Crystal Impedance Meter Saunders & Associates 150B - Firmware wanted

[rwweichler]

Hello everyone,

the Crystal Impedance Meter Saunders & Associates 150B has been discussed here already in 2018. I hope, some of the contributors from that time still have their device and are willing and able to help me.

I had bad luck with mine. I wanted to use my instrument to get the parameters of the crystal in an Rb Standard in order to compensate the ageing and to set up the oscillator again to its specifications.

During the measurenents the blocking capacitor OC56 across +15 V and -15 V at the output stage of the measurement oscillator got a short and has drawn a high output current from the power supply. This led to a significant increase of the +5 V rail (the crowbar circuit triggered way to late), and several logic-ICs were killed. Among them are the EPROMs, too, of which I unfortunately didn't take any backups.

Now I would like to ask whether someone could provide me the EPROM files from his/her instrument. I'd really appreciate a positive feedback. Everything else is still available at moderate costs from eBay and Digi-Key, but without the firmware I won't be able to get the unit running again.

My instrument has been made probably in 1980, and the FW version 1700 is quite old. I wouldn't mind about other FW versions. From what I've learnt, the FW versions relased over the time are compatime with the HW versions. Even the FW used in the successor model 150C should be working.

If you are interested, attached is are the screenshots of the digital and analog PCBAs with the location of the broken capacitor. I found another leaky one, it might be an idea to check them all.

Thanks so far and kind regards,
Rolf