Understanding and repairing the power supply from a 1969 analog computer

Ken Shirriff writes:

We recently started restoring a vintage1 analog computer. Unlike a digital computer that represents numbers with discrete binary values, an analog computer performs computations using physical, continuously changeable values such as voltages. Since the accuracy of the results depends on the accuracy of these voltages, a precision power supply is critical in an analog computer. This blog post discusses how this computer’s power supply works, and how we fixed a problem with it. This is the second post in the series; the first post discussed the precision op amps in the computer.

More details at righto.com.

A look inside a Marconi signal generator

A closer look at a Marconi Instruments signal generator @ jaeblog:

Recently I got a Marconi Instruments 2019 signal generator, capable of generating signals from 80Khz up to 1040Mhz. It can also modulate these signals with AM, FM and more. This instrument is from the mid 80s and is, as far as I can test, still in good operational order.
A signal generator capable of generating over 1Ghz is pretty impressive, especially in the 80s, so let’s have a look inside this unit and see how it’s made.

Teardown of a Spex HS1000 monochromator controller

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Kerry Wong did a teardown of a SPEX HS1000 monochromator/spectrometer controller:

Monochromator is one of those things that has always fascinated me. Over the years, I have done quite a few experiments (I, II, III) with an EP200Mmd monochromator and it was a lot of fun. Because monochromators are such highly specialized equipment, decent ones are hard to come by at reasonable prices second hand. So my strategy has been to scour eBay once a while and pick up bit and pieces whenever I can.

See the full post on his blog.

Check out the video after the break.

Tutorial, experiment and teardown of a 24GHz Doppler radar module

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Shahriar posted a detailed analysis of a CDM324 24GHz Doppler radar module from IC Station:

Opening the module reveals a series of microwave PCB components and several active devices. A complete analysis of the module is presented. The unit is then measured and the impact of antenna impedance and power supply voltage on the output frequency is measured. The phase noise of the output signal is also measured. Using a series of servo motors, the radiation pattern of the antenna array in both azimuth and elevation is also presented.

More details on The Signal Path blog.

Check out the video after the break.

Inside a Datum 9300 time code generator

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Kerry Wong did a teardown of a Datum 9300 time code generator:

IRIG time code generators (not to be confused with the ones used in video and film industry) are often used for clock synchronization among various connected equipment and is commonly used in power generation and distribution industry as well as in the military. In this blog post we will take a look inside a Datum 9300 time code generator from the late 80’s. A video detailing the teardown is linked towards the end of the post.

See the full post on his blog here.

Check out the video after the break.

Electronic key tear down

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Tear down of an Electronic key  from Electronupdate:

In the mid 1980’s a company called Dallas Semiconductor was producing a wide range of small RAMs with integrated battery backup. One of the more unusual item was an early attempt at an electronic key: a user would be issued a key which could then be typically used to allow access to equipment and to keep track of usage. Not very secure by today’s standards…. but an interesting data point.
Opening it up shows that it had two major parts: a silicon die and a battery. The amount of ram on the die was very small, 256 bits!

More details on Electronupdate blog.

Check out the video after the break.

Silicon die analysis: Inside an op amp with interesting “butterfly” transistors

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An excellent in-depth look at theTL084 op amp by Ken Shirriff:

Some integrated circuits have very interesting dies under a microscope, like the chip below with designs that look kind of like butterflies. These patterns are special JFET input transistors that improved the chip’s performance. This chip is a Texas Instruments TL084 quad op amp and the symmetry of the four op amps is visible in the photo. (You can also see four big irregular rectangular regions; these are capacitors to stabilize the op amps.) In this article, I describe these components and the other circuitry in the chip and explain how it works. This article also includes an interactive chip explorer that shows each schematic component on the die and explains what it does.

See the full post on Ken Shirriff’s blog.

Siglent SDG6000X Series Arbitrary waveform generator review, teardown and experiments

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A closer look at the newly released Siglent SDG6000X Series Arbitrary Waveform Generator from The Signal Path:

The full teardown of the unit reveals the internal architecture of the instrument, DAC / FPGA interconnect as well as the output amplifier structure. Although the limitations of the FPGA prevents the instrument to operate at full 2.5GSa/s in arb-mode, the instrument is capable of providing complex modulation up to the full 500MHz signal bandwidth.

More details on The Signal Path blog.

Check out the video after the break.

My new third hand

I recently brought from Banggood a support for having a third hand during soldering operations…

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the support is made by an aluminum base and three arms which end with a crocodile clamp with insulating sheath:

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The assembly is very simple, the arms must be screwed on the base:

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In general this support is very usefulthe arms are very well articulated and their length allows to “grasp” even medium-sized cards:

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The only defect is the position of the feet, which makes the base not too stable:

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