Repair

Repairing a "for parts" Canon 7D Mark II.

Introduction I was recently looking for a replacement for my ageing (ancient?) entry level Canon 600D. I came across a cheap 7D Mark II body (7d2 from now on) that was sold as “broken, for parts only”. This repair was a fun and rewarding experience requiring no spare parts. The Canon 7D Mark II The Canon 7D Mark II is a high-end 20.2 megapixel APS-C size DSLR that was released towards the end of 2014. It is part of their advanced/professional range of cameras and could be regarded as similar to a 5D Mark IV with a smaller CMOS. At the time of release it was positively received. The body I purchased was sold for €180 as “broken, for parts only”. Let’s hope not.

Tuesday, March 4, 2025 | 10 minutes Read

Boxfish

Introduction If you need help with: Repair of electronics Design of electronic systems Software Please send me …

Tuesday, February 6, 2024 | 1 minute Read

HP 8640B Part 2: Mains input and rectifier board replacement

Introduction 6 years ago I acquired an HP 8640B that needed work (see HP 8640B Part 1: initial state). Over the last few years, I managed to clean up the unit cosmetically, but not dive in to it any deeper. Until now. I recently found some time to work on it again and started looking at the power rails. I knew that (at least) the -5.2V rail had intermittent issues, and had noticed the caps on the AC input needed to be replaced as well.

Tuesday, February 6, 2024 | 8 minutes Read

HP 8640B Part 1: initial state

Introduction I recently acquired a HP 8640B signal generator. A quick summary of the specs shows why this is an interesting piece of equipment: 500kHz to 512 MHz (option 2 adds a doubler, extending the range to 1.024 GHz) Available power range is -145dBm to +19 dBm, within +0.5dB across the full frequency range Extremely low phase noise (less then -130 dBc at 450 MHz, 20kHz from the carrier) Fine tuning (when in locked mode): >+/-20ppm Integrated counter, switchable between the internal generator and an external input FM and AM modulation Beautifully engineered (but that’s just an opinion) The retail price in the mid seventies was around 12.000 USD (which in 2017 would be about 90.000 USD).

Saturday, June 10, 2017 | 3 minutes Read

HP 8711(A): modifications, tweaks, refurbishing

Introduction I recently acquired a fairly well preserved HP 8711A network analyser. As sold, this is an economy model, offering only scalar measurements, although vector information can be acquired through the HP-IB bus. What makes this unit interesting, is that the hardware is the same as the never released 8712A, which has vector capabilities. Some changes in the bootrom allow the user to “convert” the unit, making it behave like a full fledged VNA.

Monday, November 14, 2016 | 4 minutes Read