Category: Electronics

Rigol DM3058 firmware upgrade – post mortem

This item documents a failed attempt to perform a firmware upgrade on a Rigol DM3058.

By the book

The process attempted to upgrade the firmware from v2.02 to v2.03 using the method described by Rigol and upgrade file from their official website.

There were not power interruptions during the upgrade which hung and was shut down after an hour. I might add that I had just upgraded two other DM3058s using the same method, same USB stick.

Email was sent to Rigol Support for help, none came. No surprises there, Rigol are a Chinese company.

I have later found comments that the upgrade may fail if Rigol UltraSensor has been used on the instrument. Others comment on difficulties working with some USB sticks.

The firware is loaded into a flash (external) memory chip attached to a ADSP-BF531 processor chip.

Above, the 4MB flash memory chip branded Spansion, later to become Cypress, then Infineon. Continue reading Rigol DM3058 firmware upgrade – post mortem

Last update: 13th November, 2023, 3:12 AM

Ongoing MR16 LED failures & purchasing frustrations

We have around 25 MR16 LED lamps, half of which are almost never used, the other half probably average 4 hours per day, or ~1500 hours per annum.

Remember that greens touted this ‘green technology’ to have a life of 100,000 hours. More recently, claims have been moderated to 10,000 to 25,000 hours… but that is a single LED element alone, not a set of them, and it does not include failures of the internal and external drivers. IOW it continues the fraud of green lighting.

Above, the MR16 50mm LED lamp. Continue reading Ongoing MR16 LED failures & purchasing frustrations

Last update: 12th October, 2023, 4:52 PM

LED plate driver failure #2- 24W round plate

This article documents a second failure of a 24W LED oyster. The luminaire was purchased complete on eBay for about $45.

After about two years use, the light became sensitive to switching transients on the mains, visibly blinking when other appliances were turn off or on. After some time, this progressed to oscillating on and off for a few seconds on a cold startup, but on hot startup it was stable.

These are exactly the same symptoms as the first failure… no surprises, it is the same driver board that had a faulty capacitor replaced… and worked fine for a couple of years.

Above is the failed driver board with the replaced 105° 6.8µF input filter capacitor (at the right). The capacitor should have an ESR around 5Ω, but now cannot be measured by my ESR meters (both upper limit ~100Ω). The other capacitor also has excessive ESR. Continue reading LED plate driver failure #2- 24W round plate

Last update: 27th October, 2023, 12:48 PM

Measurement of various loss quantities with a VNA – a worked example

This article documents a worked example of the matters discussed at Measurement of various loss quantities with a VNA.

Above is an air cored solenoid of about 20µH connected between Port 1 and Port 2 of a NanoVNA-H4 which has been calibrated. The whole lot is sitting on an inflated HDPE bag to isolate the DUT from the test bench. Continue reading Measurement of various loss quantities with a VNA – a worked example

Last update: 19th March, 2024, 7:17 PM

Measurement of various loss quantities with a VNA

Loss, Insertion Loss, and Mismatch Loss terms pre-date VNAs and S parameters, but a VNA can be a very productive way of measuring / calculating these quantities for two port networks.

This article explains the basic S parameters and their use to measure and calculate Loss, Insertion Loss, and Mismatch Loss.

S parameters

Review of s parameters of a two port network.

Above, a two-port network showing incident waves (a1, a2) and reflected waves (b1, b2) used in s-parameter definitions. (“Waves’ means these are voltages, not power.) Continue reading Measurement of various loss quantities with a VNA

Last update: 2nd September, 2023, 10:38 AM

Definitions of important loss terms

Readers of my articles occasionally ask for explanation of the distinction between meanings of:

  • Insertion Loss;
  • Mismatch Loss;
  • Loss (or Transmission Loss).

These terms apply to linear circuits, ie circuits that comply with linear circuit theory, things like that impedances are independent of voltage and current, sources are well represented by Thevenin and Norton equivalent circuits. Continue reading Definitions of important loss terms

Last update: 30th August, 2023, 10:28 AM

Programming a PIC 12F510 using the DIY-150 programmer

A correspondent asked how to program a PIC 12F510 used in one of my projects using his DIY-150 programmer.

The DIY-150 programmer is quite an old design and there has been no development for more than 10 years, meaning no new chips added, though there are lots of online sellers of the now stale design.

The 12F510 is very similar to the 12F509 which microbrn v150807 does support. The 12F510 can be programmed by selecting chip type 12F509.

Alternatively, download the archive below and extract a modified chipdata.cid file which includes a 12F510, and extract it to replace the existing installed file.

The revised chipdata.cid can be downloaded here: chipdata.7z.

Last update: 11th April, 2023, 6:43 AM

(tr)uSDX IMD performance

(tr)uSDX uses less common techniques for generation of an SSB telephony signal at modest power (a few watts).

There are aspects of the techniques that might raise questions as to how well they work, questions that do not seem to be addressed by the developers.

Wide signal / distortion reports

Whilst there are lots of videos where users demonstrate making QSOs with the (tr)uSDX, credible evaluation of common reports of wide transmit bandwidth is scarce, though spectrum displays of excessively wide (tr)uSDX signals on air are not so rare.

One simple objective measure of IMD is that of a two tone test with spectrum analysis.

Two tone test with spectrum analysis

A two tone test calls for combining two equal amplitude non-harmonically related pure sine waves and feeding that to the transmitter input, and observing the spectral distribution on a Spectrum Analyser.

Ideally, the output should be just the two input components frequency shifted by the virtual carrier frequency (in the case of USB). Practical transmitters are not perfect, so there will also distortion products, and a common measure is that of the 3rd order mix at  If F1 and F2 are the frequencies of the two tones (at RF), the third-order distortion products occur on both sides of these tones at 2F2 – F1 and 2F1 – F2.

Above is a figure from an Anritsu application note showing a wider scope of IMD. Distortion products are measured wrt to each of the desired signals or ‘carriers’, and this value is often given relative to those signals as dBc. (The ARRL uses a different method, referenced to two tone PEP.) Continue reading (tr)uSDX IMD performance

Last update: 28th February, 2023, 6:22 AM