Re: [time-nuts] Internal 5 volt switching regulator on some non-programmable FE-5680A's
On Sun, Jan 8, 2012 at 3:01 PM, David davidwh...@gmail.com wrote: If noise was so important I wonder why they did not use a lower noise switching regulator or the LT1375 which supports oscillator synchronization. Maybe noise WAS important, so they removed the regulator altogether. That would fixed the noise problem 100% and save $3 in parts. The other reason to remove the regulator is just to save the $3. Chris Albertson Redondo Beach, California ___ 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.
Re: [time-nuts] Internal 5 volt switching regulator on some non-programmable FE-5680A's
I suspect the reason was far simpler: 5 volts was available in the system, why not use it and take the small amount of heat out of the box. There would also be a reliability improvement, one less regulator per freq standard. I bet the cost of the regulator is insignificant compared to the unit itself. On 01/09/12, Chris Albertsonalbertson.ch...@gmail.com wrote: On Sun, Jan 8, 2012 at 3:01 PM, David davidwh...@gmail.com wrote: If noise was so important I wonder why they did not use a lower noise switching regulator or the LT1375 which supports oscillator synchronization. Maybe noise WAS important, so they removed the regulator altogether. That would fixed the noise problem 100% and save $3 in parts. The other reason to remove the regulator is just to save the $3. Chris Albertson Redondo Beach, California ___ 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.
[time-nuts] Internal 5 volt switching regulator on some non-programmable FE-5680A's
Hello, After posting a few days ago about one of my '5680A's having the voltage converter installed - but not connected - I've done a bit of reverse-engineering and sleuthing around and (probably) have a fairly complete picture of what it would take to populate that section of the board. That information may be found here: http://ka7oei.com/10_MHz_Rubidium_FE-5680A.html This page is a work in progress, using my LPRO-101 page as a template and unashamedly stealing a good chunk of its content - most of which is directly applicable, anyway! Note that I haven't done the board population myself and there *may* be additional jumpers that need to be added/removed - or, as I suggest, one could avoid that problem and simply connect to known V+ and +5 volt points instead. If you happen to have one of those boards with the installed (but not connected) regulator, information is also included on which two jumpers I needed to add to enable it: Again, YMMV, DNTHFB, etc... If anyone populates their own board, please let me know how it worked out. I add this mostly out of interest expressed by a few others that emailed me. It's no doubt far easier/cheaper to simply add an outboard 7805 (or switching converter) than populate the board, but hey, why not? 73, Clint KA7OEI ___ 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.
Re: [time-nuts] Internal 5 volt switching regulator on some non-programmable FE-5680A's
On Sun, Jan 8, 2012 at 1:51 PM, Clint Turner tur...@ussc.com wrote: Hello, After posting a few days ago about one of my '5680A's having the voltage converter installed - but not connected - I've done a bit of reverse-engineering and sleuthing around and (probably) have a fairly complete picture of what it would take to populate that section of the board. That information may be found here: http://ka7oei.com/10_MHz_**Rubidium_FE-5680A.htmlhttp://ka7oei.com/10_MHz_Rubidium_FE-5680A.html This page is a work in progress, using my LPRO-101 page as a template and unashamedly stealing a good chunk of its content - most of which is directly applicable, anyway! Are you sure about those resistor values? They look like 5.11K and 5.62K (standard 1% values) to me. Orin, KJ7HQ. ___ 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.
Re: [time-nuts] Internal 5 volt switching regulator on some non-programmable FE-5680A's
On Sun, 8 Jan 2012 14:23:02 -0800, Orin Eman orin.e...@gmail.com wrote: On Sun, Jan 8, 2012 at 1:51 PM, Clint Turner tur...@ussc.com wrote: Hello, After posting a few days ago about one of my '5680A's having the voltage converter installed - but not connected - I've done a bit of reverse-engineering and sleuthing around and (probably) have a fairly complete picture of what it would take to populate that section of the board. That information may be found here: http://ka7oei.com/10_MHz_**Rubidium_FE-5680A.htmlhttp://ka7oei.com/10_MHz_Rubidium_FE-5680A.html This page is a work in progress, using my LPRO-101 page as a template and unashamedly stealing a good chunk of its content - most of which is directly applicable, anyway! Are you sure about those resistor values? They look like 5.11K and 5.62K (standard 1% values) to me. I agree. Besides not requiring rare and expensive 4 significant digit precision resistors which just happen to match the marking of the standard 1% resistors, the nonstandard 12.95K and 11.15K on the schematic would yield 5.23 volts. 5.62K and 5.11K will yield 5.08 volts from the nominal 2.42 volt reference on the LT1376. The 5 volt resistor selection in the data sheet would have been closer but maybe they wanted the extra 7 millivolts or were compensating for the feedback bias pin current. If noise was so important I wonder why they did not use a lower noise switching regulator or the LT1375 which supports oscillator synchronization. ___ 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.
Re: [time-nuts] Internal 5 volt switching regulator on some non-programmable FE-5680A's
Hi, Are you sure about those resistor values? They look like 5.11K and 5.62K (standard 1% values) to me. Whoops - you are right: In squinting at the board I'd thought about turning the thing 180 degrees since the numbers look believable either way! These two 5k-ish values are more in line with the values called out in the data sheet for the '1376 (4.99k/5.36k). I look forward to hearing from someone who might take on populating these components on the board and what they find. 73, Clint KA7OEI ___ 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.
