Old Book Teardown #3: Vest Pocket Guide To Electrical Testing And Troubleshooting (1987)

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Silly Job Title: Charge Charmer

This video is part of the Old Book feature of my video blog.

In this video we take a quick look at Vest Pocket Guide To Electrical Testing And Troubleshooting by John E. Traister published in 1987 with 130 pages.

In the video I also wish everyone a happy new year, talk a little about upcoming Xin1 projects, and mention how expensive it will be to upgrade my scope to 350 MHz.

And if you’re interested the Wikipedia page for Logic Analyzer says that the first commercially available instrument to be called a “Logic Analyzer” was the HP 5000A Logic Analyzer, introduced in October 1973.

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Victorinox Swiss Champ Red Swiss Army KnifeThis is an image of the product.notes

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How to Remove Old and Useless Drivers in Windows

I had a problem where I needed to delete a device driver that had been installed so that I could install a replacement. I found How to Remove Old and Useless Drivers in Windows and the process was roughly:

  • Win + X: Windows PowerShell (Admin)
  • SET DEVMGR_SHOW_NONPRESENT_DEVICES=1
  • Win + X: Device Manager
  • View -> Show hidden devices

You can then look for the old driver and remove it.

BIOS settings for ‘verve’

I went hunting in the BIOS for ‘verve‘ which has a ASUS PRIME B550M-A motherboard and I found I needed to change two settings.

The first setting was Advanced -> CPU Configuration -> SVM Mode = Enabled. This enables AMD-V and allows the CPU to function in a hypervisor.

The second setting was Advanced -> Onboard Devices Configuration -> USB power delivery in Soft Off state (SS) = Disabled. This fixes the problem with the power button not working as discussed here: Earth leakage hack.

Running notepad.exe as Administrator

Man, back on Windows for my new studio computer ‘verve‘. Needed to figure out how to edit C:\Windows\System32\drivers\etc\hosts and that was certainly more difficult than it needed to be.

In the end I used “Method 3” over here to add an “Open in Notepad (Admin)” item to my shell context menu:

  • Open regedit
  • Navigate to: HKEY_CLASSES_ROOT\*\shell
  • Add a new key ‘runas’ under ‘shell’
  • Change (Default) to: Open with Notepad (Admin)
  • Add a new key ‘command’ under ‘runas’
  • Change (Default) to: notepad %1

Earth leakage hack

Happy New Year! Best wishes to all my friends for 2024.

I have this weird problem with my new studio computer ‘verve‘. When I press the power button, it doesn’t turn on. It does have 15 USB cables plugged into it, and quite a number of those are powered, which seems to affect the system.

The power for most of the devices on my bench goes through a PowerShield Defender 1600VA UPS battery, and then through an Arlec PB91 Residual Current Device (RCD).

The RCD has a test feature so you can press the button on the RCD and it will trip the safety which will disconnect the power. If I do this most of the equipment on my bench will turn off (but, importantly, not my workstation ‘verve’) including all the powered USB devices which are interfering with my computer.

After I trip the RCD I can power on my computer, and then once it’s powered on I can reset the RCD and bench power is restored. It’s a bit fiddly but at least it works!

Setting Konsole title to $USER@$HOSTNAME

First: Settings -> Configure Konsole -> General -> Show window title on the titlebar (checked)

Then: System -> Configure Konsole -> Profiles -> [Default] -> Edit… -> Tabs:

  • Tab title format: %w
  • Remote table title format: %w

Then you need this config and these two shell functions in your .bashrc:

# 2023-12-29 jj5 - if not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

# 2023-12-29 jj5 - set the Konsole window title
echo -ne "\033]2;$USER@$HOSTNAME\007" >&2

# 2023-12-29 jj5 - intercept ssh and sudo commands to reset window title on exit:
ssh() {
    /usr/bin/ssh "$@"
    echo -ne "\033]2;$USER@$HOSTNAME\007" >&2
}
sudo() {
    /usr/bin/sudo "$@"
    echo -ne "\033]2;$USER@$HOSTNAME\007" >&2
}

Transferring large files with Salt file.managed

Well, this took me a few hours to figure out.

If you’re going to be transferring large files using file.managed in your salt state, make sure you specify show_changes: False, otherwise salt will start trying to boil the ocean and calculate the unified diff of your enormous files.

The clue that this is the problem you're having is if one of your CPU cores pegs at 100% and your state doesn't apply in a reasonable amount of time (minutes, I guess).

Also you probably want to make sure you're not trying to use your large file as any sort of template. By default file.managed will assume no template, which is what you want for large files that aren't templates. I've never used large files which are templates, but I suspect if you tried that you'd have a bad time.