12V/7V switch behaving strangely

Oz · Post by Oz » Wed Oct 23, 2002 12:10 am

Hey there,

I followed the 12V/7V switch building guide to switch some fans between 12V and 7V. I've got 2 fans connected to it: a panaflo and a zalman. It works really well, but there's just one problem - sometimes when I switch from 12V to 7V, my screen goes black for an instant, and then re-appears! This only happens sometimes, and I've only noticed it going from 12V to 7V and not vice versa. Could this be causing the same kind of problem with harddrives/other devices, in which case it could be detrimental? I've not noticed any corrupted files or anything. Yet

. Any ideas?

Cheers,
Oz

quokked · Post by **quokked** » Wed Oct 23, 2002 12:46 am

hmmm... that is odd... could be a few things if your computer isn't totally dieing on u... could be your video card cutting out and coming back into it causing the screen blanking....
ummm this is a very odd thing though, I'd try to switch to another fan quietening method like a baybus or a rheostat to turn the fans down.

it would be determintal I think personally not good having your screen go crazy like that often

Post by **MikeC** » Wed Oct 23, 2002 12:56 am

If you built a 12/7V switch, it's not something we ever did an article about here. It IS possible to do -- even 12-7-5V is easy -- but the article here describes a 12/5V switch. The behavior you describe is odd; really tough to diagnose remotely...

Oz · Post by Oz » Wed Oct 23, 2002 6:14 am

Woops sorry, I meant a 12V-5V switch! It's quite odd really... It has only happened a handful of times as well. I think I'll pretend it never happened

Cheers,
Oz

quokked · Post by **quokked** » Wed Oct 23, 2002 6:19 pm

lol 12-5V maybe would mean that u've got sparking along the switch, all switches are not perfect u'll get what's called "bounce" , it kinda looks like squgggle and slowly get's smaller think of a boucing ball and the look that'd make, that might be what's causing it

TerryW · Post by **TerryW** » Tue Oct 29, 2002 5:16 pm

Hello,

Sorry for not responding to this thread B4 now. This problem could be the switch type.

When ordering switches you need to be carefull in the type of switch you request. Some are "make B4 break" and others are "break B4 make".

An easy understanding: "make B4 break" means the internal switch contacts "make" another connection, B4 they switch or "break" the first connection. Most "make B4 break" switches are rotary switches, used for audio applications.

Any switches to do with power supplies should be the "break B4 make" variety.

TerryW

quokked · Post by **quokked** » Tue Oct 29, 2002 5:39 pm

so the setup is "make or break" isn't it?

sorry couldn't resist

Oz · Post by Oz » Wed Oct 30, 2002 1:08 am

Ah ok thanks TerryW!