Author Topic: DLA Active Hub Failure  (Read 2909 times)

Offline mkozik1

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Re: DLA Active Hub Failure
« Reply #15 on: January 09, 2017, 08:59:33 PM »
OK - Some even odder thing has occurred tonight.  I plugged in the 12v power supply to provide a video for Corey showing the power supply still showing voltage but the power LED fading away, however, that was not the case for tonight.  The power LED has remained on tonight (have not moved it from my PCB clamps) and I am able to read the same voltages I am reading on the other board (without the option) with the PC power supply connected.  The weird thing is I am not reading 5v anywhere.  Even more weird is the fact that when I check the pins on the 4-pin PC connectors with the option, I am seeing 12v and 3.3v NOT 5v.  I checked the PIC and it is matching the other board.  I tested the 5v regulator and it is not outputting anything but my question is what is it really there for?  I will replace it but just trying to understand!
- Mark

Offline corey872

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Re: DLA Active Hub Failure
« Reply #16 on: January 09, 2017, 09:29:20 PM »
... I plugged in the 12v power supply ... The power LED has remained on tonigh...

This is the 'original power supply' (which I'm guessing is just a 12V brick? ... or the later 'PC' power supply?

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... I am able to read the same voltages I am reading on the other board (without the option) with the PC power supply connected.   The weird thing is I am not reading 5v anywhere.

Anywhere on either board?  Anywhere on the 'burned' board?

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  Even more weird is the fact that when I check the pins on the 4-pin PC connectors with the option, I am seeing 12v and 3.3v NOT 5v.

Possibly the 5V regulator has finally died and left an open circuit.  With power disconnected, you could look for continuity between the pin of the 5V and the pin of the PC connectors.  This would insure there is no cold solder joint.

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I checked the PIC and it is matching the other board.

PIC voltage?  3.3V, I believe.

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I tested the 5v regulator and it is not outputting anything but my question is what is it really there for?  I will replace it but just trying to understand!

The 485 chips need a 5V input, PIC is 3.3 and 12V to the nodes.
Corey
 2018 uSC, Afterburner, uAmp co-op - pending May-June 2018.  Remaining boards are now FOR SALE

 

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