Agilent 53152A 46GHz frequency counter teardown and repair from The Signal Path:
In this episode Shahriar investigates a faulty Agilent 53152A 46GHz frequency counter. The instrument does not power on and shows no sign of internal voltage presence. Teardown of the instrument reveals a large PCB where all analog and digital circuity is contained. The power supply module is a module components and upon measurements shows no activity.
The power supply is a simple switching architecture with functioning input rectifier and capacitor filter. By using an oscilloscope it is clear that the power supply PWM controller attempts to start. However, the main power supply pin shows unstable voltages indicating inadequate charge retention on the rectifying capacitor. Replacing the capacitor revives the startup condition and the power supply function returns. The PWM controller and main switching transistors are also replaced with new ones. After this repair the unit powers on and passes all self-tests. The unit can successfully measure signal frequencies and power.
I recently purchased a BSide ACM03 Plus clamp meter so that I could do some high current measurements for my tab welder project. This meter can be bought on eBay for around $25, which makes it one of the cheapest Hall effect clamp meters on the market that is capable of measuring both AC and DC current.
Since this is such a cheap meter, I wasn’t expecting much. But it actually feels really sturdy in hand and the construction looks reasonably solid, which is certainly a good start. It came with a nice little black pouch inside a non-descriptive cardboard box. It even includes a decent product manual.
Kerry Wong did a teardown of a battery adapter for the Sony A6000 mirrorless digital camera and measured the poweroff current draw of the the camera:
With the battery adapter on hand, I decided to take a look at what’s inside and then use the adapter to measure the power-off/stand-by current of the Sony A6000.
I was not expecting to see much inside this battery adapter. After all, all it needs is the connection between the battery terminals and the input power jack and a resistor between the center pin and the ground in place of the thermistor that is used to sense the temperature of the battery pack. At the most, it might also include a reverse polarity protection diode.
But a quick measurement suggested that there must be some active components inside as the adapter itself draws around 17 µA current when connected to the power source. So clearly, there is some active circuitry inside.
Upon opening up the battery adapter, I was surprised to see the circuit board inside.
The CMOS version of the commercially significant 6502: a processor architecture which launched the personal computer era.
This particular version was plucked off of an embedded industrial controller… a place where this processor still finds design wins.
The Dallas Semiconductor DS1284 (and related DS1286 which integrated a battery and crystal in the same package) found lots of use in industrial control and test equipment.
30 years ago processor chips contained not much other than the processor. Utility functions such as real time clocks, non volatile ram and watchdogs were always external.
Dallas semiconductor was quite successful in creating some of these utility chips which put a number of functions into a single device. The company was eventually acquired by Maxim in 2001.
In this episode Shahriar explores the principle operation of automotive FMCW radars. Thanks to a donated automotive radar module, various components of the system can be examined and explored. The PCB reveals three die-on-PCB ASICs responsible for generating and receiving 77GHz FMCW signals coupled to a 2D array of antennas. Several microwave components such as rat-race couplers and branchline couplers can also be observed. PCB rulers from SV1AFN Design Lab also show these microwave components at much lower frequencies. Two other ICs are used for ramp generation and PLL as well as a multi-input LNA/PGA/AAF with 12-bit ADC for IF processing. All components are examined under the microscope and the frequency of operation is calculated by measuring the branchline coupler’s dimensions.
Finally a simple Doppler effect radar is constructed by using a doubler, power divider, mixer and a pair of Vivaldi horn antennas. The Doppler effect can be observed by moving an object in front of the antenna pair.