A new member of the collection of old multimedia devices is the Panasonic AG-6400. The AG-6400 is a (semi) professional video recorder from the 80s. The device records on VHS magnetic tapes and also reproduces this standard. It is portable and was the recorder for the video cameras of that time. It draws its energy from 12V NP1 batteries and can provide approx. 27W for the camera connected to it. That was about the power requirement of a 3-tube camera.
This device, too, had gotten some traces of time that largely restricted its function. Simply said – it was broken. This defect manifested itself in a stuck capstan shaft . At first I thought the shaft was ‘seized’ due to corrosion, but the reason was completely different. Interestingly, a ball bearing had been pressed out of its press fit, so that the flywheel attached to the shaft touched the bobbin of the capstan motor. The magnets in the flywheel held it in place. This error could be easily and quickly remedied by pushing back the ball bearing and then fixing it.
the videorecorder without housuingpcb folded out to service positionview to the mechanics (drumhead)
After the mechanical fault was repaired and a first function test, a fault in the 5V power supply was still to be found on the power board. This was expressed by a failure to start all drives. Here, an IC fuse was defective in the switching converter. This was triggered by a defective Schottky diode in the buck converter circuit. This bug was also quickly solved. And after checking and adjusting the operating voltages according to the setpoints in the service manual, the drive did its job again. I was even amazed at the excellent image quality that the device could reproduce. Due to its compact dimensions, I can even use the AG6400 to digitize old VHS tapes in the future.
Elaborate wiring between the boards
frontview
In the data sheets and advertising for the AG-6400, the manufacturer has advertised some features and functions as follows:
High quality image reproduction
The tape speed corresponds to the VHS standard with a video track width of 49µm. Several technologies for clear and detailed image reproduction are combined in the device.
HI-FI Sound
A four-channel system consisting of two ‘normal’ audio channels with Dolby noise reduction and two ‘HD-Sound’ channels allow you to enjoy high quality recordings. A 3.5mm headphone jack and two 6.3mm microphone jacks for separate feeding of both channels, including separate control with VU meters, complete the range of audio options.
VU-meter and audio level controls
Time Code record and playback For control in linear editing systems, the recorder enables the recording of external EBU timecode signals on channel 2 of the longitudinal track.
External camersocket
A connection for an external camera with a maximum power consumption of up to 27W is also available. Cameras with 3-tube Vidicon system can be connected here.
A diagram with the connection options is shown in the following picture:
Occasionally I browse flea market websites for vintage and retro devices from the 70s, 80s and 90s. If an absolute bargain is in sight, then I strike and sacrifice a few euros. This time I found a whole box of Sony portable media players. The whole thing just cost me the equivalent of a pack of Cafe. However, the state of the devices in terms of function is also unknown. A particularly beautiful piece (yes – that’s always in the eye of the beholder) from this box is the Videowalkman GV-8E from Sony. This is a portable, analog video player / recorder that has a VHF / UHF television tuner and an LCD monitor integrated in one device. While that may not be anything exciting today, the GV8E was a very nice and expensive piece of technology when it was launched in 1988. So the portable lands on my table and gets its 6V DC supply from the power supply. The disillusionment comes as quickly as the initial euphoria. The device shows no function despite the power supply being upright. It does not react to any key press, no LED lights up. (Somehow I was expecting this or something similar)
But the ambition is too great not to look inside the device and to look for the problem. I quickly started disassembling and roughly dividing the device into its components. The service documents can be found online, which are very helpful here.
GV8E in parts
After examining the block diagram of the entire system, the start of the troubleshooting was the DC / DC converter board. This board, covered by a shield plate, produces all the voltages required for the supply of the individual components from the 6V input voltage. A measurement on the test pins on the board showed that some voltages were missing. So there must be a problem here.
solder side of the DC/DC converter boardpartside of the DC/DC converter boards
After removing the shield plate and inspecting the components, I noticed a defective 1.6A fuse (F103). This fuse protects the primary circuit of the switching converter. It can be seen from the plan that transistor Q114 was low-resistance and thus caused the fuse to trip.
extract from the circuit diagram of the DC / DC converter
The transistor is a 2SB1121 bipolar PNP transistor. Of course I didn’t have that in my collection. So thinned the component boxes for a suitable replacement …
replacement for the 2SB1121 is the PBSS5250Z
Then I found a PBSS5250Z, which has a slightly larger housing, but should do its job in the circuit.
defective Q114 desodered
Due to the larger design and the limited space available, I could only solder the replacement transistor upright.
Q114 renewed
Now a new fuse is still missing in the board. After installing and checking the other components in the affected circuits, the next function test was started. All boards electrically connected again and 6V connected to the battery terminals – and look – the Powersupply board starts up and the voltages are there. Now the GV8E can be switched on again with the power button, the LED also lights up and a quiet noise can be heard from the loudspeaker. However, none of the drive motors are running and the LCD monitor remains dark. The LED lights up briefly when the “Ejekt” button is pressed, but the motor responsible for ejecting the cassette compartment does not start. That means -> continue searching for errors. First of all I will take a look at the LCD monitor. It is quickly removed and dismantled. All the less pleasing is the condition of the board. Here the “decaying” electrolytic capacitors raged with their “body fluids”. (Of course this means the electrolytes)
Leaked electrolytic capacitors
The liquid electrolytes of the electrolytic capacitors have leaked over the years and have attacked the conductor tracks and also the solder joints. Sometimes it is so bad that small components, such as SMD transistors and resistors, fall off the board as soon as they are touched. At the latest now it is absolutely necessary to have the circuit diagram of the device at hand. Otherwise it will be difficult afterwards to correctly refill the missing parts. But first the old electrolytic capacitors had to be removed.
this is what the circuit board under the electrolytic capacitors looks like
With PCB cleaner I was able to remove the remains of the electrolytes and only then could I see the damage to the circuit board. Corroded areas had to be sanded with a glass brush and burned components had to be replaced. After cleaning again, the new capacitors (this time ceramic multilayer capacitors instead of the electrolytic capacitors) have found their place.
pcb with new parts
After this procedure the time had come. The next function test started. After reconnecting all plug connections and the power supply, there were further signs of life. The backlight (CCFL) started again and in the upper left corner it was “00:00” to see the flashing clock of the on-screen display … Unfortunately, that was all. The OSD display was very blurry and the rest of the picture was white. The brightness controls did not respond. So the board had to be examined “big”.
The board of the LCD monitor still had many broken conductor tracks, which had to be laboriously repaired with individual strands and enamelled copper wire. There were also some SMD components (resistors and transistors) so corroded at their connections that only an exchange helped. The result looks a bit wild, but another function test was finally positive.
fixed displayboard
After I reassembled the monitor, I went to the drive. Here, too, I first checked or renewed all SMD electrolytic capacitors, as ALL of them had really leaked out. Fortunately, the circuit boards here were not so severely etched and can be easily cleaned. Then the function test came. And unfortunately there were still problems here. There was no cassette ejection and no reaction from any of the drives. After studying the service manual and measuring many supply voltages, I was able to identify a processor as a source of errors. It is a SONY CXP80116.
Sony CXP80116
This chip controls all drives, leds, queries sensors, etc. It is also responsible for ejecting the cassette compartment. It controls a driver IC (bridge) via pins 20 and 21, which in turn supplies the charging motor. And exactly the two outputs remained at 0V. When the “Eject” button was pressed, only a few millivolts were measured instead of the 5V. So at first there was a suspicion that the driver IC has an error and is pulling down the outputs of the controller. So the outputs from the controller to the motor driver were separated and 5V directly connected to the motor driver input – and lo and behold, the loading motor was activated. So the problem is with the 80116. After some back and forth I was able to find one of these and exchanged it. Another test pleased me, because the cassette could be loaded again and the head drum started.
And the next problem already appeared. One of the two loading arms only drove half off and then got stuck. That means I also have to disassemble the mechanics of the drive. Said and done. Fortunately, it was only a small bolt that holds a drive lever. This had loosened and slipped out. So the problem was quickly resolved. Now I was finally able to do a function test again. And this time everything worked. The cassette was loaded, the head disk started, the tape was threaded and finally it could be played. After I had tested all functions, the GV-8E can be reassembled. Now he can go to the showcase as a “museum piece”;)
working again
Technical data of the GV-8E:
Video recording System: Rotierendes Zweikopf-Helical-Scan-FM System
Audio recording System: Rotierender Kopf, FM System
The bench multimeter from Keithley is an old companion in the field of measuring instruments. The types of the 2000 series are predominantly used in our laboratories. They are available in different equipment variants with regard to the interfaces to the outside world. Here GBIP bus is of course a standard, as is RS232. The newer devices now have a LAN interface with which communication via the Internet protocol is possible. Each of these interfaces can be used to communicate with the device using “Standard Commands for Programmable Instruments” (SCPI). In this example I will control the Keithley 2000 via Matlab and read out measured values cyclically over a longer period of time, save them in Matlab and finally output them in a plot – virtually configure a simple data logger. The purpose of this setup is to record the voltage curve (or current) of a rechargeable battery or battery of a low-energy device.
backside of the Keithley 2000GPIB Interface (IEEE488)RS232 interface
In this example I will use the serial data transmission via the classic RS232 interface, as this is completely sufficient for my application. In addition, I can save myself the installation of the driver packages for the GPIP-USB interface. 🙂 Since many of the current computers and laptops no longer have any RS232 ports, a USB-RS232 adapter (e.g. FTDI232 etc.) is required.
USB-RS232 Adaper am Keithley2000
Once the connection between the multimeter and the computer has been established, communication can take place via a Matlabscript, as in this example. The Keithley only needs to be told that it should “talk” over the serial interface. The following code snippets show how you can easily read out data via SCPI:
serialObject = instrfind('Type', 'serial', 'Port', 'COM26', 'Tag', '');
%serialPort = 'COM23';
%serialObject = serial(serialPort,'BaudRate',9600, 'DataBits',8);
if isempty(serialObject)
serialObject = serial('COM26','BaudRate',57600, 'DataBits',8);
else
fclose(serialObject);
serialObject = serialObject(1)
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Sourcemeter 2000 setup
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
fopen(serialObject)
% fprintf(serialObject,':*RST')
time = now;
voltage = 0;
%%
figureinstanz = figure('NumberTitle','off',...
'Name','Spannungslogg',...
'Color',[0 0 0],'Visible','off');
plotinstanz = plot(voltage,time,'Color','red');
%% Messzeit und evtl Messintervall
stoptime = 10; %60 seconds
timeInterval = 1; % brauch' ma jetzt nicht
% Messgeraet einstellen
fprintf(serialObject,':SOUR:FUNC:MODE CURR'); % current source selection.
fprintf(serialObject,':SOUR:CURR:MODE FIXED'); % changes voltage mode to fixed
fprintf(serialObject,':SOUR:CURR:LEV 0'); % sets current to 0
fprintf(serialObject,':SENS:FUNC "VOLT"');
fprintf(serialObject,':SENS:VOLT:PROT 4');
%fprintf(serialObject,':SENS:CURR:RANG:AUTO ON');
fprintf(serialObject,':SENS:VOLT:RANG 10');
fprintf(serialObject,':FORM:ELEM VOLT');
% %fprintf(serialObject,':TRAC:COUN 1');
% %fprintf(serialObject,':TRAC:FEED:CONT NEV');
%
%
% fprintf(serialObject,':TRAC:CLE');
%
% fprintf(serialObject,':TRAC:POIN 10');
% fprintf(serialObject,'TRAC:FEED:SENS');
% fprintf(serialObject,'TRAC:FEED:CONT NECT');
% fprintf(serialObject,'TRIG:COUN 10');
% fprintf(serialObject,':OUTP ON');
%
% fprintf(serialObject,':INIT');
% fprintf(serialObject,':TRACE:DATA?');
%% Daten abholen
count = 1; voltage(1)=4
tic;
time=toc;
% while time<=stoptime
while voltage>=1.5
% fprintf(serialObject,':INIT');
% fprintf(serialObject,':TRAC:FEED SENS');
% fprintf(serialObject,':TRAC:DATA?');
%
fprintf(serialObject,':READ?');
voltage(count) = fscanf(serialObject,'%f');
time(count) = toc;
set(plotinstanz,'YData',voltage,'XData',time);
set(figureinstanz,'Visible','on');
pause(timeInterval);
count = count +1;
end
figure(1);
plot(time,voltage);
grid on; hold on;
xlabel('Zeit [s]'); ylabel('Batteriespannung [V]')
title('Spannungsverlauf Batterie 3V Lithium (2032 mit Modul) im default mode');
% fprintf(serialObject,':OUTP OFF');
%% Put the instrument in local mode
fprintf(serialObject,'SYSTEM:LOCAL');
fclose(serialObject);
The following plot shows what such a data log looks like. Here, the voltage curve of a nearly discharged battery is recorded over time until the consumer is switched off.
In this post I would like to devote myself to something else. It’s not about retro technology, it’s about a little thing that makes working in the office/lab easier. One of the many measuring devices I deal with is an old Agilent LCR meter. As is known, the LCR Meter 4297A can be used to measure the inductance, capacitance, etc. of electrical components and generally of structures which are assigned to the electronics / electrical engineering sector. Roughly speaking, the 4297A actually only measures current / voltage, the phase relationship between the two and the energy direction. And at a certain frequency. All parameters such as L, C, R, X, Y, Q, PHI, … are then mathematically calculated and output from these parameters. The frequency here can be set from 1MHz to 3GHz (in 100kHz steps). Ideally, the measuring device can measure not only in one frequency point, but also in many. By “many” is meant here that the measuring device can generate frequency tables with 32 entries. There are eight of these tables. This makes it possible to display the course of a measured variable in the form of a curve. However, this is quite cumbersome. The contents of the tables must be exported and saved manually (as “csv” files) table by table. This means that each table must be selected individually. Then select the “Export List View” dialog – then specify a storage path and file name. Only now are the first 32 records exported. This process must be repeated eight times in total. It is saved on a 3.5 inch floppy disc – the only available medium. You could also hang the 4297A optiona on a LAN and set up file sharing. However, manual export is not spared. The .csv files can now be opened on a “normal” computer. They must then be put together manually in postprocessing. Only now can a diagram be made from the data. Here Matlab from Matworks is a good tool, which is often used in our laboratories as part of training.
NI GPIB – USB Controller
To simplify this cumbersome process considerably, I created a small script that communicates with the measuring device using the SCPI commands (Standard Commands for Programmable Instruments). That means: The measuring device is connected to a PC via a GPIB-USB controller. A Matworks Matlab installation including the required toolboxes is located on the PC. The Matlab script should now simply switch through the tables in sequence and read out the contents of the individual parameters and save them in an array. The content of the arrays is then displayed directly in a plot. However, this method only uses the contents of the tables. It would of course also be possible to set any desired frequency directly in a loop using the script, read out the measured values, select the next frequency, etc. This would max. Total 29990 points over the entire frequency range. The eight tables, each with 32 points, only allow 256 points. For now, however, that is sufficient and also much faster.
Transmission Line 50 Ohm termination resistorline is terminated
The example shows the impedance curve (Z curve) of a 50 Ohm transmission line. The end of the line is terminated with a 50 ohm resistor. The frequency range is 1MHz to 3 GHz. The situation is different if the line is open or closed briefly. The electromagnetic wave is then not converted into thermal energy at the end of the line, as in the “matched” system, but is reflected back into the system.
line is shortened
The following very simple Matlabscript enables the reading of the measuring device parameters. The script serves as an example of how to get the measurement data quickly. The programming manual of the manufacturer of the LCR meter lists all SCPI commandos and plenty of examples with which you can communicate with the measuring device.
%auslesen der agilent LCR Keule 4287A
%gekodet von ingmar bihlo Ende November 2017
%anschluss über gpib ni adapter
%LCR gpip adresse: 5
%%
%vorarbeiten an LCR Keule
%
% Es müssen 8 Tabellen mit je 32 Punkten definiert sein
% (power und average ist egal, wird nicht ausgelesen)
% die CALibration muss gemacht worden sein
% unter "measurement parameters" muessen vier parameter definiert sein
% zb. Z, qhi, R, L, etc... diese sind dann in den variablen param1 bis 4
% enthalten
%%
% gpib interface oeffnen und identifier lesen
g = gpib('ni', 0, 5);
g.InputBufferSize = 100000; % Set the buffer size
fopen(g);
fprintf(g, '*IDN?')
idn = fscanf(g);
fclose(g);
num1all=0; % initialisieren der variablen für den summenvector
num2all=0;
num3all=0;
num4all=0;
freq=0;
fopen(g);
%read list parameters (frequency points)
fprintf(g, ':SOUR:LIST?');
fpoint=fscanf(g);
listchar=strsplit(fpoint,',');
list=[cellfun(@str2num, listchar(:,1:end))]
clear listchat; clear fpoint;
%analyze list content
points=freq(1);
for i=1:8
%Tables selecten
fprintf(g, strcat(':SOUR:LIST:TABL 0',num2str(i)));
pause(1); %pause 1s zum umschalten der tabelle
%parameter1 abholen
fprintf(g, ':DATA:FDAT1?'); %parameter 1 anfragen
par1=fscanf(g); %parameter 1 holen
string1=strsplit(par1,','); %parameter 1 string nach komma zerlegen
%num1=[cellfun(@str2num, string1(:,1:end))] %parameter 1 strings in dec konvertieren
num1=[cellfun(@str2num, string1(:,1:end))];
num1all=[num1all,num1]; %parameter1 aktuell mit parameter1 aus vorherigem durchlauf concentenaten
fprintf(g, ':DATA:FDAT2?');
par2=fscanf(g);
string2=strsplit(par2,',');
num2=[cellfun(@str2num, string2(:,1:end))]
num2all=[num2all,num2];
fprintf(g, ':DATA:FDAT3?');
par3=fscanf(g);
string3=strsplit(par3,',');
num3=[cellfun(@str2num, string3(:,1:end))]
num3all=[num3all,num3];
fprintf(g, ':DATA:FDAT4?');
par4=fscanf(g);
string4=strsplit(par4,',');
num4=[cellfun(@str2num, string4(:,1:end))]
num4all=[num4all,num4];
%read list parameters (frequency points)
fprintf(g, ':SOUR:LIST?');
fpoint=fscanf(g);
listchar=strsplit(fpoint,',');
listraw=[cellfun(@str2num, listchar(:,1:end))];
list=listraw(:,2:end); %von pos2 das feld schreiben (an pos ist die anzahl der zeilen)
for c=1:3:96
freq=[freq,list(c)]; %von jedem 3. wert aus list ein neues array bilden
end
clear listchat; clear fpoint;
pause (1);
end
%%
%ausgabevariablen festlegen
frequency=freq(:,2:end);
param1=num1all(:,2:end);
param2=num2all(:,2:end);
param3=num3all(:,2:end);
param4=num4all(:,2:end);
%%
% Cell array richtig uma drahn
x1=param1(1:32);
y1=param1(33:256);
param1 = [y1 x1];
x2=param2(1:32);
y2=param2(33:256);
param2 = [y2 x2];
x3=param3(1:32);
y3=param3(33:256);
param3 = [y3 x3];
x4=param4(1:32);
y4=param4(33:256);
param4 = [y4 x4];
%%
%uerberflüssige variablen loeschen
clear c; clear i; clear list; %clear freq;
clear par1;clear par2;clear par3;clear par4;
clear string1;clear string2;clear string3;clear string4;
clear num1all;clear num2all;clear num3all;clear num4all;
fclose(g);
%plotten der ergebnisse
figure(1);
plot(frequency,param1);
grid on; hold on;
xlabel('Frequency [Hz]'); ylabel('Measurement Parameter1 |Z| [Ohm]');
title('Agilent LCR Keule');
figure(2);
plot(frequency,param2);
grid on; hold on;
xlabel('Frequency'); ylabel('Measurement Parameter2');
title('Agilent LCR Keule');
figure(3);
plot(frequency,param3);
grid on; hold on;
xlabel('Frequency'); ylabel('Measurement Parameter3');
title('Agilent LCR Keule');
figure(4);
plot(frequency,param4);
grid on; hold on;
xlabel('Frequency'); ylabel('Measurement Parameter4');
title('Agilent LCR Keule');
The Sony TC-150 is the newest, old member of the collection. Once again purchased as a defect device, this baby found a place in the workshop. After a quick inspection, it was immediately clear that the ravages of time were gnawing and, as is often the case, the drive belts became brittle or decomposed. Otherwise, the device is in perfect condition, hardly any scratches and damage to the case. The battery compartment was also clean. There are four belts of different lengths in the device.
belts to replace
Suitable replacement belts can be obtained, for example, from a large electronics store that is represented in Austria by six megastores. You will quickly find what you are looking for under the name “drive belt range” and “1.1mm edge length”. Replacing the straps is less quick. Here you should take at least half an hour and carefully take the drive apart.
The main circuit board must be removed in order to access the pulleys or to be able to unscrew them further. However, this is only possible if some lines are unsoldered. Only then you can fold up the board. Once that’s done, you can unscrew the retaining plates above the pulleys. They form the backing of the flywheels (capstan shaft). On this occasion, it is advisable to check the capstan shaft for dirt (due to belt wear) and damage, or it should be cleaned. The pressure roller must not be neglected either. In this model, both were in great condition. The pinch roller was neither glazed and brittle, nor contaminated with tape wear or shrinked. So I could put on the new straps. The main belt from the engine is put on with a rotation of 90 °. Here you should note the installation position of the old belt, if it still exists, or at least do a short test run after fitting the new belt.
If everything turns again (and especially in the right direction) then the assembly can be done. Solder the wires again, screw the circuit board and the repair is done. To have this man a test cassette, here are some parameters, such as tape speed or the tracking of the tape head, which are given and adjusted if necessary.
the TC150 after belt replacementthe VU-meter for recording level control to as battery meter
Technical data of the SONY TC-150:
Vendor: Sony
Type: TC-150 (Europa) bzw. BT-50 USA
year of production: ca. 1977 – 1982 (according to various sources)
Modell kind: portable Cassette Corder
Hauptprinzip: NF-Audio
Magnetbandaufzeichung/Wiedergabe
tape speed: 4.8cm/s
heads: 1 recording-/playback head
1 earase head (Permanentmagnet)
semiconductors: 8 tranistors, 5 diodes, 2IC´s, 1 FET
Power : Outputpower: max 360mW
Powerconsumption : max 9W
Supplyvoltage: battery 4×1.5V AA, or accupack BP28
12V Caradapter bzw. 6V 4W wallplug
operationtime: 2.5h at continous recording
Speaker: dynamic 5cm Lautsprecher
Abmessungen: 174 x 29.5 x 113 mm (BxHxT)
weight: ca. 769g
This beautiful, small, new piece of technology from the eighties has been added to my collection. It is a small tube radio receiver with radio part called CIRT-2097T from the manufacturer Broksonic (according to Internet research it is an US company). The device I received with the attribute “defective” quite cheap on a flea market platform. So I thought, the risk can be taken and risk a repair attempt. What great things can not be broken – if it’s not just the picture tube.
inside the Broksonic
After a short functional test with the plug-in power supply, it soon became clear that nothing was working. No picture – no sound, no nothing. Since the device also has a battery compartment, I next wanted to try to feed the power via the battery terminals to see if there may already be a problem. And there it was already – the problem. The battery cover was almost impossible to get off, it held as glued. After some back and forth, I got the lid but then non-destructive and it revealed the cause of “jamming” or better “gluing”. There were still batteries in the battery compartment (probably for 20 or more years). They were in a bad condition, totally corroded and leaked. In part, the outer coat of the cell was corroded and no longer available. Oh dear – I thought, hopefully the leaked dielectric did not move inside the unit and did damage there. There was nothing left for me to do but to disassemble and check everything. And then the evil manifested itself:
from leaked battery cells distroyed pcb
About a quarter of the TV board had come in contact with the battery fluid. And the stuff has done a great job, etched away almost all the traces and leads from components.
So I first tried with PCB cleaner to remove all the crystals and the rest of the battery juice to get a closer look at the damage. A few random measurements with the ohmmeter quickly showed that many traces were severed. So it did not help, the tracks had to be uncovered. Only then would a reasonable repair possible.
Rough cleaning with the brass wire brush
With a rotating brass wire brush, I then began to remove the etched areas, remove the remains of the solder resist and expose the copper traces.
Fine work with glass brush
After the rough preliminary work had the glass brush ran. Only with that it was possible to remove all paint and corrosion residues and finally expose the traces. A tedious job …
the exposed and repaired copper tracks
… but finally it was possible to uncover and repair all damaged areas. Some resistors and capacitors also had to be renewed because their leads were also in poor condition.
After the repair, a bump test could then be carried out – lo and behold, there was no further error and the device was working properly again. So I was able to protect the repaired area of the board with solder varnish from renewed corrosion and reassemble the device.
Finally, here is an overview of the technical data:
vendor: Broksonic (US-Firma New York)
type: CIRT-2097T
year of production: ca. 1982
model: TV+FM Empfänger portable
receiverprinciple: Superhet
screensize: 2 Zoll SW Bildröhre
bands: AM, FM, SW (Radio), VHFI,VHFIII,UHF (TV)
AM: 535-1605kHz
SW:3200-9700kHz
FM:88-108MHzTV:
VHF Kanal 2-13(US), 2-12 (E)
UHF Kanal 14-83(US),21-69(E)
supply: battery or accu, AC with adaper
supplyvoltage: accu 6V, battery 6×1.5V AA
speaker: dynamic 16 Ohms speaker
outputpower: 150mW
dimensions: 150x53x202 mm (BxHxT)
weight: ca 1.1kg
The Nintendo company launched the Nintendo Classic Mini game console and put it on sale in 2016. It is a revival of the original 8-bit game console Nintendo Entertainment System from 1983 (release in Japan) and 1986 (release in Europe). The original NES console has sold around 61 million times and was replaced in 1992 by the SNES (Super Nintendo Entertainment System) a 16-bit console. The popularity of the Nintendo consoles is apparently so great that the new edition was sold out shortly after its release with a retail price of around 60 euros. Here traders sensed the big deal and offered the devices on Amazon, ebay and the like at sometimes horrendous prices. Even now, almost a year later, they are still not available for less than 100 euros. And Nintendo doesn’t produce any other units either. Instead, the same game began with the revival of the SNES series in miniature.
The NESPI in its packaging
But there are other ways you can get a miniaturized version of this console for a lot less money. For a few euros you get a case called NESPI CASE, which corresponds to the NES CLASSIC MINI, but with one big difference: you can install the computer yourself in the form of a Raspberry PI. This opens up countless possibilities to use emulator software to recreate your own consoles using software. The NESPI case has an integrated 4 port USB hub and a LAN Ethernet connector that leads the connections of the Raspberry PI to the outside. Two USB ports are arranged in such a way that they serve as controller connections. The other two USB ports and the Ethernet connection are located under the device flap, where the game modules were once inserted. The device is equipped with a power switch with a power LED and a reset button.
NESPI Case unpackedControls and connections
The housing is supplied with pre-assembled adapter boards. The screws for mounting the Raspberry Pi and the housing shells are also included in the scope of delivery. A small included Phillips screwdriver and a piece of paper with assembly instructions make things even easier.
Raspberry PI in NESPI-Case
The LAN and USB ports of the RaspberryPi are routed to the outside via the cables and plugs on the adapter boards. Once the plug connections have been made, the RapsberryPI board can be screwed into the housing. Optionally, a 5VDC fan with the dimensions 30x30x10mm can also be attached to the housing cover using locking lugs. A two-pole pin header is available on the circuit board for the power supply of the fan. Once everything has been installed and connected, the upper part of the housing can be screwed on.
Raspberry Pi eingebaut
The software can now be set up. I prefer the images from retropie or recalbox. More information can be found on the relevant websites. Once the desired emulators have been set up, you only have to transfer the game files, the so-called “Roms”, that is, binary copies of the game modules of the original hardware in a .bin or .rom or .iso file etc. to the SD card or USB Copy the stick and integrate it into the “EmulationStation”. And you’re ready to go. The USB controllers in the NES look are also available for just a few euros from China …
NESPIE with NES-Nachbau “ChinaController” attached
I received a new kit for vacuum fluorescence display from Günter (gr-pojects). Thanks a lot!
It is a clock with Type IV-11 vacuum fluorescent display tubes for hours, minutes and seconds, and an IV-18 tube for date display, and IV-3 for displaying the day of the week. The clock consists of a mainboard with power supply, CPU, MP3 module and driver blocks for the tubes. The time is set and synchronized via an externally connected DCF-77 receiver. Later, the board will be extended with a real-time clock circuit. The power supply for the entire circuit comes from a small plug-in power supply with 12V / 1.2A. The total power consumption is about 450mA. As a special feature, the clock has a small MP3 sound module with MicroSD card slot. This receives from the microcontroller via the serial interface every quarter of an hour a corresponding command to play an MP3 file. Thus the quarter of an hour is signaled with a “gong beat”, half an hour with two and three quarters of an hour with three “gong strikes”. At the full hour, the corresponding time is announced.
The entire circuit is built into an aluminum-acrylic housing. All fittings are milled and screwed. A video of the structure and the function can be seen below:
In the years 1968 to 1970, the radio receiver was built with the inscription “Philetta Euro 280” by Philips. It is a small multi-band receiver with transistor equipment. The type designation 12RB280 / 30 with the inscription “Sonata” seems to be another version of this model. In any case, I have dug up the version “Sonata” – once again from the depths of the Kellergefilde – and after superficial cleaning connected to the mains. Immediately after switching on, the scale illumination lights up and a loud 50 Hz hum can be heard from the loudspeaker. Increasing the volume level adds some noise. So switched to the FM band and searched for a station – and lo and behold, it works. Only the buzzing disturbs. Otherwise, the device works without any major problems. To find the cause of the humming, you begin with the troubleshooting as usual in the power supply.
entfernte Rückwand
The rear panel is quickly removed and the power supply unit, consisting of a, mounted on a support plate transformer including rectifier and filter capacitors removed. Now, without using the oscilloscope and the multimeter, you can immediately see where the ravages of time have left their mark. The two electrolytic capacitors do not look quite healthy anymore.
A quick measurement of the voltages brings certainty. The DC voltages have a decent ripple, which causes the “hum”. So the function of the electrolytic capacitors to smooth the DC voltage is no longer, or poorly, given. A measurement of the capacities confirmed that. So I renewed the capacitors.
Power supply with renewed capacitors
Immediately after switching on, even before I had the probe at the measuring points, a noise was heard without “humming”. The oscilloscope image now showed a clean DC voltage – almost no ripple. The receiver worked again very clean, without disturbing background noise. That was apparently the only mistake.
Technical information:
The main principle of the receiver is a superhet (according to the superposition principle) with an IF of 460/10700 kHz. The waveband of the receiver:
frequency scale
long wave
medium wave 1 (520-1400kHz)
medium wave 2 (1400-1600kHz)
shortwave
UKW
The output stage has a power of 3W, which is converted into sound energy in a dynamic loudspeaker with permanent magnetic excitation. The case is made of plastic and has the dimensions 43×17.5×10.5cm with a weight of 2.4kg. The receiver is supplied with 220V / 50Hz mains voltage.
From the early 1980s comes the “City Bummler” a mobile, portable cassette player – in short a Walkman. At that time, I received it as a Christmas present during my middle school years. The special feature of this device was a built-in microphone and two headphone ports. So you could listen to music in pairs and if you wanted to say something without having to remove the headphones (or to reduce the volume), so you had to press only an orange colored button and the intercom was active. The device was sold as a low-priced “replica” version of the first Walkman from Sony, the TPS-L2 which came on July 1, 1979 on the market. The citybummler was distributed by UNIVERSUM via the source mailer.
City Bummler with a self made coverplate after the original got broken
The device was delivered in a box with headphones, cassette pocket and carrying case with strap. For operation, three AA size 1.5V batteries were needed. The volume control is carried out with two separate sliders, so that each channel can be controlled separately. Unfortunately, the city loafer has not passed the last 35 years quite unscathed. Over time, the cassette cover was broken off, which I then replaced in my youth with a homemade tinplate lid. At some point I did not like the case color and I painted the device green. (or I just had green paint at hand). At least the “loafer” still exists and it works too.
I was then on the Web in search of a well-preserved, in the original state city loafer. However, the offer is extremely low and the few offers on online auction houses are not interesting because of the immense shipping costs.
Fellow FE-1
But a compromise and at the same time a new piece in the collection is the FELLOW FE-1 Walkman. I got the most cheap and fully functional on a second-hand stock market.
left: Fellow FE-1, right: City-Bummlerboth devices in comparison
The Fellow is also a clone of the Sony TPS-L2. It differs essentially in the arrangement of the keys of the drive.
