« previous next »
Pages: [1]   Go Down

12V trigger question

0 Members and 1 Guest are viewing this topic. Read 1942 times.

glynnw

  • Full Member
  • Posts: 991
  • I have tin ears.
12V trigger question
« on: 6 Jun 2016, 12:33 am »
After simply changing some rca connectors on my preamp, the 12V trigger seems to work in reverse, turning everything on when I turn the preamp off.  Does the trigger put out a 12V signal when unit is turned on or does it cease to put out a 12V signal when preamp is turned on?  Mine is putting out 12V at the trigger when preamp is turned off and ceasing to supply 12V when preamp is turned on.
Logged

glynnw

  • Full Member
  • Posts: 991
  • I have tin ears.
Re: 12V trigger question
« Reply #1 on: 6 Jun 2016, 07:02 pm »
OK - a good night's sleep and I try again.  Same result.  When I test the voltage on the main board at the power attachment terminal I get the following with unit powered but turned off:  12v - 12.13V   5v - 4.97  12T - 12.12 - when I turn the unit on the 12T goes to 0.  Is this normal?  I have always assumed that the trigger supplied 12V when on, not when off.
Logged

tortugaranger

  • Facilitator
  • Posts: 1752
  • Innovated passive & active preamp technology
    • Tortuga Audio
Re: 12V trigger question
« Reply #2 on: 14 Jun 2016, 02:57 pm »
Quote from: glynnw on  6 Jun 2016, 07:02 pm
OK - a good night's sleep and I try again.  Same result.  When I test the voltage on the main board at the power attachment terminal I get the following with unit powered but turned off:  12v - 12.13V   5v - 4.97  12T - 12.12 - when I turn the unit on the 12T goes to 0.  Is this normal?  I have always assumed that the trigger supplied 12V when on, not when off.

Hi Glynn,

Just saw this note. No, that's not normal. Is that happening with your kit or one of your boards?

Morten
Logged

glynnw

  • Full Member
  • Posts: 991
  • I have tin ears.
Re: 12V trigger question
« Reply #3 on: 14 Jun 2016, 06:43 pm »
On one of the boards - an LDR3X-V2.1.  While changing some of the RCA connectors I apparently pushed the positive and negative solder points on the trigger connector together.  Have fixed that, but now trigger is reversed.  Outputs 12V when off and nada when on.
Logged

tortugaranger

  • Facilitator
  • Posts: 1752
  • Innovated passive & active preamp technology
    • Tortuga Audio
Re: 12V trigger question
« Reply #4 on: 14 Jun 2016, 08:22 pm »
Quote from: glynnw on 14 Jun 2016, 06:43 pm
On one of the boards - an LDR3X-V2.1.  While changing some of the RCA connectors I apparently pushed the positive and negative solder points on the trigger connector together.  Have fixed that, but now trigger is reversed.  Outputs 12V when off and nada when on.

What I suspect happened is the PNP output mosfet shorted and was damaged. It's driven by an a NPN mosfet that appears to still be working. Normally we turn on the NPN with a high output which then pulls the PNP low to enable 12V Trigger. It appears the logic state has become reversed so its only seeing the NPN which when "on" turns the 12 V off.

I suppose I could send you a custom version of the firmware that has the 12V Trigger out logic reversed and see if that works. If not then probably you need to replace the 3 pin PNP mosfet which is Q5 on the board.
Logged

glynnw

  • Full Member
  • Posts: 991
  • I have tin ears.
Re: 12V trigger question
« Reply #5 on: 14 Jun 2016, 09:27 pm »
Don't worry about it.  I used the trigger to turn on a PS Audio Powerplant.  I am now just using the Powerplant's remote to trun it on/off.
Logged
Pages: [1]   Go Up
« previous next »