Test setup in the living
This is a 0,01 upto 32MHz , in one range, VNA. It was a gift from Nanne who used it a long time ago until it died. I had no space in my lab at that moment because on both my benches I was working on repairs for customers. So I repaired it “in style,” in the living, with a 50’s 122AR HP scope and some old analog multimeters.
The construction is from gear out this time area is often service friendly.
The sweeper was introduced in the Hewlett Packard Journal from january 1968 as “Three and One-half Decades in One Clean Sweep” A bit funny is the statement they made in several introductions from this area. Because it is All Transistor, a fan is not needed…
Dead diodes and an interesting PCB construction
Talking about heat, there are some “polished” pcb “pads” under the 2 resistors on the right. This is something I have seen in an other HP instrument from that time period. I think it has to do with reflecting the heat so the PCB does not turn brown/black
Something wend wrong here too
There were some dead ceramic caps, like the one above. The other side was even more black and had a hole in it. A lot of resistors were outside tolerance. It was not just one fault but a whole series of small problems. But the part count is low, like you see above, so very easy to check it board for board, even is it is not powered. Just removing components and test them.
together with a nixie counter
It works again but it will need some alignment so you can expect more info about this beautiful sweeper in the future.
