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After nearly 10 years of continuous operation, my Panasonic DMR-EX77 PVR died. The display went out and it didn't respond to the remote control. Sometimes this type of failure is just a fuse which has been stressed too many times by the inrush current produced when charging large capacitors in the power supply, but not this time. It was immediately obvious that the electrolytic capacitors had failed. I could see their bulging tops which are designed to blow out in the event of failure. All electrolytic capacitors have an expected lifetime which is mainly due to the wet electrolyte drying out at which point the capacitance drops and the equivalent series resistance goes up. It seems to be a common problem with these PVRs. On this product, the capacitors which needed replacing were identified as C1401, C1402, C4056 & C1557. The service manual explains the disassembly procedure and has the schematic and bill of materials which makes finding replacements easy. I ordered spares from RS Components and disassembled the PVR carefully. Since many different types of screws are used, it is a good idea to stick them down to a sheet of paper with a note of which screw was…

I've been building up this set of equipment on my bench at home over the last few months, with some older kit reused. It's the minimum needed to do embedded development and I don't even have a bench power supply yet. I can get away without one since the dev kits are USB powered, but when I need one I have my eye on the Gophert NPS-1601 From top left to bottom right 1280 x 1024 @ 60 Hz VGA and DVI inputs, USB hub with 2 downstream USB-A. Was £360 in 2003. 13" 1920 x 1080 @ 60 Hz matte non-touch display Intel i5-5200 CPU @ 2.20GHz (Broadwell-U, 14nm, 2 cores, 4 threads) 8 GB DDR3 RAM, 256 GB SSD Liteon L8H-256V2G-11M.2 Intel HD Graphics 5500 Windows 10 Home USB3 Type A x2, Mini Display Port, 3.5mm phones/mic, SD Card slot Liteon disk results in AS SSD Benchmark 1.7 Read: Seq @ 514 MB/s, 4k @ 22 MB/s, Acc Time 0.12ms Write: Seq @ 225 MB/s, 4k @ 57 MB/s, Acc Time 0.08ms Review Reference Guide Full HD 1080p on DVI & VGA, 4k on HDMI Buy (Amazon) was £17 in 2021. Buy (Amazon) was £8 in 2016. 14…

A common problem in embedded firmware development is having to develop routines which read-in a given signal. Usually you have a sample device available which can produce the required signal on demand, but it is not always quick and simple to get this signal when you need it, and to get an exactly repeatable version of it. For example, if it is a sensor signal, then the signal will vary according to the sensed parameter (temperature, humidity, light) and will vary just due to noise so that it is difficult to get exactly the same signal twice. Even if you have the sample device and it can be made to produce the signal, it can be bulky, heavy or power consuming and so difficult to have on your desk along with your prototype hardware. Therefore there is often a need for some sort of signal generator which can act as a stand-in for the signal from the sample product during development. Starting Small At one end of the scale you have simple analogue oscillators which can produce sine, square, triangle and pulse waveforms with continuous frequency and amplitude adjustments. Whilst it is not difficult or expensive to build the simplest…

As an embedded engineer, I need to be able to see signals on the board under test in a reliable and trustworthy way. It is important to see a few signals on the same display to be able to measure time differences between them, so a multi channel oscilloscope is essential. Whilst it sounds like it would be a good idea to see as many signals as possible at once, this is only possible on a logic analyser, which reduces the analogue nature of the signals to a digital one. Logic analysers are great for multiple signals, once you are sure that the digital waveforms have the right analogue characteristics - high level, low level, rise time, fall times, ringing, spikes, noise, gitches on the edges. The logic analyser will hide all that from you and always show perfectly squared off pulses. If a logic analyser probe is connected to an input pin that isn't being driven, or an output in a high impedance state, it will pick up crosstalk from other signals on the board and you will see some unexpected pulses which the logic analyser makes look worse because it has squared them off. So you need a…