Tektronix’s TDS/DPO7000 series Mechanical (Chassis) Design is Evil

I thought the TDS500~800 series design is already frustrating to service. But TDS7140 (or DPO7000) takes the cake. Whoever the a**hole designed the chassis made it a f*cking lettuce wrap. It’s not even an onion that you can predictably guess how you’d approach it.

To get any meaningful access to the insides, you MUST first remove the plastic front panel bezel, which is a fragile part that if you didn’t get the plastic hooks right, you’ll break it when you try to force anything. The service manual is not helpful. Likely written by somebody with a ‘fuck it. somebody’ll figure it out’ attitude.

This can be seen by the service manual giving an exploded view diagram without a precise order-of-removal dependency graph, nor the decency of telling you where each hook is and which of them are slides that must not be pried open like hooks. This is basically is tricking people to break the front bezel because those who didn’t know this already won’t know until they shine a flashlight to investigate the geometry around the hooks before releasing the front bezel.

It’ll make much more sense if you see the insides of the released front trim/bezel:

Not to mention that that black (lower) Acq front panel trim was double-sided taped to the BNC panel because it’s so easy to f*ck up the plastic to get access to the insides of the unit. The bottom trim is supposed to come out first (because there are no hooks) but I wiggled the upper part out first, luckily without damaging the bottom hooks, because of the silly double-sided tape used for the lower trim.

None of these shit was mentioned in the service manual. It basically said “there are some hooks in the front panel, pry them open and pull it out. Good luck!”. Mixed with a flimsy, non-intuitive chassis design, it’s pretty much telling outsider to break the front trim.

I really couldn’t believe some f*cker who’s a delight to deal with would design a case with an insane order of disassembly so I read the vaguely worded manual over and over again to see if there’s a step I can skip to get partial access to the PC motherboard inside. I couldn’t find any so I gave up and follow the painful disassembly order and realize the design was indeed evil and fully intended to shove it up the a$s of whoever that tried to repair the unit.

The service manual is also very unhelpful that they first told you to remove all the knobs yet the rest doesn’t depend on it. The real first step is to remove the front plastic trims. Nonetheless you need to remove the carrying handle because it’s bolted to the right side of the sheet metal.

The take away is that the Mushu-chicken lettuce wrap is that the top and left side is one sheet metal, while the right and bottom side is another sheet metal in one straight piece. What’s really frustrating is that you cannot just move the top-n-left half cover in isolation because it’s sandwiched by the right-n-bottom half cover, which in turn it’s bolted down by the screws that are obscured by the front trim:

This is madness!

HP/Agilent/Keysight doesn’t do this kind of abusive design that reeks evil. I should start charging more if people sends me a Tektronix to fix if I have to deal with the damned disassembly maze.

Another bit that shows whoever wrote this damned service manual doesn’t give a shit is the instruction to take out the 2-in-1 CD+HDD bracket. A normal person who dealt with Agilent Infiniium unit would expect the 2-in-1 bracket should come out on its own in one piece. This is not the case for this damned Tektronix scope.

Here is all the information available from Tek on how to do it (which is both incomplete, misleading and confusing):

Should not have used the word slide. Should use the word pull because the HDD+CD combo bracket is trapped in the unit so there’s only one way to get it out: by pulling. You can’t slide it from the sides as the sides or the top of the CD drive bracket are covered.

Figure 6–20 is just an exploded diagram, which covers everything taken apart without explaining the order and dependencies, which is essential because this damn thing was designed in a way that you wouldn’t have intuitively guessed the order by just looking at it.

Turns out after you removed all the screws that seemed relevant, the HDD+CD combo bracket won’t come out because it

The manual is surely misleading because if you just need to take the HDD+CD combo bracket out, you don’t need to take out the 4 #0 Philips screws. This is something you can do after you pulled the CD drive bracket out, but first you have the remove the two T-15 at the front of the CD bracket, which made it look like it was the bracket of the HDD+CD bracket combo, so you wouldn’t suspect the whole thing hinges on you pulling the CD drive bracket out first.

Tektronix certainly doesn’t have good excuses for these lame design with lousy documentation. Even with cost savings in manufacturing materials, it just doesn’t justify the labor. This is just taking shortcuts in design and it shows the lack of forethoughts and purely poor judgement.


This scope is lame everywhere. It really showed the people designed it either divided it into too many teams or they simply doesn’t give a shit. There’s no reasonable excuse for this other than laziness. The hard drive interface was converted twice! It takes an IDE drive, converts it to an SATA drive, then plugs into a board that converts the SATA to IDE back again just to fit the form factor.

Not to mention that the 44-pin to SATA adapter is a ribbon inside the caddy, which means it’s not carefully designed that you can slide the drive in. You have to pull the short cable out to plug it into the drive and push the bulk back in. It’s easy to mess the ribbon cables up with this design. It just screams the people who designed it hate their job.

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All in 1 Mini Card Reader Manufacturing Flaw (Bad USB connector)

Recently, I’ve bought this CF card reader on eBay but it doesn’t detect at all.

Picture 4 of 7

I looked closely into the connector with a loupe and realized that the mini USB conductor was molded incorrectly. The center middle pin was pushed down because extra plastic was deposited above it:

The seller refunded in full but I figured that if the connector is malformed at the molding stage, buying it from another seller is not going to make it work, and the other form factors/connector configurations are inconvenient, so I tried my luck and see if there are exact matches for the connector they’ve used. Turns out it’s a 56 cents connector (price for 1 piece) available in Mouser (UJ2-MBH-1-SMT-TR):

In bulk, this connector can be bought for $0.22. For something that’s selling for $5/pc, the Red Chinese manufacturing had to go cheap to shave a few cents that ended up turning finished products into total trash. Most people are not electronics/troubleshooting savvy enough to figure out this shit, and the labor cracking the piece up and the SMD rework can easily buy 20pcs new. I just happened to have the tools (Metcal hot tweezers) so I can desolder the bad connector in seconds, but average users do not have that luxury so the neutered USB card readers go straight into trash.

We need more products NOT made in China!

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Getting Quickbooks Pro 2019 to work on Windows 10 21H2

Turns out there’s two hurdles to launching Quickbooks as they used some old Windows dependencies

  1. Internet Explorer needed for DLL/ActiveX/DCOM
  2. XPS Writer needed for PDF libraries

In later versions of Windows 10, IE11 was turned off by default, and 21H2 made it difficult to re-enable it by hiding it from Windows’s (optional) features checkboxes, so it needs to be enabled through command line.

If you do not enable Microsoft’s XPS Writer feature, you’ll get this error message about PDF on start, though XPS is Microsoft challenger to PDF so they are not the same thing

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Internet Explorer 11 on Windows 10 21H2

Microsoft has disabled Internet Explorer on later versions of Windows 10 as they really want people to use Microsoft Edge. However, disabling Internet Explorer 11 might break some software such as Quickbooks 2019, which relied on old fashioned DLLs.

Since 21H2, Microsoft went the extra mile preventing users from re-enabling Internet Explorer 11 by hiding it from GUI ways to turn Windows features on or off (whether you use the app mode interface or the classic optionalfeature.exe interface launchable from control panel’s “Programs and Features”). Instead this needs to be enabled from the command line

https://learn.microsoft.com/en-us/troubleshoot/developer/browsers/installation/disable-internet-explorer-windows

dism /online /Add-Capability /CapabilityName:Browser.InternetExplorer~~~~0.0.11.0.

or

dism /online /Enable-Feature /FeatureName:Internet-Explorer-Optional-amd64.

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Maildroid does not save sent email to IMAP ‘Sent’ folder by default

This behavior is so frustrating. We don’t live in a time where IMAP storage space is at a premium anymore! Fairmail saves a copy of sent mail in the IMAP’s ‘Sent’ folder by default.

I did some research and it seems like MailDroid insists on ‘saving the sent mail in “Sent from device” folder (I tried disabling it thinking Maildroid will be smart enough to save it in the IMAP’s sent folder, but no, it doesn’t).

Fairmail’s Settings->Send->Message->[Last Item] On Replying to a message in user folder, save the reply in the same folder was disabled (should be, or else it’d be messy), but there’s a subtext that says “The email server could still add the message to the sent message folder”, which points me to think saving a copy to the Sent folder is an IMAP server managed behavior, so it doesn’t rely on email clients specifically telling it where (which folder) to save the sent email.

I was about to give up Maildroid and stick to Fairmail, and did a little research on “imap put sent mail in sent folder” and viola, Maildroid is the first one that came up. Seems like I wasn’t the only one perplexed by Maildroid’s weird design choices and it seems like most other email apps do not have this awkward behavior.

I did as what the dev for maildroid said and it turns out all of the email accounts in use says “Not specified”. When I clicked on one of the accounts, the root folder /Inbox shows up. I had to expand it with the ‘>‘ so the (IMAP) sub-folders show up.

This GUI was designed horribly and it’s clearly an afterthought. The reason I’m saying that instead of just assigning the IMAP sent folder right away after I tapped on it, the UI changes the textbook at the bottom of the screen (WTF) to what I’ve selected (despite there were no multiple choices) and click the DONE next to it. It’s so unintuitive in many levels.

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Crack open wall wart (power brick): hot air method (READ or risk more damages!)

The power brick that came with my U1620A order has a rattling noise when I shook it. I suspected a piece of soldered cracked and was wandering inside so I chose not to power it on as it might short something. So I had to crack open the wall wart, which turns out many people have little luck open it up non-destructively.

Just prying it open by force with a screwdriver will ruin the plastics. I needed to somehow soften the glue first and work into it (like using a cutter) to dislodge/cut the glue. Rubbing alcohol doesn’t work that well. The glue is quite stuff so it’s not the easily dissolvable kind.

After some experimentation, I used my hot air station and set it to a temperature right below it melts the hard ABS plastic outside (143 deg C, max air flow), and carefully pried it after taking the heat away.

WARNING: Do not pry while the hot air is blowing as the ABS plastic might be slightly softened! The hot air might overshoot in its temperature feedback) so you might accidentally remold it. When working at the borderline temperature that barely soften the ABS plastic, the second you take the hot air away the plastic cools back (hardens) enough for you to pry.

Out of practicality, I heat up one edge at a time, then focus on 1/3 of the area at a time get an entry point prying one hook open at a time. It takes a lot of patience.

After I got all the 4 sides pried open for some reason I couldn’t release the case and it felt something was stuck in the middle. Turns out the wall wart I have happened to have a center screw hidden from plain sight under the label. The label quality was so good that just pressing it around with a pair of tweezers won’t find the screw hole (because of the tension). I used hot air (at the same 143 deg C) to probe with tweezers to locate the screw hole. I cut a hole in the label for the screw hole because it’d be a pain to use hot air to get the label off in one without ruining it and be able to put it back like new.


Bonus discovery: molded plastics have some memory!

I dented the ABS plastic case during prying (before I thought of using hot air), but I discovered this magical temperature (143 deg C) actually heals the plastic when I blow it in a direction that undoes the dent! The small (like 2mm) dents magically smooth itself out and went back to rough where it was before I screwed it up (pun intended)!

Yes, for molded plastics, small dents caused by prying and bumping, heating it up to the temperature right before it softens will return it to its near original shape without external forces!

Of course, do not go past the softening temperature (143 deg C). If you heat it to a melting temperature, the plastic will lose its memory so you need to apply external force to beat it to the shape you wanted (which is a pain in the butt and it requires a lot of post-processing to get it to look like original).

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Agilent DSO6000 series was internally called 54670/54680?

Architecturally, the DSO6000A series shares common designs with 54830 series oscilloscope and 54640 series oscilloscopes. I noticed the Acq board numbers for my DSO6052A start with 54672 and the my M/DSO6104A starts with 54684. Looks like the 5467X means 500Mhz and 5468X means 1Ghz while the X is the number of analog channels.

This is ‘confirmed’ by a slip up in the documentation (user guide) which they forgot to update the model number in their vector graphics:

I think I’m getting a hang of Agilent’s oscilloscope’s hardware to do deep level board repairs as I have various model to compare. I used If you need yours repaired, please reach me at 949-682-8145.

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Python packages, modules and imports

Python’s import structure is freaking confusing. Learning by examples (i.e. imitating example code) does not help understanding the logic of it, and there are a lot of possible invalid combinations that are dead ends. You need to understand the concepts below to use it confidently!

Just like C++ quirks, very often there’s valid reasoning behind this confusing Python design choice and it’s not immediately obvious. Each language cater certain set of use cases at the expense of making other scenarios miserable. That’s why there’s best universal language for all projects. Know the trade-offs of the languages so you can pick the right tool for the job.

MATLAB’s one file per function/script design

MATLAB made the choice of having one file describe one exposed object/function/class/script so it maps directly into the mental model of file systems. This is good for both user’s sanity and have behavioral advantages for MATLAB’s interpreter

  1. Users can reason the same same way as they do with files, which is less mental gymnastics
  2. Users can keep track of what’s available to them simply by browsing the directory tree and filenames because file names are function names, which should be sensibly chosen.
  3. Just like users, MATLAB also leverage the file system for indexing available functions and defer loading the contents to the memory until it’s called at runtime, which means changes are reflected automatically.

Package/modules namespace models in MATLAB vs Python

MATLAB traditionally dumps all free functions (.m files) available in its search paths into the root workspace. Users are responsible for not picking colliding names. Classes, namespaces and packages are after-thoughts in MATLAB while the OOP dogma is the central theme of Python, so obviously such practices are frowned upon.

RANT: OOP is basically a worldview formed by adding artificial man-made constructs (meanings such as agents, hierarchy, relationships) to the idea of bundling code (programs) and data (variables) in isolated packages controlled (scoped) by namespaces (which is just the lexer in your compiler enforcing man-made rules). The idea of code and data being the same thing came from Von Neumann Architecture: your hard drive or RAM doesn’t care what the bits stands for; it’s up to your processor and OS to exercise self-restraint. People are often tempted to follow rules too rigidly or not to take them seriously when what really matters is understanding where the rules came from, why they are useful in certain contexts and where they do not apply.

Packages namespaces are pretty much the skeleton of classes so the structure and syntax is the same for both. From my memory, it was at around 2015 that MATLAB started actively encouraging users (and their own internal development) to move away from the flat root workspace model and use packages to tuck away function names that are not immediately relevant to their interests and summon them through import syntax as needed. This practice is mandatory (enforced) in Python!

However are a few subtle differences between the two in terms of the package/module systems:

  • MATLAB does not have from statement because import do not have the option to exposed the (nested tree of) package name to the workspace. It always output the leaf-node to the current workspace, the same way as from import syntax is used in Python.
  • MATLAB does not have an optional as statement for you to give an alternative name to the package you just imported. In my opinion, Python has to provide the as statement as an option to shorten package/module names because it was too aggressively tucking away commonly used packages (such as numpy) that forcing people to spell the informative names in full is going to be an outcry.
  • Unlike free functions (.m files), MATLAB classes are cached once the object is instantiated until clear classes or the like that gets rid of all instances in the workspace. Python’s module has the same behavior, which you need to unload with del (which is like MATLAB’s clear).
  • Python’s modules are not classes, though most of the time they behave like MATLAB’s static classes. Because the lack of instantiated instances, you can reload Python modules with importlib.reload(). On the other hand, since MATLAB packages merely manages when the .m files can get into the current scope (with import command), the file system still indexes the available function list. Changes in .m file functions reflects immediately on the next call in MATLAB, yet Python has to reload the module to update the function names index because the only way to look at what functions are available is revisiting the contents of an updated .py file!
  • MATLAB abstracts folder names (that starts with + symbol) as packages and functions as .m files while Python abstracts the .py file as a module (like MATLAB’s package) and the objects are the contents inside it. Therefore Python packages is analogous to the outer level of a double-packed (nested) MATLAB package. I’ll explain this in detail in the next sections.

Files AND directories are treated the same way in module hierarchy!

This comes with a few implications

  • if you name your project /myproj/myproj.py with a function def myproj(), which is a very usual thing most MATLAB users would do, your module is called myproj.myproj and if you just import myproj, you will call your function as myproj.myproj.myproj()!
  • you can confuse Python module loader if you have a subfolder named the same as a .py file at the same level. The subfolder will prevail and the .py file with the same name is shadowed!

The reason is that Python allows users to mix scripts, functions, classes in the same file and they classes or functions do not need to match the filenames in order for Python to find it, therefore the filename itself serves as the label for the collection (module) of functions, classes and other (script) objects inside! The directory is a collection of these files which itself is a collection, so it’s a two level nest because a directory containing a .py file is a collection of collection!

On the other hand, in MATLAB, it’s one .m file per (publicly exposed) function, classes or scripts, so the system registers and calls them by the filename, not really by how you named it inside. If you have a typo in your function name that doesn’t match your filename, your filename will prevail if there’s only one function there. Helper functions not matching the filename will not be exposed and it will have a static/file-local scope.

Packages in MATLAB are done in folders that starts with a + symbol. Packages by default are not exposed to global namespaces in your MATLAB’s paths. They work like Python’s module so you also get them into your current workspace with import. This means it’s not possible to define a module in a file like Python. Each filename exclusively represent one accessible function or classes in the package (no script variables though).

So in other words, there are no such thing called modules in MATLAB because the concept is called package. Python separated the two concepts because .py file allowing a mixture of scripts, classes and loose functions formed a logical unit with the same structure as packages itself, so they need another name called module to separate folder-based collection (logical unit) and file-based collections (logical unit).

This is very counterintuitive at the surface (because it defeats the point of directories) if you don’t know Python allowing user to mix scripts, functions and classes in a file meant the file itself is a module/collection of executable contents.

from (package/module) import (package/module or objectS) <as (namespace)>

This syntax is super confusing, especially before we understand that

  1. packages has to be folders (folder form of modules)
  2. modules can be .py files as well as packages
  3. packages/modules are technically objects

The hierarchy for the from import as syntax looks like this:

package_folder > file.py > (obj1, obj2, ... )

This has the following implications:

  • from strips the specified namespace so import dumps the node contents to root workspace
  • import without from exposes the entire hierarchy to the root workspace.
  • functions, classes and variables in the scripts are ALL OBJECTS.
  • if you do import mymodule, a function f in mymodule.py can only be accessed through mymodule.f(), if you want to just call f() at the workspace, do from mymodule import f

These properties also shapes the rules for where wildcards are used in the statement:

  • from cannot have wildcards because they are either a folder (package) or a file (module)
  • import is the only place that can have wildcards * because it is only possible to load multiple objects from one .py file.
  • import * cannot be used without from statement because you need to at some point load a .py file
  • it’s a dead end to do from package import * beacuse it’s trying to load the files to the root workspace which they are uncallalble.
  • it also does not make sense (nor possible) to follow import * with as statement because there is no mechanism to map multiple objects into one object name

So the bottom line is that your from import as statement has to somehow load a .py file in order to be valid. You can only choose between these two usage:

  • load the .py file with from statement and pick the objects at import, or
  • skip the from statement and import the .py file, not getting to choose the objects inside it.

as statement can only work if you have only one item specified in import, whether it’s the .py file or the objects inside it. Also, if you understand the rationales above, you’ll see that these two are equivalent:

from package_A import module_file_B as namespace_C
import package_A.module_file_B as namespace_C

because with as statement, whatever node you have selected is accessed through the output namespace you have specified, so whether you choose to strip the path name structure in the extracted output (i.e. use from statement) is irrelevant since you are not using the package and module names in the root namespace anymore.

The behavior of from import as is very similar to the choices you have to make extracting a zip file with nested folder structures, except that you have to make a mental substitution that a .py file is analogous to a subfolder while the objects described in the .py file is analogous to files in the said subfolder. Aargh!

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Windows shortcuts to less easily accessible config pages

Control panel has a lot of kinda-secret calls that open specific configuration windows that it’d be difficult to get to (need many clicks from other windows) and they might not necessarily have a path that you can access normally when Microsoft discourage their uses. Sometimes it’s just a phrase, sometimes it’s a .cpl in Windows’ system folder, yet sometimes you can call a .cpl that does not exist at all yet the control panel recognizes it.

Here are some examples

control userpasswords2 opens a dialog box to manger user accounts more directly without going through MMC’s user management (typically Local Users and Groups within compmgmt.msc Computer Management). It’s also netplwiz

It used to be valuable way of managing autologon until Microsoft Removed the checkbox “Users must enter a username and passwords to use this computer” because it doesn’t make sense with their freaking vision of Windows Hello where you logon with biometrics or other ways that you’d do with your cellphones. They are trying to make passwords a thing of the past.

Autologin in windows 10 without password!
Credit: Auto login in Windows 10 without password? (softwareok.com)

control sticpl.cpl opens up Scanner and Cameras

I picked this shortcut up from the README file of Network TWAIN Driver installer, which plug and play doesn’t make sense because the device is on the network so there’s no hardware to detect. Instead you add a scanner device manually and enter the connection information in its properties.

The interesting thing about this one is that sticpl.cpl do not exist! There’s no control panel file (.cpl) anywhere in the system drive!


There are more information from Microsoft about these commands.

Lifewire has a better formatted table with additional alternative commands

With Powershell, you can get the canonical names of major control panel items and use it with control /name switch

This blog page has a cheatsheet for Windows direct commands, presented in the way Linux people rolls

You can even unhide some .cpl files through registry!

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Windows 10 Python Smart Aleck

Windows 10 comes with a default alias that if you type python anywhere in terminal, powershell, run, etc, It will run a stub that points you to getting it in Windows Store. WTF man! I hate these stubs that are nothing but advertising! People will know there’s Python available in the store if Python Software Foundation’s website announces it. There’s no need to hijack the namespace with a useless stub!

After I install Spyder 5.3.0, it started with a Windows console instead of a Python Interpreter console, so when I typed Python (Spyder 5.3.0 came with Python 3.8.10 in its subfolder), this damn App store stub came up:

When I tried to force a .exe exceution in Powershell, I saw this:

So there’s a way to disable this bugger off!

It’s not the first time Spyder not working as intended out of the box, but Microsoft’s overzealous promotion of their ‘good ideas’ causes grief and agony to people who simply want things done.

It’s

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