Hi Be careful about air flow. Those counters have heat issues even in the stock configuration. The Rb is a bit of a power hog so it heats up as well. Not saying it won’t work, only that you need to be sure the air is moving in the right places.
Bob > On Feb 19, 2018, at 4:18 PM, Skip Withrow <skip.with...@gmail.com> wrote: > > Hello Time-Nuts, > > A while back I acquired an HP 53131A, and a bit later added one of the > Chinese knock-off 3GHz prescalers. Makes for a nice counter except > for the very poor standard timebase. So, While researching the Option > 010 and finding how outrageous the prices are running I found an > Option 010 DIY project. It occurred to me that I could just > substitute a Symmetricom X72 rubidium oscillator for the ovenized > OCXO. > > It came out really nice (and is much better than an Option 010 - at > least for anything over 10-100 seconds). I have a header so that I > can calibrate the oscillator over the serial port (a one-time exercise > I imagine). And I added a LOCK indicator in one of the removable > plugs right above the reference BNCs on the back panel. Both the > oscillator and the LOCK light are powered from the always on +12V so > there is no warmup when the counter is turned on and the LOCK > indication works when the counter is powered off. And since the fan > runs 24/7 I'm not too worried about the X72 overheating. > > All the extra hardware is mounted on a simple 'L' shaped aluminum > plate that bolts where the Option 010 mounts to the chassis side rail. > I used a 16-pin flat cable that plugs directly into the 53131A main > board. The only modification that was made to the stock counter was > to drill the hole in the plastic plug for the LOCK light. > > Now the Reference Out can also be used to drive other devices as well > (with reasonable accuracy). > > Relatively easy project that can be assembled in a weekend . > > Pictures are attached. > > Skip Withrow > <sRb Mod-1.jpg><sRB Mod-2.jpg>_______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.