Articles tagged with repair

Numworks N0110 calculator full repair

My daughter's Numworks N0110 graphing calculator got fried when plugged in a cheap USB PSU. Black screen, heating up killing the battery in a matter of a few tens of minutes.

The design being originally Open Source (hardware and firmware), it makes sense to try to fix it instead of …

HP 34970A Data Acquisition Unit - part 6

Quick follow up; I recently got back on this project to try to complete it and fix remaining problems.

The source code for the firmware is available here:

https://hg.sr.ht/~douardda/hp34970-firmware

The Kicad project is available here:

https://git.sr.ht/~douardda/hp34970-pcb

HP 34970A Data Acquisition Unit - part 5

After a loooong pause on this project, I have recently been able to work on it again. In the previous post in this series, I've started to implement a replacement board prototype based on a an NUCLEO board and an SSD1322-based OLED display.

Meanwhile, I have also almost completely described …

HP8662A Synthetized Signal Generator - Part 3

This is the part 3 on my series about my HP 8662A Signal Generator, and is about the third main problems I found with this unit, as evocated in part 2: Error 04 is lit and there are some very unpleasant spectrums at some frequencies.

HP8662A Synthetized Signal Generator - Part 2

This is the part 2 on my series about my HP 8662A Signal Generator. After fixing the PSU, several more problems needed to be addressed:

• a few sloppy keys on the keypad,
• the know did not work at all,
• and more importantly, some very unpleasant spectrums at some frequencies (covered …

HP8662A Synthetized Signal Generator - Part 1

I recently pulled an HP 8662A I bought a while ago from my cellar. I don't remember exactly in what condition it was advertized when I purchased it, but it was most probably advertized as non working (otherwise it would have been cheap enough, more, what the fun in buying …

HP3562A Dynamic Signal Analyzer

One of my old test gears waiting for my attention in the cellar was a HP 3562A Dynamic Signal Analyzer. Back then I bought this device mainly for doing audio analysis (I was building my HiFi system, mostly based on Nelson Pass' schematics), mainly to display spectrum responses and compute …

HP3562A Dynamic Signal Analyzer - Part 2

This is the part 2 of the series about my HP 3562A Digital Signal Analyzer, quickly describing the Digital Section of the instrument.

Digital Section

The unit is quite capable, since the main CPU is a 68000 (not exactly of small CPU for the time).

The 8 boards are:

• A1 …

HP3562A Dynamic Signal Analyzer - Part 3

This is the part 3 of the series about my HP 3562A Digital Signal Analyzer, quickly describing the Analog Section of the instrument.

Analog Section

The analog section consist in 6 boards:

• A30: Analog Source
• A31: Trigger
• A32, A34: Input ADCs
• A33, A35: Input

Analog Source

This board is mainly …

HP3562A Dynamic Signal Analyzer - Part 4

This is the part 4 of the series about my HP 3562A Digital Signal Analyzer, quickly describing the HP 1345A Digital Display unit as well as the repair I had to do on it.