While looking through ebay, I found the ad below. I had previously purchased 2 7A16P plug ins which I really liked using and this unit had 2 more so the starting price wasn't too bad. The $75.00 shipping seemed high but I was to find out later, it wasn't bad at all.
In the late 70's, I had taught a test equipment class that had a section on analog to digital converters and the fastest one at that time was a scan converter. In fact, the exact one used in the 7612D. I was hooked and placed the $25.00 bid.
TEKTRONIX 7612D PROGRAMMABLE DIGITIZER
YOU ARE BIDDING ON AN USED TEKTRONIX 7612D PROGRAMMABLE DIGITIZER. POWERS UP OK AND SEEMS TO BE IN GOOD WORKING CONDITION. BUT IS NOT FULLY TESTED due to lack of product knowledge and proper equipment. SOLD AS IS. S&H $75.00 to contiguous continental USA Only!!!! Payment may be made via paypal or money order.
I later won it. I paid through Paypal and then began the waiting. As I waited, I searched the internet for manuals and a short time later purchased a 2 manual set from Artek media. Less than 2 hours later I had 2 printed manuals in hand and was studying what I had purchased.
7 days later, the FedEx guy came wheeling a huge box to my door. After signing for it, I lifted it and almost dropped it immediately. This thing had to weigh about 70 pounds! Now I saw why the shipping was $75.00 and probably was a deal at that.
Removing it from the box, I couldn't believe the size of the monster. If I had known how large it was, I probably wouldn't have bid on it.
Moving it to a table because the workbench wasn't large enough, I examined it. To my surprise, it still had unbroken Lockheed Martin calibration seals over the screw heads on the sides, top, and bottom. This hadn't been opened recently! This was beginning to look promising.
Removing the top, it looked like new inside. No dirt or dust anywhere. It is almost unbelievable how much electronics is inside. I can see how this was the state-of-the-art in it's time. Connecting a power cord, I fired it up. A large fan in the back wound up to speed and the displays lit up. This was looking even more promising.
Next I needed a monitor. The 7612D has X-Y-Z outputs on the back. I wheeled my 7904 over and connected it in the X-Y mode. After some fiddling around I had a trace. Operating the buttons seemed to make everything operate in the expected fashion. Hooking up a signal generator, I began to try to get a meaningful trace.
Although it operated fairly intuitively, it was different than a scope. One of the settings was the record length which was the number of samples it was going to take and the other main one was the sample interval. That was the time between samples. After a few false starts, I had the display below from the "A" sampler. There is a plug in for A and one for the B sampler. I haven't had time to check out B yet but I am inclined to believe it will work also.
Here's a picture of it operating using a "proper" XYZ monitor.
Stay tuned for more as I learn how to operate it.