HP 5326 Frequency Counter NixieTube Display

HP 5326, a combination Frequency Counter and DVM.

In the first part of the video, I am making an adjustment to the timebase oscillator using a 10MHz GPS disciplined oscillator as a reference. I slowly bring the count down to within 2Hz, then replace the top cover and let the instrument settle. The display is set to 1Hz resolution.
I need to find an additional nixie tube and three ICs in order to add that eighth digit to the display (Option 01).
Anyone have a junker that they would want to sell a few parts off of?

In part 2, I have already done the calibration of the DVM using a precision 5-volt reference source. I dial up the resolution of the counter to display the measurement with a 10uV resolution.

Even with just a plain-old crystal oscillator for the timebase, this is a very accurate and stable instrument.

Then again, this unit could benefit from a TCXO and I wouldn't have replace the top cover. An OCXO really is the way to go but they often have a 15-minute warmup time.

Thanks for looking