2022. december 31., szombat

End of 2022

This is some valuation of the year from this blogs perspective.

At the beginning of the year I was planning to write at least one post weekly. This would be 52 posts. Actually done 31.

Although, I'm not satisfied with the result, I is better than the previous years. The last year I was writing more, was 2018. I intend to achieve this as a goal for 2023.

Some highlights of 2022, also from my hobby perspective:

  • My new lab is still not finished, but I can tell, I moved in. Now I feel comfortable and spend more and more time in it
  • Finished the Videoton Melodyn project. I'm very proud of it. It was ready in time and functioning flawlessly
  • I closed my Hungarian language blog, what was running in parallel with this one. The decision come from anger at the first place, but today I feel, not writing (or translating) in to languages spare some time to me. So I keep it that way.
  • Started a few projects, what looks like shelved to me, also have a few revisited, but put back to the shelve:
    • E1300A Front connectors
    • Measurement control
    • CNC Router
    • Pan & Tilt gimbal
    • TL866II EPROM programmer update
    • PM3082 repair
    • Rackmount power amplifier
    • Function generator power amplifier
    • Contract project involving 4-20mA current loop and infra gates (not to discuss here deeper)
    • VFD display driver (even the first post of it kept in draft)

In 2023, I plan to work on my projects on a more organized way. Not to do many projects in parallel, focus on one, and finish it.

Also in 2020, I started to work on "project of the month", to force myself, to finish things in timely manner. This was washed by the COVID right at the beginning. I want to bring this back to life, to trigger myself.

Here I announce my January project (I really like to continue with more in February and further):

Fully working 3D printing

I've three 3D printers now. Actually only one of it working, and that one even kept in my old lab. Namely Anet A8, Geeetech i3 Pro, Anycubic Photon Mono 4k.
The goal, to have those fully working by end of January.

Those were my random thoughts for the end of 2022. I say good bye to 2022 with my current lab photos, and whish a


2022. december 29., csütörtök

New Arrival 8.

I mainly forgot to continue the new arrival series. Actually I just picked up some things today.
First a Philips PM6668 1GHz frequency counter for an insane €25.

As I have two counters already on the side of the ones I designed, I didn't keep it as I bought it for a friend who were looking for an RF counter for a while.
Also picked up three Leaver (Panasonic) VP-8193D generators for €125 each (to be honest, I payed for those at least a month ago already, just didn't find the time to pick it up)
One of it has a service sticker stating, it is dead, the others are untested, so those can also have problems. Some repair job is waiting for me on those.

On the side of the generator also picked up an ultrasonic cleaner for €75. It was a bit dirty, already cleaned it. It is bigger unit than my previous one. Also has a tap to drain the water, has heater and timer.
As a surprise the size is the same, what used by the ultrasonic record cleaners, what I intend to have. Now I don't need anything else than build the rotating mechanism for this. So, I have a new project. 😂

2022. december 28., szerda

"Melodyn" on Windows

As I successfully finished the Videoton Melodyn project, took into my head that I'll develop the software in it further.
Other than the radio itself, I have some shelved/planned projects what can good use of this software, I also need something to listen on my PC while I'm working.
In the last five years I worked exclusively for Linux projects professionally, but I still unable use Linux as development platform. The Linux desktop is not comfortable to me, so I'm using Windows.
The problem is coming from here.
I want to setup a development platform on Windows.
The mpd "on paper" is supported on Windows. Unfortunately the documentation, how to set it up is not existent.
So I downloaded, and was able to start mpd, on a trial-fail bases.
Download the latest mpd.exe from here: https://www.musicpd.org/download/win32/
Put it in the c:\mpd directory.
First it looking for a config file. I've no idea, what is the default location of the config file, so I put it next to the executable

audio_output {
  type "winmm"
  name "Speakers"
  device "Speakers (Realtek(R) Audio)"

This works with the Windows speaker on my PC.
In addition to this the mpd give the following error:

decoder: Decoder plugin 'wildmidi' is unavailable: configuration file does not exist: /etc/timidity/timidity.cfg

So I downloaded the wildmidi library from here: https://github.com/Mindwerks/wildmidi/releases
Put it under the c:\mpd\winmidi folder. Added to the mpd.conf the following also:

decoder {
    plugin "wildmidi"
    config_file "wildmidi/wildmidi.cfg"

With this, if I start the mpd with the following command line:

mpd.exe c:\mpd\mpd.conf

It start without error. The web radio from Melodyn.py works with it.
As I want to play audio files with it in the future, I don't know yet, if it will need additional setup.

Unboxing day

Finally after Christmas I arrived to my lab.

Look what arrived

First a whole set of Anycubic Photon Mono 4k printer:

To be honest I've no idea yet, how to make this thing working. Lot of reading, YouTube videos are waiting for me before I have the courage to start to print on it. Actually a 5l isopropyl alcohol I ordered for washing is not here yet. Also I may need some additional things to buy for keeping the whole thing clean.

I need to figure out soon, how to use this, as this little guy is eagerly waiting to be printed out:

Actually a few years ago I bought a Parkside column drill at Lidl. I'm not really happy with it from various reasons. Now here is the replacement:

I thank for my family those things. I'll get good use of it.

2022. december 25., vasárnap

Project - Videoton R4900 Melodyn 2.

Originally I was planning to write the series of articles about the build, what eventually didn't happen. I'm writing it now (on 25th December), for sure, many things will be missing.
This will be more series of pictures than a build log.

This is how it looked like at arrival:

I didn't even touch the radio until July. Just ordered a few parts:

This never be a "Hi-Fi" equipment, so a $1.75 class-D power amplifier and four wide range speakers are good enough. According to my plans, I also added two SMPS power supplies a 24V and a 5V one (later even I had in one of my parts boxes already)


I throwed away everything I didn't need, to have place for the new things installed. My intention to keep only the things inside, what doesn't change the look and feel.

Removed the complete power supply section, the power amplifier and all of the tubes.

Also removed the front cover with the original textile and the loudspeakers.

Power amplifier/loudspeaker section

The textile was cracked and the whole wooden plate wasn't fit to my new speakers, so recreated from starch. Added two wooden plate instead of the original one. One for the front holdinging the textile, one for the back for the speakers.

Drilled the holes for the speakers.

The amplifier/speaker section assembled.

Glue the textile to the new wooden plate

Put back the original (plastic) frame


Additional small things

I wanted to keep a few things from the original. The power switch, the volume knob, the backlight.
I guessed the backlight will be hard to find. Originally an E10 6.3V lamp was used (connected to the tube heater winding of the power transformer).
I was absolutely sure, I'll never find an E10 24V LED lamp:
AliExpress: - Hold my beer!

Changed the volume potentiometer to a new stereo one. Didn't find the one with the same length and finishing shaft. Bought some plastic extensions from the AliExpress, needed some work on it. Finally I was able to apply it correctly (no photos, sorry)
The power switch give me some headache. The original one was just partially working. Disassembled, but unable to fix it. So I crafted something into its place, what is not nice, but working (didn't have access to my 3D printer at that time, to create something better):


The controller should consist a Raspberry Pi (actually I had a few 3B, so used one), and a touch screen. Looked around, and from the reviews I choose a WaveShare 5" IPS, DSI, capacitive touch display (https://www.waveshare.com/product/raspberry-pi/displays/lcd-oled/5inch-dsi-lcd-b.htm).

It come out, just perfect. Worth every cent payed for it. Connected to the RPi with already installed RaspiOS, it just started to work. No software tweaking, no alignment, nothing.
From software perspective, I started from this project: https://learn.adafruit.com/raspberry-pi-radio-player-with-touchscreen
It gave some background on the mpd/mpc, but I didn't like the frontend (so rewrote it).
Other than installing the mpd and mpc, I only needed to setup the /etc/mpd.conf, with this configuration:

audio_output {
        type            "alsa"
        name            "My ALSA Device"
        device          "hw:0,0"

The others are handled by the Python code written. You also need this three Python packages: numpy, pygane, PyYAML

Controller mounting

Designed a mounting frame, what give the feeling of the original speaker grill, but can be opened to prevail the controller.

For the door lock I used the spring lock what can be used on many consumer electronics devices

The final assembly

The design, source code, etc. can be find here:

I'm thinking about, to create a "spin-off" project from the Python code and create a full blown network radio + media player from it. But this is question of the future...

Project - Videoton R4900 Melodyn 1.

This was written at 2022.04.14. Publishing it today as the surprise is over.
When I was a little child (before we bought out first Hi-Fi equipment in '81) we had a Videoton Melodyn radio. It is not particularly rare, or high quality. It just a radio from the bad side of the iron curtain.
Two days ago popped one of it on a Facebook group. It is sold on the local auction portal Vatera for an insane low price. (The picture is for illustration from www.radiomuseum.hu and not the actual unit)

I got some nostalgic feeling on it. I was thinking to buy it.
When I finally get the idea, what to do with it, it was already sold. 😔
Actually somebody had a comment under the original listing, that he has one and wasn't able to sell it for months now.
I contacted him, and today (2022.04.13) I picked it up. Payed $10 for it, and it was located in the neighboring district (not at a village at the other side of the city as the original listing's unit).
So the plans:
Actually my mother frequently listening some internet radio on the PC in the kitchen. It would be a great idea, to build an internet radio capable device for her into a familiar case (I just hope she remember to this radio and build some sentimental feelings on it). I plan to give her (and for my father) as Christmas present this year.
The plan in nutshell, how I see it now:
Add a Raspberry PI (I have currently a 3B unit in the drawer, don't intend to by a 4B in this chip shortage times for a fortune), buy a touchscreen LCD, a small but powerful D class amp, two new wide range loudspeakers.
Remove the original loudspeaker what mounted partially behind the left side plastic cover (next to the radio scale) and the upper textile cover. Mount the plastic cover to some kind of hinge, lock with "push to lock" plastic unit. Mount the LCD behind this newly created door. Mount the new loudspeakers exclusively behind the textile.
Find some internet radio linux distribution for the Raspberry, add PSU, the amp and that's it.
My mother eventually read my blog. Therefore this post was written for the drawer. I publish this (and the later parts) after Christmas.