To all electronic enthusiasts!

I kindly ask you all, that you carefully consider and think about all the websites you have used to learn about electronics, all the forums you have trawled through for information and the vast amount of videos on youtube that has helped you understand and solve a problem.

This information only exists because there are people wanting to let the information live on, from user to user, open platforms like personal websites and forums are indexed and made searchable by almost any search engine on the internet. Imagine if all you ever found on google was closed facebook profiles and no information.

This is a circle of information sharing that has been broken, the eco system of knowledge sharing is dying with social media.

Only uploading pictures of your experiment with a short sentence or “science!” is destroying the electronics hobby, if you value what you have learned on the internet, then give it back to the internet, make your own website or, less time consuming, write a good long thread on a forum about the technical issues you had and how it was solved.

Do not worry about if you think that your english is not good enough, do not fear that you make yourself look inexperienced, so would I in many fields of science and there is no way that I master every aspect of electronics. Ask, Learn and Help each other!

There is a generation gap right now, 20 years ago everyone shared their knowledge on mailing lists or had a html website, next leap came with the blogs where focus could be moved to creating content and not maintaining code, but with social media, all control, history and indexing is gone. There is no information left for the future generations, because it is all posted on closed social media groups. Content is mixed, unorganized and for the most lost for the user after a couple of weeks, way down the stream.

Fight the loss of knowledge! Make a website or post on a forum! Only use social media to link to your website/forum post. This is the only way for the information to live on.

I hope you will share this call to arms with like minded electronics interested people.

Kind regards
Mads Barnkob
Administrator of
Author of
Moderator of
User of forum and forum

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Nokia Siemens Networks Flexi WCDMA teardown: integrated Doherty amplifier (part 5)

Nokia Siemens Networks Flexi Multiradio BTS is a GSM/EDGE, WCDMA/(I-)HSPA, and LTE base station for use in mobile telecommunication antenna networks. A network that you use daily on your cellphone. Teardown of a NXP BLD6G22L-150 integrated Doherty amplifier from a Nokia Siemens Networks Flexi WCDMA base station.

The previous teardowns that are also highly related to this Part 1: System station, Part 2: Power Amplifier and Part 3: Antenna

All high resolution pictures of the PCB, ICs and Doherty amplifier for this video can be found in part 4: another Power amplifier

The following 9 minute video shows the teardown step by step with explanations.

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Nokia Siemens Networks Flexi WCDMA teardown: Power amplifier (part 4)

Nokia Siemens Networks Flexi Multiradio BTS is a GSM/EDGE, WCDMA/(I-)HSPA, and LTE base station for use in mobile telecommunication antenna networks. A network that you use daily on your cellphone.

Part 1: System station, Part 2: Power Amplifier and Part 3: Antenna

The following 25 minute video shows the teardown step by step with explanations, high resolution pictures of content is further down this post.

In the above pictures we see the tuning cavities of the band pass filter for the transmit and receive channels for the antenna connections. There is a total of three separate diplexers. Each diplexer / filter consists of a, from the left, receiving band pass filter and in the middle transmitting band pass filter, these two share the same antenna connection. At the right is another receiving band pass filter that has its own antenna connection.

The tuned cavities are machined in a whole piece of aluminium and silvered on the inside. The tuning pins in the top plate are all round brass pins and additionally there is a stepper motor attached to copper metallized plastic parts that can adjust the phase shift or filter response, this is not completely clear to me.


In the above pictures we see one of the three RF amplifier boards, there is a total of three of these boards. The board itself is a Aluminium Silicon Carbide heat sink on which all the components are directly mounted. The input connectors in the bottom of the pictures leads the signal through a small preamplifier (two screws on each side of a unmarked black package) and RF circulator to the NXP BLC6G22L-40BN integrated RF LDMOS which is a 2.2GHz 40 Watt amplifier. From here the signal is routed via another RF circulator to the Anaren Xinger PICO JP503S coupler where it distributes to the two output amplifiers. The last stage of amplification is handled by two BLC6G22L-150BN Power LDMOS transistors which are 2.2GHz 150 Watt transistors, but in this setup used for a combined 60 Watt output of the module. The output RF circulator is  lead the signal to the output connector to the diplexer and any return signal is lead into a built in 50Ω attenuator.

In the above pictures we see the digital/analogue signal processing board with the two optical inputs in the top right side of the picture. Digital data is processed by the Freescale / NXP MCP8347 PowerQUICC II 667 MHz CPU and its associated Xilinx Spartan II FPGA. Translation and splitting of the telecommunications protocol data and selection of different drive modes, if the amplifier is used for GSM, EDGE, HSPA, WCDMA or LTE, is done by the main computer setup described here. The digital to analogue for transmitting and analogue to digital for receiving is handled by the following setup.

Receiving of data from the antennas are processed through the NEC 4377408 marked IC, that are impossible to locate any data on, they do however have great resemblance to the special Nokia Siemens Networks marked CPUs I have seen in other GSM/EDGE amplifiers. These handle the standard telecommunication protocol packaging and possible encryption of the digital datastream that comes from the two Analog Devices AD9238 12-bit 64MSPS analogue to digital converters that translates the analogue signal from the filter into a digital data stream.

Transmitting of data is handled by a Altera Hardcopy II, HC220F780NAK, ASIC that translates the telecommunication protocol into a digital datastream that is fed to the Analog Devices AD9787 digital to analogue converter that has a speed of 800MSPS, from here the signal is led to the power amplifier board.

Between the system boards receiving part described above and the diplexer, is a signal processing and filtering board. The lower part of the board consists primarily of power supplies spread around a Lattice MachXO LCMX0640C that is a controller between CPLD and FPGA.

In the middle of the board, there is a shielded area that distincts itself from the 3 filtering areas. A NXP Coldfire MCF5208 166 MHz 32-bit CPU with DDR RAM and 10/100 ethernet controller is mounted along side a DDR RAM IC and a ISSI IS42S16160D 64 MB 166 MHz SRAM.

Each filter area consists of two channels that runs through carefully impedance matched paths between the small amplifier ICs and Anaren Xinger PICO 1P503S 45W and Anaren Xinger II XC1900C-03S 160W couplers. 

The filters seems to be designed for more than one frequency running along side another signal or more phase shifted signals of same frequency.

In the above pictures we can see the power supply board that is mounted above the filter board and this primarily supplies power to the 3 amplifiers.

It is a Emerson power supply board rated at 48 VDC / 28 Ampere.

All shielding on the boards are neatly done with small spot welded boxes that are fixed in closely spaced clamping holders that reminds of small fuse holders. All the shield is easily removable by a small raised slit in the top of it, like a little handle, not a single shielding part was soldered to the board.

It is sensitive signals paths actually handling the RF signal, controllers and the magnetics of power supplies that are shielded individually.


Frequency bands: 700, 800, 850, 900, 1800, 1900, 1700/2100, 2100, 2300 and 2600 MHz.

Maximum capacity: Up to 6+6+6 GSM or 4+4+4 WCDMA or 1+1+1 LTE at 20 MHz or flexible combination of the above technologies in concurrent mode.

Multi-radio configuration: 1 Flexi 3-sector RF module + 1 system module for GSM/EDGE + 1 system module for WCDMA/HSPA and LTE. Remote Radio Head (RRH) solution also supported.

RF power amplifier technology: Multicarrier power amplifier (multi-standard)

Height x width x depth: 133 x 447 x 560 mm per module, indoors and outdoors. Fits in any 19” rack.

Weight: 25 kg per module

Operating temperature range: -35 °C to +55 °C

Power supply: 40.5 – 57 VDC, 184 – 276 VAC with power module

Typical power consumption: 790W for combined GSM and WCDMA site

Output power: 240 W per RF module or 40 W + 40W per Remote Radio Head (RRH)

Ingress protection class: IP 65

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Kone elevator 45 kW motor drive teardown

This is a Kone KM997160 variable frequency motor drive that is developed and used for elevators. 

Kone has a long history of their own motor drives that came in more or less atypical enclosures compared to other variable frequency drives. With this KDM model, they do however take the same form as many other drives by other manufacturers, which could lead to the assumption that these are made by a contractor and are just controlled by Kone’s own software and safety systems.

In the following pictures we see the complete unit that is about 1 meter tall and weighs somewhere around 70-80 kg. Full plastic front without any form of interactive interface or display, just 3 status LEDs that shows power, error and running.

From the specifications sticker on the side, we get the following information:

Input: 400V, 3~AC, 50-60Hz, 71A

Output: 0-Uin, 3~AC, 0-250Hz, 90A

Power: 45kW: 400V / 60HP: 400V

Taking a look under the hood we first see the DC bus capacitors at the top, the gate drive control board and underneath the black plastic cover we find the CPU.

The 4 identical metal plates that can be seen is the mounting plates for the SKiiP IGBT modules. The 6 red boxes with wires going through is the current transformers and the wires with yellow cable shoes goes to the chokes underneath the power electronics.

Two of the IGBT modules are used for AC to DC input stage with active power factor correction. The last two IGBT modules are used for outputting the variable frequency supply for the motor. The two large capacitors at the top are for the DC link.

Altera Max II EPM240/G/Z  is a low cost CPLD with 240 logic elements, 80 user defined I/O and 8kb of memory available at a internal clock frequency rate up to 300 MHz.

Atmel AT91SAM9260 ARM-based Embedded MPU. 180 MHz ARM processor with 8 KBytes Data Cache and 8 KBytes Instruction Cache. 

Semikron SKiiP 39AC126V2 IGBT module, a 3 phase bridge inverter module developed specifically for use in motor drives up to 45 kVA / 30 kW. Two of these modules are used in parallel or interleaved in this motor drive to reach its rating for a 45 kW motor.

It is a 1200 VDC module with a continues rated current at 157 Ampere, with pulsed currents up to 280 Ampere. A very fast module with a combined switching on/off time of only 720 ns. The SKiiP packages are however a pain in the ass to salvage from equipment where they are stuck to the heat sink through sticky compounds. When the screw, holding the IGBT and contact points in place, is removed, then there is only the thin aluminium bonding wires keep the silicon chips together with the enclosure, and these breaks very easily as if can be seen in the pictures.

The power factor correction choke and output chokes from Epcos are all mounted in a tray and have been wholecasted in blue epoxy, which pretty much makes it impossible to salvage for use in something else and not even the cores are possible to get free in one piece. The filter assembly is rated for 480V at 76A.

The two DC link capacitors 70CPE00150 from Kemet at each at 700 uF and 800 VDC. I have not been able to find a datasheet for these, but a guess from their physical size compared to other Kemet DC link capacitors and the ratings of this motor drive, they are properly good for about 50 A RMS each.

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Kaizer DRSSTC IV – a high impedance primary circuit experiment

A new article has been added that describes the thoughts, design, construction and test of a very high impedance primary circuit QCW DRSSTC, where the voltage ramp is coming straight from half wave rectified mains supply and a mains synced interrupter is used to trigger at the right interval.

The article covers the fall pits and strange behaviour of Tesla coils driven in this manner.

The project is highly experimental and the results were not as satisfying as expected, but problems with switching transients was a much bigger issues than initially thought of.

Read it all, see all the pictures and view all the videos at:

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A new dedicated high voltage forum!

Hello everyone!

The comment sections on my website have grown long with questions, advices and solutions. So I have expanded the site with a brand new forum, on a dedicated domain.

We are a group of seasoned high voltage and electronics enthusiasts that have created a new high voltage forum and community. A modern forum software with all the possibilities there lie within a modern frame work like that.

I am hereby inviting you all and hope to see threads with your questions, your Tesla coils, your projects or what kind of things you have to write about in the forums designated categories.

This is a good chance to be among the first and help build a vital community where new people feel welcome, get help, learn and in the end become those that help others.

Join us at

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Teardown video of HP SureStore DLT 818 tape backup station

The HP SureStore E DLT Autoloader 818 is a cost-effective high-performance tape storage solution. This system comes equipped with a DLT8000 drive, which transfers data at up to 12 MB per second (compressed), allowing servers to be backed up or restored in a matter of hours. HP libraries feature automated operation through software to eliminate the possibility of missed backups. Simply schedule backups for a convenient time and let the HP DLT8000 library do the rest, using best-in-class storage management software to support unattended “lights-out” operation. HP DLT autoloaders are designed for simplicity, both for users and system integrators. They feature a front-panel display for diagnostics and status reporting, and they use removable six-slot cartridge magazines for quick, easy media loading. The autoloaders include proven HP mechanisms and HP-tested DLTtape media for high uptime levels and reliable operation. Choose either the standalone deskside configuration, or mount up to two libraries side-by-side in a 19-inch rack.

Product Description HP SureStore DLT Autoloader 818 – tape autoloader – DLT – SCSI
Device Type Tape autoloader – DLT
Recording Standard DLT8000
Enclosure Type External
Interface Type SCSI
Total Storage Capacity 320 GB (native) / 640 GB (compressed)
Removable Media Capacity 8
Supported Tape Drives DLT
Dimensions (WxDxH) 22.1 cm x 55.9 cm x 17.7 cm
Weight 18.6 kg
Storage Removable DLT
Storage Removable Capacity 40 GB (native) / 80 GB (compressed)
Supported Tape Cartridges (Read and Write) DLT
Data Transfer Rate (native) 6 MBps ( 21.1 GBph )
Data Transfer Rate (compressed) 12 MBps ( 42.2 GBph )
Power AC 110/220 V ( 50/60 Hz )
Manufacturer Warranty 3 years warranty


Device Type Tape autoloader – DLT
Recording Standard DLT8000
Enclosure Type External
Interface Type SCSI
Total Storage Capacity 320 GB (native) / 640 GB (compressed)
Removable Media Capacity 8
Supported Tape Drives DLT
Built-in Devices Status LCD
Enclosure Colour White
Width 22.1 cm
Depth 55.9 cm
Height 17.7 cm
Weight 18.6 kg


Type DLT
Capacity 40 GB (native) / 80 GB (compressed)
Supported Tape Cartridges (Read and Write) DLT
Recording Standard DLT8000
Data Transfer Rate (native) 6 MBps ( 21.1 GBph )
Data Transfer Rate (compressed) 12 MBps ( 42.2 GBph )
Average Seek / Access Time 60 sec


Interfaces 1 x storage – Fast Wide SCSI – 68 PIN VHDCI (Mini-Centronics)
Connections 1 x storage – Fast Wide SCSI – 68 PIN VHDCI (Mini-Centronics)


Media Included Qty 6
Cables Included 2 x SCSI cable
1 x SCSI terminator
MTBF 200,000 hour(s)
Package Type Retail


Type Power supply
Voltage Required AC 110/220 V ( 50/60 Hz )
Power Consumption Operational 150 Watt


Software Included Drivers & Utilities


Service & Support 3 years warranty
Service & Support Details Limited warranty – parts and labour – 3 years – on-site


Min Operating Temperature 10 °C
Max Operating Temperature 40 °C
Humidity Range Operating 20 – 80%
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Mysterious failure of a Siemens mini circuit breaker C6A (5SY41)

From one day to another this mini circuit breaker stopped working, I had been using it wrongly as a on/off switch and was wondering if there was a mechanism inside to disable it after too many on/off switches, as MCBs are only rated for a finite number of operations.

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Teardown video of Eaton PowerWare 30 kVA UPS

Here is a video from taking apart 3 UPS units from Eaton PowerWare, these are 30 kVA units that was previously described in pictures and text in one of my earlier teardown articles: 

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Teleste AC2000, teardown of a 862 MHz cable TV amplifier

This Teleste AC2000 is a cable TV amplifier that is configurable through different insert jumpers for setting up attenuation/equalization, diplex filters, return amplifier or a transponder making it remote controllable.  This is a dual 39 dB amplifier in the range from 5 to 862 MHz which enables it of delivering 110 channels. 

This particular amplifier is set up for one input, a bypass for next amplifier in the chain and two outputs. There is no transponder installed.

These small amplifiers are used in houses where it is not practical to use a receiving antenna to get the signal from the broadcast headend transmitter. They are called a “service drop”

Instead CATV is used, short for community antenna TV, a large receiving antenna is used, a cable connection runs out to every house in the neighborhood and each house has one of these amplifiers. The return path amplifier can also send some of the signal back into the line to keep the signal good enough for the next house.

It is installed in a weather proof enclosure meant for outdoor wall installation where it is most practical to have the antenna input cable come up from the ground and from there on route cables into houses and apartments.

The internal power supply has a input voltage range from 27 to 65 VAC/35 to 90 VDC and has two output voltages. 24 VDC at 1400 mA maximum and 12 VDC at 900 mA maximum. 

The manufacturer specifications of this cable TV amplifier

  • 2-3 outputs by internal splitting
  • Spectrum analyser function
  • Plug-in module adjustments
  • Fixed station memory for electrical identification
  • Electrical gain & slope control modules
  • Optional high performance return amplifier
  • Downstream signal path 85…862 MHz (110 channels)
  • Input attenuator control range 20 dB
  • Input equaliser control range 25 dB
  • Mid-stage slope 8 dB
  • Flatness ± 0.4 dB
  • Upstream signal path 5…65 MHz

If transponder was installed:

  • US ingress monitoring
  • Return path ingress switches ON/ -6 dB / OFF control
  • 65 VAC voltage measurement
  • Local DC voltages, 12 V and 24 V
  • Temperature measurement
  • Gain and slope controlling in ALSC mode
  • Individual channel level measurement (AC6951)
  • Spectrum analyzer function
  • Lid status monitoring
  • Local connection indication at server
  • Configuration data stored in main board eeprom (station memory)

Attenuators, for all TVs manufactured after 1995, the signal strength at the TV should be between -10 dB and +15 dB, this is achieved with 20 dB range on inserts in this amplifier.

Equalizer or also called slope, is the difference in signal strength between the highest and lowest channels. This is also handled with inserts in a 25 dB range for input and 8 dB for mid-stage. To get a frequency response of ± 0.4 dB, also called flatness.

Attenuators and equalizer inserts are for the most a plastic container with the following content, a gold plated 3-legged 2-3 resistor setup.

A diplexer is a passive device that implements frequency-domain multiplexing. Two ports (e.g., L and H) are multiplexed onto a third port (e.g., S). The signals on ports L and H occupy disjoint frequency bands. Consequently, the signals on L and H can coexist on port S without interfering with each other.

The heart of this box is the CATV amplifier modules which was the popular choice of silicon in amplifiers of this type from the 1990’s.

Features of these hybrid amplifier modules for CATV systems operating over a frequency range of 40 to 450 MHz at a voltage supply of +24 V and intended for use as a line-extender.

  • Excellent linearity
  • Extremely low noise
  • Silicon nitride passivation
  • Rugged construction
  • TiPtAu metallized crystals

 The internal construction of the hybrid amplifier module can be seen below.

Close-up of the six transistors in the module.

Video with explanation of the different parts while the amplifier is being taken apart.

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