I already commented in a previous blog that I was repairing an 54501a oscilloscope. I was impressed by the quality of its circuit and general build; but also its logic was miles ahead of what I was used with analog oscilloscopes. Moreover, you could print out a screen through HP-IB to a suitable printer (that we also have).
The 100 MHz bandwidth may sound limited nowadays, with a lot of equipment running in the gigahertz range, from calculators to computers; on the other hand, it is plenty enough for any digital or analog audio applications, and this is what I am planning to use it for. Nowadays, with the advent of the MQA audio codecs, it will be priceless to perform all kind of analysis on how different waveforms are encoded.
As I have let the unit in the mountains' laboratory, I am not able to post any pictures - but i will during this weekend. The problem this unit seems to have is that it has lost the capacity to store a calibration. It used a vram memory chip that included its own battery, and it has run dry after all these years. The solution is to unsolder the old chip and solder in a replacement. This is a 5 euro chip, so it is a quite safe investment. Apparently, once this problem is sorted, it can be self-calibrated and the new values stored. Then -fingers crossed - all self tests will pass again.
I'll keep you posted. Please also email me if you have a similar machine to repair, or are looking for similar equipment.