New Arrivals 7.

It's been a while since I wrote about, what is arrived, so this will be long.

Power AMP board

I bought a few 2x30W D Class amps. It cost $1.73 each. Actually I have a yet secret project, where I need it (just one, but bought 5, who knows, when it is needed)

Loudspeakers

Also for the project above. Four full range 3" Aiyima loudspeakers. I don't know if they are any good. I just hope, it will be good enough.

Akai AT-52

I've a project, I put a bit aside. Some of the people know me, knows that I'm a kind of collector for the old Akai Hi-Fi gears. The project is to repurpose the Akai AT-A1 tuner to a network audio player. I've a big setup of the "A" series equipment (VS-304, AV-U8, AM-A3, EA-A7, DT-A2, AT-A2, CD-A7, GX-R66, GX-R88, GX-R99, AP-A2). I feel it would be a great addition to this set.

Nowadays, I found an entry in the international Akai group on the Facebook. Somebody built a similar thing for the "Reference Master" series. "Accidentaly", I also have a Reference Master set. So I can't resist to order an AT-52 from the eBay for $8. The same unit he used for the project. Now I have it, I'll put on the list of future projects also.

Here is the link for the unit I seen. The video is somewhere in the comments. If you are not a member of the group,  you will not see it! Sorry.
https://www.facebook.com/groups/582950145140634/posts/4288775054558106/

Gimbal parts

I was writing previously about my gimbal project idea. The things I ordered for it, arrived.

The gimbal itself.

The remote control radio board.

And the unexpected. This little fellow was in the Electrodragon package arrived. I guess, by accident. I don't know, what this is good for, but I intend to figure out later.

VFD

Somebody was selling a bunch of nice VFD displays for just a few coins (around $0.5 each). So I bought ten of it.

Looked around a bit and find a suitable driver IC PT6324. Ordered from Aliexpress, it arrived also. Some design and build will follow in a separate post.

VXI function generator

I have several VXI mainframes already. Even function generator in it. But I couldn't resist. Bought an HP E1340A for $30. Brand new, in it's original box.

Nuvoton Dev kits

Postponed, but not forgotten project of mine to build a decent, new generation for my GPIB interface. Until now I built it based on ATMEGA328P + CH340G and an other version on ATMEGA32U4. Both using USB-CDC and the Prologix protocol.

During my later research I realized, I may utilize USBTMC for the interface. Yes, probably this still can be achieved with the 8bit AVR. But, would not be more fancy to use 32bit ARM for this?

The problem is that most (almost all) of the ARM MCUs built with 3.3V power and logic levels. The GPIB is still a 5V business. Yes, you can find ones tolerate 5V signals - but not generating it. If it come to the integrated USB requirement, the picture is even worst.

The only manufacturer I know, who added automated level shifters on every GPIO pins of the ARM MCU (only for Cortex-M0) is Nuvoton.

Previously, I played with Nuvoton MCUs with some success, until the CooCox IDE development and support completely dead. From that moment any free development platform seized to exists for Nuvoton MCUs.

A few years passed, and things happened:

• Nuvoton created his own Eclipse based free IDE
• Started to sell MCUs and dev kits directly on their web site.

The project above come into my mind, so I blow the dust from my old dev kits. Than I realized, the one I intended to use for this project is faulty. Unable to finish even the MCU initialization sequence.

This were the point, when I ordered new dev kits and MCUs for this project directly from Nuvoton.  They even provide 90% off from the first 5 MCUs from each type as sample. Those arrived also:

Pomona clips

Find some nice Pomona test clips locally for SO chips. These are never enough, so bought it.

Color headers

When I build something on a breadboard, it is always a struggle to connect to the external word. Specially for power connections (No I don't mean those nice breadboard capable power supplies. Those are only good for logic supply.). What if I build a small box with pin headers and banana sockets. If I do it this way, I need some color coding. So here a few colorful pin headers for this.

Magnifier

Have you ever had some equipment, what accidentally always fall into your hands when you need its functionality? Not because it is the best in its class, or whatever. Just because you feel it is best for you in that moment. For me, one of this things is a tiny folding magnifier. I have one for decades already. It was just a marketing gift.

As it serving me for long while, just pop into my mind: Why I don't try to find it online and buy a few to keep it around wherever I go. Found it on the AliExpress, so it is here now.

Door lock

This little fellow, you can find on many electronic equipment, mainly on the doors hiding additional buttons and knobs. I also needed it for my secret project mentioned above.

HP 3457A

I looking for it for a long time already. Usually find it on the eBay for high price, and from the other end of the world with horrible shipping cost.

I just realized this unit is selling from Hungary on the eBay. I had a hunch. I didn't know the seller profile but it felt like the guy I bought my VXI things and the Panasonic FM generator.

I wrote to him on the messenger. Is this yours?

The unit was in my hands two hours later.

From the desktop multimeters, never enough. 😆

Fluke (Philips) PM3082 Oscilloscope Repair 2.

The junk scope arrived. Yes it is a junk. At least mechanically. The front broken, few knobs also, the screen frame missing, the enclosure bent here and there.

Also it doesn't work. The low voltage power supplies looks OK, but nothing on the display, except the illumination. Even doesn't respond to the knobs, no startup beep.

Anyway. I wanted to quickly check my theory, that my original scope has probably a single failure on the processor board and no other problems.

So I gave a try. Swapped the processor boards.

Bingo.

The unit is working. At least it give sharp image, respond to the knobs/buttons. Didn't had time to check it further, but this is promising.

Here come the question:

Is it worth?

Worth to try to repair the other unit? Find missing knobs, print a new frame, glue the broken things, try to repair not just the processor board, but the other things could I face during the attempt.

I have some internal pressure to challenge myself, but ...

I don't know. We will see.

CNC Router Reborn 3.

I'm just able to move forward with this project just only small steps.

As I fitted the 600VA power supply for the spindle into a two unit high drive bay, I realized that it has a fan at the front. I didn't want to cover it with the regular PC plastic front panels to allow the air flowing.

So I designed a proper grill for the front, what match the PC front design.

Printed and assembled to the PSU:

I also worked on the spindle controller. It is ready made controller bought from the Aliexpress. It has controls and display, but needed some mounting hardware to fit into the PC enclosure. It is also 3D printed:

Assembled:

Wired together, the whole set. Measured the PSU. The LED display was a bit flashy from the first moment, finally completely stopped to work. As I not really have too much time to troubleshoot a such cheap, undocumented electronics (not worth the effort), so I ordered a few different kind of controller for a few bucks. This project put aside until those arrive.