Hi, welcome to a new voltlog, today we’re going to teardown something interesting. As you can see on my left I have this huge antenna / radio assembly which btw weighs approximately 25 Kg so it’s not easy to handle in my small lab, in fact it takes up most of my bench so I will probably do the teardown on the floor.
This antenna is called Gigabeam Wifiber and it’s manufactured by a company called Gigabeam Corporation that went bankrupt in 2010. The system is supposed to act like a transparent access point offering gigabit links over radio where fiber infrastructure is difficult to implement.
The radios operate in the 71-76 and 81-86 GHz radio spectrum bands and the modulation format is BiPhase Shift Key (BPSK). They have a transmit power of 20 dBm which translates to 100mW and that is not really a great deal of power but the antenna has a large gain of 50dB. The system takes a gigabit fiber input and on the other side from the receiving antenna you get a gigabit fiber output.
I have a pair of these, one of them is broken and I’m going to attempt to find the fault and maybe fix it. I’m hoping the problem is somewhere in the power section because that will be an easy fix because otherwise I don’t have a spectrum analyzer to take a look at the different RF stages.
Anyway In this video you are only going to see the teardown but that should interesting on its own because I expect to see lots of RF magic inside and interesting system design.
Also checkout the high res photos below:
Here is a list of the components I managed to identify inside the unit:
SMT4004: integrated programmable voltage manager IC which can monitor and control up to 4 independent supplies.
Texas Instruments OPA725: low noise, high speed, rail-to-rail op-amp.
Analog Devices AD8604: quad rail-to-rail, input and output, single-supply amplifier.
Maxim MAX4663: quad, SPST, CMOS analog switch.
IDT ICS601: Low phase noise 1 to 5 clock multiplier.
XCF04: Xilinx In-System Programmable 4 Mbit ROMs for Configuration of FPGAs.
Although the operating temperature of this LED might be up to 85 deg C, while looking through various datasheets, I couldn’t find a graph showing a plot of the expected life in hours vs temperature. If I were to guess I would say you need to run these at less than 50 degrees C to get some decent life out of them. There was a mention of a stress test in a datasheet and that meant for that particular led manufacturer running it at 60 degrees C full rated current for 1000 hours with no resulting damage.
If you have any info on these LED’s and what temperature they should be running at to get some decent life out of them, please leave a comment below.
So to finish up on this story I have to say that I learned some things about these LED strips. If I were to design something from scratch I would run some basic thermal calculations based on the figures from datasheets but in this case, with these chinese led strips, there is no datasheet, I can’t even easily compare to existing datasheet because these can’t be compared: the driving current is different, the LED only has one die in my case and so on.
The next thing I will try is to double my L shaped heatsink with another piece the same model and size this way I will be increasing my heatsink surface and hopefully cool the LED’s better, maybe shave another 5 degrees.
I will be posting an update with some measurements for comparison once I get the upgrade done. Links for the power supply, led dimmers as well as the light meter used in this video will be in the description of the video so do check them out.
EEWEb Europe is an online community for electronics engineering and electrical engineering. It is also an electronic forum and it offers electrical and electronic design articles and resources. The website language is German.
In this video I’m doing a product review and teardown of the Mastech MS6612 Digital Light Meter. I am also taking a look at a typical 9V battery datasheet and make an estimate on the usage hours that I’m going to get for this meter.
In this video I do a quick review of a 5 inch LCD TFT Monitor With 2 CH Analog Input. This module was sent to me free of charge for review by gearbest.com. The module is based on the MST703 video decoder and if you want to know more about this chip check it’s datasheet in the links from the video description.
Today we’re going to be looking at some laptop batteries, we’re going to take them apart and attempt to salvage some lithium cells to use in other projects.
I have these two identical batteries coming from a Fujitsu Siemens laptop and they’re both dead. These batteries usually fail in one of two modes, they either have a failed electronics board and in this case they don’t communicate with the laptop motherboard anymore for correct management or they have one or more lithium cells failed and they don’t reach their nominal voltage anymore.I believe these two are in the second category where one or more cells have failed and they don’t reach their nominal voltage anymore.
The assembly of this LED persistence of vision kit started well but it soon went bad because of poor design and lack of instructions. There is no documentation on how to assemble the mechanical parts so you have to figure that out yourself. There is no mention or pictures of how the LED’s should be soldered and to my surprise they need to be soldered on the edge of the PCB. There is no information on how to load the firmware or custom text patterns. After some research I did manage to find a chinese app which is supposed to work with this kit but I had no success in writing/uploading anything to the microcontroller.
I even spent an hour or so with google translate and, translated to english most of the buttons and messages in the app.
At this point I’m not sure if my problem is in the hardware(unlikely) or if I need to program the microcontroller, or if the microcontroller has some firmware and I just need to upload a custom display pattern using that chinese app.
Too much time & effort has been wasted so I’m not going to follow this anymore. My recommendation: don’t buy this kit unless you have too much free time and you enjoy solving complicated (chinese) problems.