Re: PiRLP Suddenly Not Working


David Cameron - IRLP
 

Did you not see the solder splashed all over ic U4? There is your short! It looks cold - you should be able to just pick it off.

David Cameron 

-------- Original message --------
From: Russ Woodman <k5tux@...>
Date: 2/12/20 12:36 PM (GMT-08:00)
To: IRLP@irlp.groups.io
Subject: Re: [IRLP] PiRLP Suddenly Not Working

Pictures included. Note that this board was ordered PRE-modded for 3.3v. I did not do the mod myself.

On Wed, Feb 12, 2020 at 10:59 AM, David Cameron - IRLP wrote:
Under normal circumstances, with all LEDS lit, the board draws less than
80mA at 3.3V. Without any LEDs it is in the order of 2mA.

Can you take a picture of the mod you did to bring 3.3V? Maybe I will
see the issue. Both the top and bottom of the board.

There are lots of locations where a short could be in the board. A cold
joint would never cause a short, it would cause it to be open.
I would look more carefully at the GPIO cable as it is more suspect.

Also, check the resistance to ground from the 3.3V jumper to the board
ground.

The other thing to do is try to power on the system, and feel around the
chips on the IRLP board for something getting hot. Nothing should be
mildly warm.

Dave Cameron
VE7LTD

On 2020-02-12 09:55, Russ Woodman wrote:
Hi, Dave.

I am 100% sure the cable is connected correctly. It would appear that
the problem is on the IRLP board, not the Pi. I say this because if I
leave the ribbon cable connected and unsolder the 3.3v jumper mod on
the IRLP board, the Pi will boot fine. If I solder it back up again,
Pi doesn't boot. Is there someplace I can look on the IRLP board for a
short or cold solder or something? This was work in its exact
configuration 45 minutes before I powered it on the second time.

Russ


Links:
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[1] https://irlp.groups.io/g/IRLP/message/76813
[2] https://groups.io/mt/71210430/500965
[3] https://irlp.groups.io/g/IRLP/post
[4] https://irlp.groups.io/g/IRLP/editsub/500965
[5] https://irlp.groups.io/g/IRLP/leave/defanged

 

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