As an example of just how useful X-Ray can be when reverse engineering a sealed product......
The Hewlett Packard Logic Dart was a very clever little Logic 'analyzer' with just 3 channels. It was a graphical logic probe really but HP made a nice job of its design. The calculator and test equipment departments joined forces to design the instrument.
The probes that connected to the Logic Dart were a custom HP part and after the production of the Logic Dart ceased the leads became much in demand as they are the most likely part to break. The price of the lead sets has risen steeply in recent years due to rarity. It is not uncommon to see them sold for over £100 set.
When I first bought my Logic Dart, it was new but without the test leads. It was long believed in the HP user fraternity that the Logic Dart leads contained custom electronics and that rendered the Logic Dart useless without them. I am not one to believe such stories until I have proven it to myself. I dismantled the Logic Dart and found the three input channels were pretty much complete. There couldn't be that much in the leads surely ?
To cut a long story short, I got a chap to measure his Logic Dart leads with a multimeter to detect continuity or resistance. The results were not as useful as I had hoped. I did establish that the leads formed a potential divider with the Logic Dart's input resistance at the chassis socket. I designed what I thought was needed and it worked so I was happy. I released my findings to the HP fraternity. People could now make their own leads.
I later managed to buy a set of the Genuine HP leads and immediately placed one in an X-Ray machine

To that point in time, no one was willing to dismantle their precious probe leads as it would likely ruin the them, and they are too rare for that. I managed to get some decent images of the probe head and plug of the lead.
There were indeed components in both, but it was a very simple design and I was pleased to see that my design was correct in all aspects except I had omitted a diode. I had thought of needing a diode but had not been certain it was needed. The diode is in series with an excitation feed for Resistance tests and protects the Logic Dart from reverse voltage feeds. There is already a series protection diode inside the Logic Dart though so this is an HP belt and braces approach.
Anyway, the X-Ray images were good and they were made on an Industrial MicroFocus system.
I have just repeated the imaging using my MX-20. The images wipe the floor with those I made several years ago.
I include my latest images here. you can clearly see the dual diode package.