I recently decided to calibrate my HP 4195A network/spectrum analyser. While I had the device open, I also dumped the firmware (28 EPROMS!)

First of all, I made a backup of the EEPROM containing the calibration data. The EEPROM is located on the A8 assembly, which is the measurement control processor board.

Afterwards, the EPROMS containing the signal processor firmware were copied. They are located on A6:

It took quite a while to pull out all 22 EEPROMs out and read out their contents 🙂

Below is the HEX dump of the firmware EPROMs as well as my calibration data. Of course, this calibration data is basically useless for another machine than mine, but if an EEPROM lost its contents, this calibration may be used as an initial calibration, and individual parts (e.g. source or receiver voltage tuned bandpass filters) may be adjusted based on that.