using the lit display, continuing to generate 700 volts from the rechargeable battery during sleep mode is going to drain the battery.   

For a very short time, using sleep mode powered only on batteries, may be more power efficient than powering-off and rebooting. 

But that's not generally the case, and the main use for the sleep mode is for near-instant on while powered by the mains adapter.

mewtwo

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Re: Power taken during Fn + ZZZ mode
« Reply #5 on: May 09, 2009, 03:18:16 AM »
Erm, are you sure that the screen is illuminated by a CCFL? I assumed some white LEDs were used - powering them off and on doesn't really 'cost' anything - the non existing latency between pressing the Zzz buttons and light on/off indicates LEDs, too

rodonn

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Re: Power taken during Fn + ZZZ mode
« Reply #6 on: May 09, 2009, 04:32:03 PM »
If it's LED then it's kicking out a lot of heat....

oldgrumpyman

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Re: Power taken during Fn + ZZZ mode
« Reply #7 on: May 10, 2009, 04:50:44 PM »
Erm, are you sure that the screen is illuminated by a CCFL? I assumed some white LEDs were used - powering them off and on doesn't really 'cost' anything - the non existing latency between pressing the Zzz buttons and light on/off indicates LEDs, too

@ mewtwo - Yes I am sure about the ONEt I had.
The non-existing latency does not indicate anything other than minimal delay. 
However the hot spot does indicate something, as Arakis posted above.  Heat means power is being used, and in the ONEt the CCFL's inverter will drain the battery on standby.
If you have a hot spot to the LHS of the screen, I doubt that you have LED illumination.
A LED driver chip on standby should be actually powered off until required,  by a switch that uses almost negligible power during standby,  and therefore should not generate heat or drain the battery.

The ONEt that was delivered to me was illuminated by a CCFL.  There was an inverter to the LHS of the screen,  as illustrated in photos of a Trendtac,  on a Dutch forum web site.  I didn't think it necessary to take a ONEt photo.  However I had one of the ONEts that were delivered on the first day of the Home Delivery distribution.   But I no longer have it, the WiFi failed and Elonex replaced it. 

Because of the failure of Adobe to provide a MIPSel Flash, I decided against long term use the ONEt, and bought a netbook that would support Flash.  It became obvious that with Adobe Air, more recent releases of Flash would not be fully functional unless run under Adobe Air - under which DRM can be offered by Adobe.  Adobe Air was never likely to be compiled to run on the ONEt, the MPU isn't anywhere near the minimal specification.   

There is always a qualification in the T&C that allows the specification to change.  Replacing the inverter + CCFL, with LED illumination, probably now saves a few pounds.    Once the required LED driver chips became available as a miniaturised hybrid ASIC for mobile phones with million plus production runs, it would make sense to change.  Because apart from the cost saving,  miniaturising the inverter, that was already small for say a 15"  laptop but still requires the same voltages for a 7" display, makes the heat generated a bigger problem - there's less metal in the components to spread the heat.

New ONEts may have LED illuminated LCDs - I don't know whether they do or not.   

« Last Edit: May 10, 2009, 05:06:58 PM by oldgrumpyman »

davemoore

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Re: Power taken during Fn + ZZZ mode
« Reply #8 on: June 01, 2009, 03:14:15 PM »
Hi all
Just to add my tuppence to this. This screen is indeed lit by LED's and not a ccfd as has been mentioned. i can ber absolutely certain of this as I have just spent a loooong time sourcing a replacement screen for my sons broken one! Found one eventually but cost me (him!) £50! Anyway the heatsource is in fact a usb "stick" wifi adaptor (sans case) mounted there and connected to the main board by 4 wires (as in USB!) this stick has an external rod aerial attached to it which is then stuck (with double sided tape) along the top of the screen! But as you say if it gets hot it's using energy!

Dave

oldgrumpyman

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Re: Power taken during Fn + ZZZ mode
« Reply #9 on: June 01, 2009, 10:19:08 PM »
Hi all
Just to add my tuppence to this. This screen is indeed lit by LED's and not a ccfd as has been mentioned. i can ber absolutely certain of this as I have just spent a loooong time sourcing a replacement screen for my sons broken one! Found one eventually but cost me (him!) £50! Anyway the heatsource is in fact a usb "stick" wifi adaptor (sans case) mounted there and connected to the main board by 4 wires (as in USB!) this stick has an external rod aerial attached to it which is then stuck (with double sided tape) along the top of the screen! But as you say if it gets hot it's using energy!

Dave

Thanks Dave for this confirmation about the current screen.

I was in a Maplin shop last week for a repair component and noticed a "refurbished" Onet on display.
It looked different, and I asked to have a look at it. 

The one I got in September last year had no Elonex Logo underlined by red squares underneath the screen, so it was different.  But it was the screen display itself that had caught my attention, one of those out the corner of my eye things, that I only noticed because of the difference, that I  knew somehow looked different. 

The LCD viewing angles on a CCFL backlit display are limited, but with a LED netbook screen they are almost unlimited. This one was near unlimited, and therefore it seemed to me that it almost certainly was LED illuminated, but there was still a hot spot near to the display that shouldn't be there for driving a LED display.   There was only one reasonable alternative, and I disconnected the WiFi, and went back to inspect it about ten minutes later, when the hot spot had gone.   Switching off the WiFi on my original Onet did not have that effect, although that may have been because they had either not implemented it or I had one with a faulty switch.   The current model Onet is not the same as the ones first shipped.

September/October last year, Elonex support was from an Indian call centre, and I had more than one of the support staff thanking me because "we didn't know that Sir, thank you, I will pass that on to my colleagues".
One of my questions was about the failure to better shut down power use during sleep mode, that I thought was an available function on the chips, such as for the WiFi, and although they said they would note this and pass it on, my cynicism about the effectiveness of Indian call centres knows no bounds. 

The WiFi failure on my original Onet, required that replacement under warranty was by me, but I passed on the package with the replacement unopened.   After my Maplin experience, I asked the new owner to turn off the WifI in sleep and standby mode, to see whether the hot spot disappears, and it does.  With the WiFi off, and after an automatic screen power down from lack of use,  restarting the screen display is immediate, which is consistent with a LED display as the first poster enquired.    I only found this out yesterday.

If you are buying a Onet on ebay (because Elonex shop has no Onet in stock) best not get one without the Elonex logo on the screen bevel.

And the answer to avoiding sleep power drain for a LED Onet, is almost certainly to disconnect the WiFi before putting it to sleep.