Huawei RRU3928 1800MHz radio base station teardown (part 1 of 2)

The RRU3928 is an outdoor remote radio unit. It processes baseband and RF signal data. With the Software Defined Radio (SDR)technology, the RRU3928 supports the dual-mode operation of any two modes of GSM, UMTS, and LTE through software configuration modification. RRU3928 has a dual-transmitter and dual-receiver structure, which supports higher output power and carrier capacity.

It can f.ex. do 6x GSM carriers at each 10 Watt and 1x LTE carrier at 2×10 Watt or 4x GSM carrier at each 10 Watt and 2x UMTS carriers at 2×20 Watt.

This is the initial teardown and later on I will release part 2 which is the circuit analysis video.

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Nokia Siemens Flexi BTS base station teardown: Circuit analysis (part 2 of 2)

Circuit analysis of a Nokia Siemens Networks Flexi BTS base station. This have been in service as a 6 antenna GSM system for mobile telecommunications.

GSM/EDGE, WCDMA/HSPA and LTE capable. 2×40 Watt output power.

If you missed part 1, see it here:

Above picture shows the coaxial cavity band pass filter which in popular speech is called a duplexer or diplexer. For a explanation on how this works, watch the first part of the video shown here above.

The duplexer control board and front end is managed by a ARM7 TDMI microcontroller with part number TMS470R1A288PGET. It is a 32-bit 24 MHz RISC processor.

Anaren Xinger II XC1900E hybrid couplers are used for phase split before feeding into the low noise amplifiers for signal transfer from duplexer module to power amplifier module.

The last picture could possibly show the DAC used for the transmit chain. It is a TI DAC56721 which is a 14-bit DAC capable of 275 MSPS.

The power amplifier consists of a series of low noise amplifiers, general purpose amplifiers and power amplifiers. The first few amplifier ICs are not able to be identified as their part numbers are not unique.

First identifiable IC is a Freescale M005N 0.8-2.2 GHz 18.5 dB general purpose amplifier that feeds the Freescale SW7IC18100N which is a power amplifier rated for 100 Watt dissipate at 1.8 GHz.

Two output circulators is used for double protection against reflected energy from the duplexer and antenna array.

The system board main processor is a unknown TI FPGA that has a generic Nokia Siemens part number which is not identifiable. It has a Marvell Alaska 88E1111 Gigabit network controller to handle the optical network interfaces.

A Texas Instruments TI DSP IC could be used for the first stage digital to analog conversion, purely guessed on from its location on the PCB. It is the TMS320TCI100 (C64x series) with is running at 720 MHz and is able of running 5760 MIPS.

The analog to digital signal path starts with a ceramic resonator band pass filter (explained here: ) which feed into a Maxim MAX19995 dual 1.7-2.2 GHz downconversion mixer (explained here: ) which by the use of a local oscillator can bring down the carrier frequency of the signal to something lower that is easier to work with.

The two separate lines now go through the ultra low loss 21 MHz band pass filters from Epcos. The B5221 is a 172.8 MHz SAW IF filter (explained here: ) before being fed into either a ADC or another mixer, the ST PARIS part is not identifiable.

The last stage is the Analog Devices AD9218 which is a dual 10-bit analog to digital conversion IC capable of 105 MSPS.

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Youtube subscription change, please check!

Since youtube changed their notification setup a long while ago, you might be missing out on notifications about my new videos. Be sure to check if you have the “bell” clicked next to the subscription! Thank you 

Check here:

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Moving to a new lab (part 5 and 6) tour and finally its operational

Here you get a short glimpse of the new space for the laboratory and the final setup.

This is part 5 and 6 in a series of videos on moving out, moving in and setting up the new lab / work shop.

I am moving out of the apartment and into our own house, which has a room dedicated to the laboratory and a work shop for rough work.

Part 5

Part 6

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Nokia Siemens Flexi BTS base station teardown: Power amplifier (part 1 of 2)

Teardown of a Nokia Siemens Networks Flexi BTS base station. This have been in service as a 6 antenna GSM system for mobile telecommunications.

GSM/EDGE, WCDMA/HSPA and LTE capable. 2×40 Watt output power.

also a picture of me pointing at where a remote radio unit or base station amplifier is usually mounted. Technically seen this is a TMA (tower mounted amplifier)

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Eaton PowerWare 20 kVA UPS teardown

Here is a little quick, dirty and early morning junk yard teardown of a 20 kVA Eaton PowerWare UPS system.

I have earlier taken some of these systems apart and you can see the differences from there photo galleries:

File archive

File archive

File archive

Other UPS teardown videos:

Teardown of a Eaton PowerWare 60kVA UPS system

Teardown video of Eaton PowerWare 30 kVA UPS

Teardown – Eaton Powerware 30 kVA UPS

Teardown of a Merlin Gerin Pulsar ESV 22+ UPS

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GE AMX-II, mobile 110kV X-RAY system teardown

Teardown of SCR inverter controller, driver and bridge for a General Electric mobile x-ray unit, the AMX-II. Features a 120V battery operated apparatus from 1979 which has a 60 Hz mains inverter and 500 Hz high voltage inverter. All analog controlled with completely custom made electronics.

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Hameg 8122 Universal Counter – teardown, repair and test

The Hameg 8122 is a programable universal counter / timer that has 3 inputs. Channel A and B from DC-150 MHz at 300 Vp-p and channel C from DC-1.6 GHz at 5 Vp-p.

I accidentally broke a knob off the instrument when moving and while I wanted to repair it, I might as well give a teardown of the unit. Finding a replacement part was not easy, but a cheap alternative solution was found.

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15000$ (1990’s) Sony 3CCD Analogue color camera giveaway! (shipping costs apply)

As a part of Dave from eevblog gave me the opportunity to reach a larger audience through the guest videos, I hoped that I found a new owner for this camera and that it would bring something good to another electronics hobbyist. Unfortunately I did not find anyone back then, so I will give it another try.

You can have this camera for free! You only have to pay for shipping costs and be within the few rules stated further down. Visit:

It is a Sony BVP-7AP Color Video Camera which is meant to be used with the CCU-355/P, this is the central control unit that would sit in a car with the satellite dish or be mounted in the mixer room of a studio.

It has nice viewfinder and properly a good shotgun microphone. It has a Fujinon 14x motorized zoom lens. It has 3 separate color sensors, hence the 3CCD brand, they sit in a optical filter for Red, Green and Blue.

It delivers a 720×576 lines PAL encoded signal, form the test output, the combined CCU output is a mix of picture, sound and internal communication on a special carrier frequency.

It has seen some water from bad storage, which never entered the electronics, but the UV filter behind the lens seems to have some glass pest and the exterior of the zoom lens and view finder has some aluminium corrosion. But it seems fully functional.

This is a heavy item (6kg) and shipping might be in the range of 60€ for Europe (even worse overseas), cost can vary from country to country, please ask for specific price if needed.

I will also include the DVR-USB converter and the dodgy software that came with it :)

The “contest” rules

0. Watch the video to get an idea of the electronics that is inside
1. Present a short description of a project that you want to use this camera for
2. Projects that will focus on digitalizing the analogue sensors for a new purpose will be considered front runners
3. I pick the winning idea on October 1st 2018
4. Show the result  on

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Teardown of a Eaton PowerWare 60kVA UPS system

This is the teardown of a large 2x 60 kVA Eaton UPS system, first is the teardown video and below are some pictures and a little description of the components.

Here is a picture of a single 60 kVA system installed with battery and inverter cabinets

I am not quite sure if this was really a 60 kVA or a 90 kVA unit, as the cabinet had both stickers on it.

The cabinets were unfortunately badly damaged from crane handling when they were thrown out into the junk yard. I managed to scavenge input rectifier, capacitor bank and 5 inverters from the system.

The inverter boards consisted of 10x FS35R12W1T4 IGBT 3-phase full-bridge modules, 6 of them used for the output and 4 of them for the intermediate / battery charge inverters.  For details of the boards see the video at the top.

The inverter boards were pure with only IGBT and DC bus capacitors, so they are suitable for hacking into something else, maybe it is just the relatively low 70 A peak current handling of the modules that limits its use for other applications.

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