Minisforum UM690 Main Board Removal

Last updated: Mar 27, 2024

This particular mini pc presents a puzzle when removing the main board. So, I am sharing my approach in hopes that it helps.

1 - Pry out the two rubbery feet and two triangular corner panels from the bottom; they are held in with some adhesive.

2 - Remove the four Philips-head screws just uncovered.

3 - Use a pick to gently pry off the bottom panel.

4 - Remove the four screws at the outside four corners of the main board. NOTE: DO NOT remove the four screws that are more toward the center of the board; two of which are underneath the memory cards. These hold in the processor heat sink and the metal thermal material to the other side of the board.

5 - Remove the SSD; don't lose the screw.

6 - Remove the Wi-Fi board that hides below the SSD; don't lose this screw either. The reason you are removing this is that the antenna lead is firmly attached to the case.

7 - The metal frame you can see around all four sides is firmly attached to the case. So, slip a pick between the metal frame and the front of the ethernet connector. Use this to gently pry the case side outward and the board upward. You may also need a second pick slid in between the metal frame and the far USB connector to keep it from catching on the metal frame. A little patience here and the board will be free of the case.

That's it. Mystery solved. Enjoy.

Software/Firmware Updates Ignorant/Annoying?

When a user installs a software update, why does the user have to answer any questions? The base/previous version is already installed and running. 

If the user has asked/agreed to an update and unless there are new options or other critical user interaction required, the software should just update itself silently.

Millions of person-hours are wasted with the user answering the same questions for every update -- over and over.

Samples of stupid questions:

Agreeing to the license (didn't the user already do that?)

Does the user really want the update - duh?

Click finish to complete the update (like there is another option).

NPN Transistor Saturation Mode Laboratory Measurement

The WWW has a lot of information, but finding actual circuit measurement of an NPN transistor saturation mode was, well, I never found any. Hence this experiment. I chose a common 2N2222A in a TO-92 package. On the DCA Pro 75, it measured:

hFE = 265 at Ic = 5.01mA

Vbe = 0.755V at Ib = 5.00mA

VceSat = 0.013V at Ic = 5.0mA and Ib = 1.00mA

 

The testing setup is in the following diagram:

 

A good description of a PN junction is give in this video: Forward biasing a PN junction.

A good description of an NPN transistor is given in this video: NPN Transistor Working.

Now for the actual measurements of our sample 2N2222A transistor:

Why do so many Windows applications misuse "appdata"?

Windows applications should not store static files common to all users (even if that is just one user) in the appdata folder. 

Common static files like:

• Executables (.exe, .dll, .jar, .bin, .js...)
• Collections (.cab, .zip, .7z...)
• Installation (.msi...)
• Configuration (.ini, json...)
• Data (ryo, .db...)

These should be stored in c:\ProgramData (there is a hint in the very name). 

Of course, you would ask why would anyone care? That is a good question. The answer is that when backups are made of the appdata folder, it is a waste of backup time and space to store these files; especially the executables which can be very large in aggregate if all the user wants is data that pertains just to them (after all, these files are in c:\Users\<userid>\...).

And if there are multiple users, then these files a mere duplicates wasting storage space.

My Early Impressions of the Lenovo Thinkpad T14

The major components, CPU, memory, ssd, display, keyboard, mainboard, power supply, cooling seem to function well and as expected. The cpu (and going with AMD was a major change) has performed well so far.

Now to the more annoying aspects:

• I use the track point buttons exclusively (trackpad clicking is turned off). the left button requires extra physical pressure to function correctly—even then not always does it work.
• The trackpad is not sensitive enough. Even with the sensitivity turned all the way up; it still just ignores some input.
• The trackpad also has the annoying attribute that the mouse will not move if it is accidentally touched with two fingers simultaneously—not a great design attribute.
• The wrist rest plastic and the bottom meet in the front corners in a less secure way (than the T470s). The left hand position causes the plastic to flex and creak (when will it break?).
• The wrist rest corners and edges are too sharp Especially the left, when using the track point left-click mouse button, is very uncomfortable.
• Using the USB C jack for power is not an industrial strength design. It is too small and too flimsy. If the A/C adapter USB C plug gets bumped, even slightly, I am sure it is going to damage the internal USB C jack. The previous rectangular “slim tip” was a much better and more reliable choice.
• I think that this keyboard is “noisier” than the T470s generation.

There you have it.

 

An Example of how Microsoft Views Software Stability and Robustness

This is right out of Microsoft's own official documentation. They are so busy off inventing the next latest change to the user interface that no one asked for that they can’t be bothered to stop and fix things that have been broken for years. There is a cultural problem at Microsoft that stems directly from it’s founder.

"Issues with the AutoComplete cache

This section describes known issues that can occur with the AutoComplete cache. The AutoComplete cache can become corrupted over time and may not save new entries. If this happens, you can try to remove individual entries from the list. To do this, see the How to remove AutoComplete list entries one at a time section. If that doesn't resolve the issue, the whole AutoComplete list can be reset. To do this, see the section titled "How to clear the whole AutoComplete list." "

 

GUI and Screen Size

It's past time for developers to learn two things: 

1 - Fixed size windows are POOR programming practice 

2 - Most users are NOT using 8K, 40+ inch screens 

What is a wonder is the arrogance of so-called software developers that they don't test their "beautiful" creations on a 12/13" laptop BEFORE they release it on an unsuspecting public. Windows that clearly don't fit and don't have scroll bars can be impossible to use. Fonts that are so large that the whole screen has very little data on it is extremely annoying. Layouts that are mostly "white space" are not very useful nor impressive. And this applies equally to pop-up windows as well as the main application window. 

GUI windows should automatically adapt to their physical display/monitor characteristics. They should, to a large extent, be dynamic in size. NO, they should not change to fonts so small that you need a magnifying glass to read them. And they should ALWAYS have vertical and horizontal scrollbars if they don't completely fit. 

You know that it just seems like common sense when building a GUI, but apparently such things aren't taught in "computer science" curriculums.