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
Making the USBDevice work …
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 …
EIP 545B RF Frequency Counter - Firmware
This part will focus on the analyze of the firmware I made so far, in order to fix a few issues I have encountered in my unit, as related in previous previous part.
It will be updated as I make progress on disassembling and understanding the firmware.
Original Firmware
The …
EIP 545B RF Frequency Counter - Part 6
Band 3 Sensitivity
I have been trying to figure out a bit more about the sensitivity problem described in part 3.
The main problem remains the first YIG sphere that has fall off the holding rod. I have tried to manipulate it with thin wood stick, under my cheap USB …
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.
Low Fequency Section
If the …
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 …
EIP 545B RF Frequency Counter - Part 5
Thanks to HighPrecision, I've been able to get a copy of an old version of the EIP documentation "Additional Service Information for 5XX CW Counters". It's unfortunately unavailable online, still, it contains a lot of valuable information.
The part dedicated to verifying the Band 3 Microwave Converter (A203) is as …
EIP 545B RF Frequency Counter - Part 4
This part is about my attempt to modify the firmware to "fix" the problem of weird intial setup: a -160MHz offset and a resolution set to 5 digits.
In the previous part, we figured some probable spots in the firware where these default setup configurations might be set.
EPROM checksums …
EIP 545B RF Frequency Counter - Part 3
Default settings
One of the annoying thing with this 'SPECIAL' edition of the firmware are the default settings:
- Frequency Offset -160MHz
- Resolution 5 digits
One of my goals while disassembling the formware was to 'fix' these defaults settings. I was wondering wether they where located in an undocumented part of …