Blog Archives

Tura bucegi 28 octombrie 2018

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Anul asta nu am reușit sa ajung prea des la munte, asa ca duminica s-a ivit ocazia de a ieși la o plimbare

Vremea a fost specifica anotimpului, stabila, cald în pădure și pe unde bătea soarele, dar cu semnele iernii vizibile peste tot: gheata și zăpadă pana în pădure, în zonele ferite.

Era un strat fin de nori, dar nu suficienți cat sa oprească soarele

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Category: Munte

Fixing a VORTEX 32G19

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This is a quick post about fixing a TV that had the HDMI connector melted off the main board.
Got the TV as junk – so there was no pressure to fix it.

The TV’s id numbers are ( stickers on the main board / firmware, etc):
C/N: PC07035
P/N: CV028E_V5E0_01238
D/N: 20070322X00005
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Category: Repairs

General description

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While working on RF stuff I got to the point where I had to tune filters and measure frequency response of amplifiers and other tuned circuits.
This implies having access to a VNA.
As something like that is out of reach, and buying an existing one is out of my budget I started out designing one from scratch.
For that I’ve used the N2PK VNA as a starting point with some small changes that I though will be useful.

The entire system will have:

  1. Two AD9851 based generators, each with 2 buffered outputs
  2. One AD8302 based detector that measures phase and amplitude differences
  3. One system control board, that offers to the driving computer a SPI and an I2C interface

Each board has a 12V input and local LDO’s for all needed voltages.
12V was chosen because the value of the MMIC’s bias network was high enough to require just a generic inductor.
I’ve used 5V for all internal supplies as all chips used that voltage.
Also, I’ve used a common PCB template – so the boards can be stacked with M3 spacers.
That will also simplify making some shielded cases, if needed – just one case template.

The overall system architecture looks like this:

Category: VNA

New toy

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Just got a new toy, to start working on some interesting projects: an HP3466A almost my age, but still kicking

Here are some pictures:

Related Images:

Category: Electronica | Tags:

Chinese PSU fix

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This is a quick teardown and fix of a Chinese variable power supply.
While trying to measure a negative power supply I’ve discovered that the negative terminal was shorted to main’s earth and case


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Category: Electronica | Tags: , , ,

Notebook restoration

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In this post i’ll show a quick walk-trough on how I managed to re-use an old Asus A6RP that had a sad ending.
In a few words, the entire case got smashed to plastic splinters. Luckily the internal components survived.
The case was rebuilt around two 4mm transparent acrylic sheets and 2.5mm pcb stand-offs, 10 and 15mm tall.

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Category: Electronica | Tags: , ,

RGB led lighting module update

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top layer

This is an update for the led lighting project.
The design in complete and the PCB’s are almost ready.
This is the schematic:

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