Hi Dave , My name is Vasile and i am an electronic hobbyist from Romania. I enjoy repairing and restoration of old test gear.
My last work that is still in progress is the complete restoration of an frequency counter Made in Romania. If a will win any of this Keysights a promise that will be apreciated and use at their maximum potential. Also it's realy hard to afford new test gear in Romania...
I'm working at 2 almost identical units but only one is 99 % finish.
Lets start.
The units look like this before a start working :
And the final first one :
Thsi project start with the input board which was not working ... as you can see the original PCB , construction, etc was a mess, even a diy job will look beter .. so i decide to redesign the PCB and keep the original schematic.
Before :
and after :
After this job a decide ... why not all board ? a few week later the PCBs arrived and continue to work.
The power supply is the only block witch not contain the original schematic, i redesign this block with modern components.
before :
And after :
The main digital board :
Original design was based on SN74S196 as first counter. Because of political in communism the import of components was stopped and they redesign the first counter with 2 K532IV9 ( the soviet version of SN74S112 ). Unfortunately none of the units have this obsolete IC. Someone replace it with a 7490 and not did a nice joob. Also the original design use Cathodeon 10 Mhz Ocxo, but soon this was replace with Unitra 5Mhz ( not bad !!! ). But they "forgot" to redesign the divider... so the modification was made by cutting traces and a lot of solder . I added the option between this 2 with only 2 jumpers.
Over all the pcb design is a mess and also a shame ...
Before :
And after ( not many pictures ... i forgot ... and the time is ticking )
The OCXO boards. A manage to find a 10 Mhz one.
Before :
and after
Some more pictures from restoration :
I stop here for now. After i will finish both of them i will make a post with more pictures, details, schematics, and so on.
Ps: The pictures are attached on postimage.cc host , i did not what to load Dave's server, so a hope anyone can see the pictures.
Good luck ! Vasile