Category Archives: Simple Repairs

Fixing GoTenna – fast blinking LED (can’t pair) issue

Author page that take all credit for resolving issue:

http://www.pingturtle.com/home/post/gotenna-firmware-failed-fix-white-led

Local copy of PingTurtle article + data

Local Hard Copy
Local firmware files copy
Tagged , ,

dosdude1, Homebrew, Node (and lot of other applications) throwing illegal hardware instruction on patched Catalina (installed on incompatible machine)

Yesterday I decided to give a try in making my old 7.1 MacBook Pro second chance by upgrading macOS to Catalina with IS NOT supported by Apple.

There is a reason why they want drop support for older architecture but You can squeeze last breath if You can allow for sacrifice in stability or compatibility. Upfront I can say that iMovie crash and I was unable to resolve that issue, other applications used for basic web-dev (phpstorm, mysql, nginx, npm) looks and feel working good but still I would not recommend it for profesional work when disruption in workflow cause money or data loss – for any non critical applications, reading email, watching YT it’s worth of trying.

First step is to upgrade patched macOS dosdude1

When You got Your system set up, and try to execute applications installed with Homebrew (in my case it was node) I got this error:

illegal hardware instruction

After investigation, I was able to locate problem. Applications distributed in Homebrew as bottle are compiled for specified architecture. Authors of Homebrew have valid reason to assume that this compiled software is going to be executed on compatible hardware in correlation with macOS version. There is no change of having C2D CPU in Catalina, here is why compiled code is targeted for newer CPU.

Lucky Homebrew have ability for self compiling any packages, but that operation have exactly same (error) outcome as when installing compiled bottle.

answer to this problem, is in telling Homebrew to set target architecture for older CPU-s.

You can edit this file:

nano /usr/local/Homebrew/Library/Homebrew/extend/os/mac/hardware.rb

and change it’s content to

frozen_string_literal: true
module Hardware
def self.oldest_cpu(version = MacOS.version)
if version >= :mojave
:core2
else
generic_oldest_cpu
end
end
end

Notice edited architecture, when OS is greater or equal to Mojave

After that change we can recompile from source our not working applications by using following command.

brew reinstall -s python

-s stands from source

When trying recompile node, I still got error. After more investigation i found out that Node depend on another packages, that are already installed but not recompiled with new directive. Dirty solution i found is to see what node depend on:

brew info npm

and from following code, read dependencies section to recompile all dependent packages with -s

brew reinstall -s pkg-config
brew reinstall -s icu4c
brew reinstall -s python

After that, we can reinstall node

brew reinstall -s npm

After this operation, node works perfect. You can follow same schematic for any other applications that can be found in Homebrew.

Why it’s important to have oscilloscope and not always rely on multimeter measurement.

Here I post couple pictures of me, fixing LED WALL CLOCK.

There are spikes caused by (DC-DC converter) capacitor that failed (open, lost capacitance, high ESR) and they lead to RTC / MCU freeze and cause undesired operation.

On pictures there is waveform with failed capacitor (notice spikes) and after replacement.

Video:

Good looking capacitor turn’s BAD – why it’s good to have ESR meter

Here i’m working on Dymo PSU that failed, i most like expect leaked capacitor – but everything looks fine… for my eye… but not for ESR meter… we find a open (dead) cap that looks perfectly good and would never expect me to believe it was cause problem!

Also here is my video

How RIP VideoCD disc on linux and play it back on device without cdrom

I have lot of movies on VideoCD that i bought just to have in my collection and are still fun to watch, but DVD drive on my laptop computer many years ago was switched to second HDD caddy. Only way to play them is using external USB DVD drive with is problematic to carry around:) Is there option to easy “RIP” copy VideoCD disc into video file for easy playback?

Yes… on Ubuntu and many other distributions is easy as one command.

vcdxrip -C=/dev/sr0

where /dev/sr0 is our drive, in my case external USB drive
after running that command, we get extracted all .avi files that can be played from HDD using for example VLC player.

Zello sounding like DMR Motorola aka Talk Permit Tone

Here are two files that make Zello sound more like proper 2 way radio. ( Motorola Mototrbo )

One file is for beginning second for end transmission

Clansman PRC-350 (RT350) battery adapter mod for use rechargeable AA

Before and after applying mod