Changing RAM in Deep Sleep?

[scottgroovez]

Can you youtube your shut down process. This I've gotta see!

 

[mooblie]

... and a car battery ... not to mention it is AC....

Ho, really? Some pretty unique cars where you come from, buddy...

 

[Phil A.]

Voltage is the least of your worries, it is amperage that kills, and a car battery has more than enough to fry someone many times over, not to mention it is AC which burns more severely and deeper than DC.

Firstly, car batteries are definitely DC.

Secondly, AC Doesn't burn more severely: The reason it's more dangerous is because the alternating voltage causes repeated muscle contractions which can make letting go of the source more difficult, whereas DC produces a single muscle contraction.

Finally, whilst it's true that it's current rather than voltage that kills, you have to take into account ohm's law (I=V/R where I=Current, V=Voltage and R = Resistance). 60-100ma (approx) can be a fatal current. You then have to consider skin resistance to find out how much current will flow: Wet skin has a resistance of approximately 1,000 ohms, dry skin around 1,000,000 ohms and broken skin can have a resistance as low as 500 ohms.

Even taking the worse case scenario of broken skin, the current you'll get from a 12v car battery is only 12/500 or approximately 24 ma, which is nowhere near enough to kill you.

The final thing you have to consider is the path through the body: Just touching any live connection of any voltage is harmless if you are completely insulated from ground (which is why birds can sit on high tension voltage lines without frying) - you need a potential difference for a current to flow. This can be between two terminals of a battery i.e. touch both), or between a voltage source and ground

 

[chrono1081]

Omg I can't believe people are arguing this!!!

OP SHUT DOWN the computer for sure. Deep sleep is not the same as shutting it down. You can permanently break a computer by changing its RAM while it is hibernating. Trust me, I did it several times. (It was to laptops with damaged LCD screens so I wasn't breaking good computers).

Oh and not to mention its a GREAT way to ruin the RAM.

 

[S.B.G]

Wrong.
You should always have your computer connected to the wall when replacing parts reason is that you may have noticed some wall plugs have 2 prongs but computers always have 3 the reason is the third one is the earth so if you disconnect the earth then the static in the case cant discharge and you can fry your motherboard. That does however cover computers with three prongs most laptops dont have three prong connects (including the MBP) so for the MBP you should touch a piece of steel in the case before doing anything else to make sure you discharge the static, it is also a good idea to leave the computer for say 5 minutes to allow the capacitors to discharge. This of course just a precautionary measure to make sure you dont break your 1K plus laptop.

Uh huh, ok...

In this iFixit guide, as an example what is proper, you will notice that the MagSafe adapter is not connected.

Installing MacBook Pro 15" Unibody Mid 2010 RAM

From Apple:
MacBook Pro: How to remove or install memory

Step 1: Remove the bottom case

Shut down your MacBook Pro. Disconnect the power adapter, Ethernet cable, USB cables, security lock, and any other cables connected to the MacBook Pro to prevent damaging the computer.

 

[squeakr]

Ho, really? Some pretty unique cars where you come from, buddy...

Wow, it was late when I typed that. Good catch. disregard the last, got those 2 switched, something you never want to do for sure. It should have DC and AC switched in that statement.

 

[squeakr]

Firstly, car batteries are definitely DC.

Secondly, AC Doesn't burn more severely: The reason it's more dangerous is because the alternating voltage causes repeated muscle contractions which can make letting go of the source more difficult, whereas DC produces a single muscle contraction.

Finally, whilst it's true that it's current rather than voltage that kills, you have to take into account ohm's law (I=V/R where I=Current, V=Voltage and R = Resistance). 60-100ma (approx) can be a fatal current. You then have to consider skin resistance to find out how much current will flow: Wet skin has a resistance of approximately 1,000 ohms, dry skin around 1,000,000 ohms and broken skin can have a resistance as low as 500 ohms.

Even taking the worse case scenario of broken skin, the current you'll get from a 12v car battery is only 12/500 or approximately 24 ma, which is nowhere near enough to kill you.

The final thing you have to consider is the path through the body: Just touching any live connection of any voltage is harmless if you are completely insulated from ground (which is why birds can sit on high tension voltage lines without frying) - you need a potential difference for a current to flow. This can be between two terminals of a battery i.e. touch both), or between a voltage source and ground

Sorry it was late and the statements were all supposed to apply to DC. I have edited the original to read correctly. I do know the difference and can't believe that I made the stupid typing error that causes my statements to become deadly possibly. DC burns go deep within the skin and muscle tissue whereas AC tend to remain closer to the surface due to the current nature. The alternating current gives times that allow for one to break free due to the alternating cycle, whereas DC locks the individual to the source (if you are lucky). Believe me as I have been shocked by everything from 1-2 V DC to 440 AC several times (and I don't enjoy it). But I have seen and known people killed and severely maimed (think arms and legs blown off and/or huge holes burnt into them) throughout my years (granted this was 100KEV DC, but not a pretty sight or smell). Before you think it is because I am negligent, it is because that was what I did for a living, electronics repair. Perfectly functioning machines that have gone bad and caused these injuries and yes even deaths that it became my job to return to specified operating ranges once again. Not s comforting thought that you have to work on a system that has just hurt someone so severely.