* Who's Online

  • Dot Guests: 17
  • Dot Hidden: 0
  • Dot Users: 1
  • Dot Users Online:

* Recent Topics/Posts

Wolverine's F16 Block 52 by Wolverine
[October 22, 2014, 05:26:30 PM]

Jay-el - lights by Peten
[October 22, 2014, 04:42:36 PM]

eBay heads-up by biggles
[October 22, 2014, 03:26:26 PM]

GROUP BUY for Toggle Switch RUBBER CAPS (2014) by biggles
[October 22, 2014, 03:25:35 PM]

Painting your pit! by sagrzmnky
[October 21, 2014, 06:48:16 PM]

Biggles Wishlist by biggles
[October 21, 2014, 06:00:47 PM]

LG Panel by biggles
[October 21, 2014, 05:29:11 PM]

FS weekend Lelystad 2014. by ulti
[October 21, 2014, 03:12:26 PM]

JJ F16 Block 52 Pit progress by Rufus
[October 20, 2014, 11:28:27 PM]

bluc69 F16 Block 52 pit by JJ
[October 20, 2014, 06:05:14 PM]

D-Sub Pin out Question by Doc_
[October 20, 2014, 04:26:19 PM]

JJ New wishlist by JJ
[October 20, 2014, 12:37:24 PM]

Pitmeeting Twente 2015 by JJ
[October 20, 2014, 06:11:43 AM]

HUD Replica by sagrzmnky
[October 19, 2014, 10:22:14 PM]

MailMan's Pit by JJ
[October 19, 2014, 06:31:41 PM]

KK's Pit by JJ
[October 19, 2014, 06:26:17 PM]

Clock by Rufus
[October 19, 2014, 02:49:11 PM]

Uri's Pit by trace
[October 19, 2014, 11:40:36 AM]

Parts 3D Models by Hempstead
[October 19, 2014, 04:49:21 AM]

Pitmeeting Twente 2014 by JJ
[October 18, 2014, 04:18:39 PM]

Author Topic: Negative voltage at AIC backlight?  (Read 2874 times)

Offline Rufus

  • General
  • ******
  • Join Date: Feb 2012
  • Location: California
  • Posts: 1501
  • Country: us
Re: Negative voltage at AIC backlight?
« Reply #60 on: December 23, 2013, 02:11:22 AM »
Ok...I think I've noodled something out about the Mean Well supply.  I went back and looked at the block diagram again, and it appears that while the G/G (COM, in the diagram) and mains earth may not be directly tied together they are internally shared somehow - with with a capacitor between the high side and mains earth presumably to create some delay/over voltage protection for given channels.  But it looks as if the circuit branches are self-draining at shut down, so nothing to worry about there.

I'm thinking though that I shouldn't ground my pit structure to/through the supply earth though, because a back EMF could harm the protective capacitors...but that I can use the wall plug ground over a separate cord with only the ground wire connected?  I'd lift this circuit with a relay at MAIN POWER - other than OFF, maybe with a slight delay.
- Rufus

Offline Cupra

  • General
  • ******
  • Join Date: Jun 2009
  • Location: Solothurn
  • Posts: 774
  • Country: ch
    • 1st VFW "Glory Wings"
Re: Negative voltage at AIC backlight?
« Reply #61 on: December 23, 2013, 02:17:28 AM »
Oops, that has gone under... or how ever you say  :harhar:

Yes, everything else is working without anny issues. Boards are dedected and at the power supply Pins of the boards the +12V DC is stable with the Switch on and it is 0,00 when the Switch is off.
The exact same circuit (a second one) is connectet to the backlight-connectors and there I have the -14V when i Switch off. But bowth funktions are working without problems or thermal abnormalities.
So for me I would say if eveything works proper there is no Need to do anything... I am just always a litte afraid if I have voltages I canīt explain  :notes: