Stock photo of amplifiers, from https://www.pexels.com/photo/guitar-stage-set-in-rock-studio-4413723/

Repairing a Little Mark III Bass Amp

I recently received a defective Markbass Little Mark III bass amp in return for fixing some other audio equipment. According to its previous owner, the amp had all of a sudden started to blow the input fuse. Turns out, the amp had undergone repair before. The power amplifier transistors had been replaced, and blobs of solder and (seemingly corrosive) flux could be found across parts of the PCB. A quick continuity measurement shows that the transistors in the class AB power amplifier and the switch-mode power supply have failed. Other than that, no apparent damage was visible. Will a simple transistor replacement bring the amp back to life?

#Hardware

Stock photo of an USB adapter, from https://www.pexels.com/photo/black-usb-cable-229543/

Cheap USB-C to micro USB Cables: Are they any good?

On the search for a simple way to flash microcontroller development boards from hosts with USB-C ports only, I came across an adapter cable that sold for less than a dollar. Would I recommend you getting one as well? No. Because the cable didn't work at all.

#Hardware

Stock photo of a blower control unit, from https://www.pexels.com/photo/traffic-industry-technology-station-6308578/

Calibrating a GW Instek GPD-3303S lab power supply

I purchased a pre-owned GW Instek GPD-3303S three-channel power supply. Its output voltages were close enough to the true value, but the currents were off by a few percent. Locating the service manual on the web was not a big problem, but the instructions did not really line up with my unit. Click here to find out how I managed to tune its settings.

#Hardware

Photo of the display of a Hama PDF20 DAB+/FM receiver

Denoising the Hama PDR20 DAB+/FM receiver

Here's another episode of my quest for a decent DAB+ receiver, this time checking out a Hama PDR20. I was (and still am) quite impressed by the fact that it comes with a single piece of wire attached to a female SMB connector as its antenna, and still yields a fairly good signal strength. So what's the problem? Well the device features two 3.5mm output connectors, both of which are outputting a nasty noise signal. Here's how to tame the beast...

#Hardware

Stock photo of a motherboard, from https://www.pexels.com/photo/black-and-gray-motherboard-2582937/

Sniffing the SMBus

There's plenty of ways to add a temperature display to a desktop computer. But capturing temperature readings from the system management bus (SMBus) isn't among the widely used techniques. As the SMBus is very similar to I2C in its nature, technically it shouldn't be too complicated to monitor (and decode) the data exchange on the board. Unfortunately, there's a bunch of challenges included here, as the hardware I2C on many microcontroller boards will only capture traffic directed to a single slave address. Here's my workaround, showing how to use a Teensy 2.0 to capture the data.

#Hardware #Software

Stock photo of adapters, from https://www.pexels.com/photo/set-of-modern-port-adapters-on-black-surface-4219861/

Peeking inside a cheap Lightning adapter

What to expect when you receive an adapter that breaks out Apple's Lightning plug into a replicated charging port and a 3.5mm audio output? The answer is: Not much audio-wise. Here's a glimpse to the inside of this thing (spoiler alert: there's not much to see).

#Hardware