Turing Mk II Rev 5 - not working after wrong voltage applied

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sndmsc
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Turing Mk II Rev 5 - not working after wrong voltage applied

Post by sndmsc » Wed Feb 17, 2021 9:52 am

I connected the wrong PSU to my Intellijel 7u performance case - 12V DC (1.5A) rather than the 15V-18V PSU that came with the rack.

When I connected the correct PSU nothing powered up. For a second I thought I'd blown something in the power strip inside the rack.
But I disconnected all the modules and reconnected them one by one until I figured out that the Turning Machine Mk II was causing the 12V led on the power strip inside the rack to trip out.

I pulled the back PCB off the TurnIng Machine but there's no obvious damage to any of the components.

So I'm wondering if anyone has any advice as to which one might have burnt out? I'd like to get a replacement part so I can get it up and running again.
I have a voltmeter so I can measure voltages if anyone can describe what I should be looking for.

Thanks in advance!

PacificState
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Re: Turing Mk II Rev 5 - not working after wrong voltage applied

Post by PacificState » Wed Feb 17, 2021 10:10 am

There's a leading dash there, but to confirm - you connected +12V DC (or at, least - a 12V power supply with the same polarity as the 15-18V DC power supply)? I've never seen a lower voltage power supply cause damage, but someone around here might be wiser than me. So it sounds like:

- The other modules *are* working, so the case's 12V power rail is intact

- Connecting the Turing machine kills off the 12V LED

?

If so, it sounds like a shorted component in the module, but it's not what I'd expect to have happened from what you did. I'd start by checking with your meter to see if any of the +12/+5/-12V input pins on the module's power header are shorted to ground.

sndmsc
Learning to Wiggle
Posts: 21
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Location: Dublin, Ireland

Re: Turing Mk II Rev 5 - not working after wrong voltage applied

Post by sndmsc » Wed Feb 17, 2021 10:43 am

PacificState wrote:
Wed Feb 17, 2021 10:10 am
There's a leading dash there, but to confirm - you connected +12V DC (or at, least - a 12V power supply with the same polarity as the 15-18V DC power supply)? I've never seen a lower voltage power supply cause damage, but someone around here might be wiser than me. So it sounds like:

- The other modules *are* working, so the case's 12V power rail is intact

- Connecting the Turing machine kills off the 12V LED

?

If so, it sounds like a shorted component in the module, but it's not what I'd expect to have happened from what you did. I'd start by checking with your meter to see if any of the +12/+5/-12V input pins on the module's power header are shorted to ground.
All you assume is correct. The PSU was the same polarity but just with a lower voltage. The other modules are all working. And connecting the Turing Machine kills the 12V led.

I just metered them out and there's no short between gnd and either the + or - pins.

I've just reassembled it and plugged it back into the rack on a different power connector and now it works! Very strange.

Thanks for your reply.

PacificState
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Posts: 114
Joined: Wed May 01, 2013 10:19 am

Re: Turing Mk II Rev 5 - not working after wrong voltage applied

Post by PacificState » Wed Feb 17, 2021 3:59 pm

Great! My hot take would be that there was a blob of solder or wire left over from the Turing build that got dislodged - if you open it up again, just check to see if anything is rattling around in the case.

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synthetek
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Re: Turing Mk II Rev 5 - not working after wrong voltage applied

Post by synthetek » Thu Feb 18, 2021 7:45 pm

Maybe a polyfuse tripped on the Turing Machine and then after unplugging it for a while it reset itself.

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