Power Molex On/Off

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NerdzRule7

Limp Gawd
Joined
Oct 3, 2002
Messages
244
alright.. i have an idea and i wanna ask you guys before i do it to make sure theres nothing i'm overlooking. i want to do a relitively simple mod, i have 2 harddrives in my server i use for backup, not storage. so those 2 drives are not connected to my ide and power cables very often. the problem is, when i do need to backup, i have to open up the server and reconnect everything. my thought was that i could just take a single molex line from the psu, and take every wire through a diff switch, so when i needed the drives i put all 4 switches on, when i didnt need them, i put all 4 switches off. i would of course have to shutdown before i flip the switches but thats no problem. so is there anything special i would have to do to the wires or can i just run them through a switch like i would anything else, and also, any good ideas on being able to turn on/off all 4 switches at once with a single switch?thanks-The_Nerd
 
Yes you can do this. But, you only need two switches for the hots or a switch that can handle multiple connection. I will find a link later.
 
Also, thanks to some experimenting at work today, you *should* be able to switch the drives off and on without shutting down. I personally think it's a horrible idea, but my cow-orkers proved me wrong today. With WindowsXP, the drives disappear when you pull the power to them, and show back up after powering back on (you have to scan for new hardware though).
 
wow... thats pretty cool..i didnt think you could do that but isnt there a risk of a short of some kind? that would especially be true in my case if i used 2 seperate switches for the power leads, if i powerd them up at different times i would imagine i could kill the drive?
 
Alright, This is what you do:

Turn Off PC
Enable both switches
Boot PC

When the pc is off no power is going to the hdds. Do not do this while the machine is running.......
 
lol yea i was kinda iffy on the flipping of the switches while the comp was on.. i think i have two switches left over from a few lighting mods and the like i did a while ago... i'll see what i can hash together and then report back with pics if possible.. keep any input coming as well as any electronic switches or hardware that might be of use.. thanks guys-the_nerd
 
I've got my doubts that an IDE bus will work, with an unpowered drive attached to it...
 
I'm a little iffy about it too :). Like I said, my cow-orkers are convinced that it's safe, but I'm not so sure.
 
Do it my half safe way.. standby mode
I dont think the ide will like it much either. Go with a external enclosure.
 
External enclosures are definately the way to go here. You get hotswap (with USB & firewire) and the ability to move them offsite.
 
yea, it'll work... but you only need two switches and put one in 5volt rail and one in 12v rail... you can leave the two grounds connected

as mentioned above... external enclosures are also a very good idea but it does cost some money, takes up some space, and a lil bit more of trouble but still good
 
You need a 4PST (4 pole, single throw) switch if you want both drives turned on and off at the same time or 2 DPST (2 pole, single throw) switches if you want to be able to turn each one on/off independently.

-special [k]
 
specialk said:
You need a 4PST (4 pole, single throw) switch if you want both drives turned on and off at the same time or 2 DPST (2 pole, single throw) switches if you want to be able to turn each one on/off independently.

-special [k]
Click to expand...


Uhm... You can use DPST for both. It's ok to feed both drives off the same +5V and +12V rails.
 
I'll re-iterate my "unpowered device on the IDE bus" concern. Take the hard drive you're using and plug it into the IDE bus with another drive, but don't plug the drive in. Make sure you can read the other drive.
 
2 pole switch is ok, but if you plan on turning them on while the pc is running you might want to take a multimeter and check for continuity between any of the poles while you slowly move the switches to on and off positions. Some of the cheap switches are actually gona bridge some of the poles as you move em from on off position.
 
wayne said:
he said "independently"
Click to expand...


There were two options. specialk said that if you wanted to switch both drives AT THE SAME TIME, you could use a 4pole-single throw switch. I said that you can use a double pole-single throw switch to do the same thing, because you can tie the power together. If you read the post I quoted when I made that comment, it should make sense.
 
a 2 pole switch for the yellow(12v) and red(5v) is all you need. DO NOT TURN ON OR TURN OFF WHILE THE PC IS RUNNING!!!!! IDE IS NOT HOT SWAP ABLE!
 
gee said:
I'll re-iterate my "unpowered device on the IDE bus" concern. Take the hard drive you're using and plug it into the IDE bus with another drive, but don't plug the drive in. Make sure you can read the other drive.
Click to expand...
I do this all the time. When I'm trouble shooting a computer and trying to figure out what is wrong - I'll try to remove everything possible from the mobo (leave cpu, ram, video card, mobo, and psu). I always just unplug the power molexes from the ide devices - instead of removing the ide cables. Never been a problem and I've been doing this for years.
 
You only need one DPST switch, leave the ground connected or ground to the case frame, but a removable rack would be the best idea
 
hook the hard drives up to the molex, cut the two black wires and put them togeather, and then hook those up to another wire (molex 2 wires, then one wire) hook that up to a switch, then the other end of the switch down to the two remaining wires thisway you alwase have the power on to all of them but the power cant go anyplace b/c there is no groung, the 5v and 12v wire can use the same ground, multible hard drives can use the same ground, you just need a switch that can handle the the power coming out but if you kill the ground connection, then the HD is off, if you connect the grounds you complete the cercet, and boom power is on
 
thanks for all your sugestions guys. i have put together a basic switch unit. it works like a charm even though its not the prettiest peice of engenering i've ever seen.. lol. as soon as i find a place i'll host the pics so u guys can see. its 2 single pole rocker switches. that was the easiest thing to do, cuz my local radio shack didnt have a decent 2 pole switch. so i used one rocker switch for each power line, and let the ground wires stay. i've been using the switch for about a week now with no problems. when i need my backup drives, i shutdown, flip both switches, and boot back up. when i'm done, i shutdown, flip them back, and boot up again. my friends have no idea what use i'd ever get out of a switch like that but honestly i love it. it saves me the trouble of having to pull my computer out of the corner and having to open it up, get around and plug back in the drive. its simple, fast, and it works. thanks for your help.. i'll get some pics asap so you can see how everything turned out!-The_Nerd
 
NerdzRule7 said:
thanks for all your sugestions guys. i have put together a basic switch unit. it works like a charm even though its not the prettiest peice of engenering i've ever seen.. lol. as soon as i find a place i'll host the pics so u guys can see. its 2 single pole rocker switches. that was the easiest thing to do, cuz my local radio shack didnt have a decent 2 pole switch. so i used one rocker switch for each power line, and let the ground wires stay. i've been using the switch for about a week now with no problems. when i need my backup drives, i shutdown, flip both switches, and boot back up. when i'm done, i shutdown, flip them back, and boot up again. my friends have no idea what use i'd ever get out of a switch like that but honestly i love it. it saves me the trouble of having to pull my computer out of the corner and having to open it up, get around and plug back in the drive. its simple, fast, and it works. thanks for your help.. i'll get some pics asap so you can see how everything turned out!-The_Nerd
Click to expand...
courtesy of Flecom
http://www.flecom.net/[H]OCP/upload.html
 
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