Re: [time-nuts] Schematic for the 'analog' section of an FE-5680A?
Hi Bob, Thanks for that tip. I have tweaked C217 a bit already, but I'll try again in the hope that it'll finally do the trick. By the way, which is the correct direction to push the frequency up a tad -- clockwise or anticlockwise? I think I tried antclockwise the first time... All the best for the festive season. Jim Rowe -Original Message- From: Bob Camp Sent: Saturday, December 14, 2013 5:14 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Schematic for the 'analog' section of an FE-5680A? Hi One thing it could be is the VCXO not quite making it above 10MHz for long enough to lock. I’d tweak the cap to move it up and see what happens. Bob On Dec 13, 2013, at 8:49 AM, ewkeh...@aol.com wrote: Jim unlike older Rb's there is very little analog in the unit. It is sweeping trough its lock range so maybe you may find something around the lamp. The lamp should not be the problem because the 5680 has not been around and been operating for extensive time before pulled. How ever I like to caution time nuts and be careful who they buy from, I did have a bad experience with one vendor and I did post it previously. False claim of new and when returned after return authorization refused refund since I refused to give a 5 star rating. I forwarded the emails to ebay and they did nothing. So any time nut that buys from ggg* fitting deserves what he is getting. We have other sources out there that time nuts have good experiences with and with the price increasing by a factor of 4 one should be careful. Personally I do not think they are worse the price Bert Kehren Miami In a message dated 12/12/2013 4:30:57 P.M. Eastern Standard Time, jimr...@optusnet.com.au writes: Hi, I’m an elderly time-nut newby, and I’ve already struck trouble with a used FE-5680 Rb-vapour reference I bought via eBay. It runs (from +16V and +5V), and the current drain starts at 1.75A and then drops over 5 minutes or so down to about 650mA. But it won’t lock, even if I leave it powered up for a few hours (with a fan to keep it from getting too hot). The output frequency just keeps switching up and down between about 850Hz and 1080Hz, with a bit of ‘lingering’ near each end. And of course the ‘lock’ output at pin 3 stays stubbornly at about 4.35V. To my newby brain, this sounds like the problem is either in the Rb lamp (too dark, perhaps), or else in the photodetector and buffer, etc, forming the ‘dip detector’ part of the feedback loop. Could one of you much-more-experienced time-nutters tell me if my diagnosis sounds right? Also, I’ve found a schematic for the digital sections of the FE-5680A in your archives, kindly drawn up by one of your very experienced members, but has anyone done a similar schematic for the ‘analog’ sections? I suspect I’m going to have to work out for myself where to test for a fault in these sections. There’s also a bit of a mystery (in my mind, at least) regarding that little 2-pin SIL header just near the Rb lamp, on the top of the PCB. Anyone know what that’s for? All the best in anticipation, folks. Jim Rowe ___ 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 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.
Re: [time-nuts] Schematic for the 'analog' section of an FE-5680A?
Hi Bert, Thank you too for your tips and suggestions. I thought there might be 'some' analog circuitry in the 5680A, because the photodetector output from the 'far end' of the Rb resonance cavity probably needs some amplification, before its 'strong enough' to be fed into an A-to-D converter. In any case the schematic I found in the time-nuts archive doesn't seem to include anything in the 'physics package' -- the Rb lamp oscillator, the microwave oscillator feeding the resonance cavity, the photodetector and its output amplifier or whatever. So it looks as if I'm going to have to search around in that area myself... Anyway Bert, thanks again and all the best for the festive season. Jim Rowe Sydney, Australia -Original Message- From: ewkeh...@aol.com Sent: Saturday, December 14, 2013 12:49 AM To: time-nuts@febo.com Subject: Re: [time-nuts] Schematic for the 'analog' section of an FE-5680A? Jim unlike older Rb's there is very little analog in the unit. It is sweeping trough its lock range so maybe you may find something around the lamp. The lamp should not be the problem because the 5680 has not been around and been operating for extensive time before pulled. How ever I like to caution time nuts and be careful who they buy from, I did have a bad experience with one vendor and I did post it previously. False claim of new and when returned after return authorization refused refund since I refused to give a 5 star rating. I forwarded the emails to ebay and they did nothing. So any time nut that buys from ggg* fitting deserves what he is getting. We have other sources out there that time nuts have good experiences with and with the price increasing by a factor of 4 one should be careful. Personally I do not think they are worse the price Bert Kehren Miami In a message dated 12/12/2013 4:30:57 P.M. Eastern Standard Time, jimr...@optusnet.com.au writes: Hi, I’m an elderly time-nut newby, and I’ve already struck trouble with a used FE-5680 Rb-vapour reference I bought via eBay. It runs (from +16V and +5V), and the current drain starts at 1.75A and then drops over 5 minutes or so down to about 650mA. But it won’t lock, even if I leave it powered up for a few hours (with a fan to keep it from getting too hot). The output frequency just keeps switching up and down between about 850Hz and 1080Hz, with a bit of ‘lingering’ near each end. And of course the ‘lock’ output at pin 3 stays stubbornly at about 4.35V. To my newby brain, this sounds like the problem is either in the Rb lamp (too dark, perhaps), or else in the photodetector and buffer, etc, forming the ‘dip detector’ part of the feedback loop. Could one of you much-more-experienced time-nutters tell me if my diagnosis sounds right? Also, I’ve found a schematic for the digital sections of the FE-5680A in your archives, kindly drawn up by one of your very experienced members, but has anyone done a similar schematic for the ‘analog’ sections? I suspect I’m going to have to work out for myself where to test for a fault in these sections. There’s also a bit of a mystery (in my mind, at least) regarding that little 2-pin SIL header just near the Rb lamp, on the top of the PCB. Anyone know what that’s for? All the best in anticipation, folks. Jim Rowe ___ 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 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] Schematic for the 'analog' section of an FE-5680A?
Hi Paul, Thanks for those helpful comments. You have certainly pointed me in the right directions, I suspect. Best wishes for the Festive Season. Jim Rowe -Original Message- From: paul swed Sent: Friday, December 13, 2013 10:10 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Schematic for the 'analog' section of an FE-5680A? Jim I can add some info here. What you suggest is a reasonable conclusion. On some RB modules but I do not believe on the FE-5680s there is a true lamp voltage and its very helpful in determining if the lamps old enough that as you say its dark. On those units if you are below 4 volts approx you know the reference is pretty old. I want to be careful here because someone will say But I have one that works at 2 volts. :-) But that said there are any numbers of failures that will create the issue you could be seeing. There is a modulation signal typically in the 137 hz range and 274 Hz. There is the RF at 6.8 Ghz or so and lastly the rf that excites the RB lamp. Any of these things can be wrong and the system will not achieve lock. If its weak the lamp may glow but essentially run cool in color temperature. But at this point I can say there are indeed really great eperts on here that can give you better guidance. Regards Paul. WB8TSL On Thu, Dec 12, 2013 at 3:05 PM, Jamieson (Jim) Rowe jimr...@optusnet.com.au wrote: Hi, I’m an elderly time-nut newby, and I’ve already struck trouble with a used FE-5680 Rb-vapour reference I bought via eBay. It runs (from +16V and +5V), and the current drain starts at 1.75A and then drops over 5 minutes or so down to about 650mA. But it won’t lock, even if I leave it powered up for a few hours (with a fan to keep it from getting too hot). The output frequency just keeps switching up and down between about 850Hz and 1080Hz, with a bit of ‘lingering’ near each end. And of course the ‘lock’ output at pin 3 stays stubbornly at about 4.35V. To my newby brain, this sounds like the problem is either in the Rb lamp (too dark, perhaps), or else in the photodetector and buffer, etc, forming the ‘dip detector’ part of the feedback loop. Could one of you much-more-experienced time-nutters tell me if my diagnosis sounds right? Also, I’ve found a schematic for the digital sections of the FE-5680A in your archives, kindly drawn up by one of your very experienced members, but has anyone done a similar schematic for the ‘analog’ sections? I suspect I’m going to have to work out for myself where to test for a fault in these sections. There’s also a bit of a mystery (in my mind, at least) regarding that little 2-pin SIL header just near the Rb lamp, on the top of the PCB. Anyone know what that’s for? All the best in anticipation, folks. Jim Rowe ___ 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 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] Schematic for the 'analog' section of an FE-5680A?
Hi If I remember it’s a half turn trimmer. The “right” direction will depend on where they left it … If it’s multi turn then the answer is counterclockwise. Best to simply watch the result on a counter. Bob On Dec 14, 2013, at 4:09 PM, Jamieson (Jim) Rowe jimr...@optusnet.com.au wrote: Hi Bob, Thanks for that tip. I have tweaked C217 a bit already, but I'll try again in the hope that it'll finally do the trick. By the way, which is the correct direction to push the frequency up a tad -- clockwise or anticlockwise? I think I tried antclockwise the first time... All the best for the festive season. Jim Rowe -Original Message- From: Bob Camp Sent: Saturday, December 14, 2013 5:14 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Schematic for the 'analog' section of an FE-5680A? Hi One thing it could be is the VCXO not quite making it above 10MHz for long enough to lock. I’d tweak the cap to move it up and see what happens. Bob On Dec 13, 2013, at 8:49 AM, ewkeh...@aol.com wrote: Jim unlike older Rb's there is very little analog in the unit. It is sweeping trough its lock range so maybe you may find something around the lamp. The lamp should not be the problem because the 5680 has not been around and been operating for extensive time before pulled. How ever I like to caution time nuts and be careful who they buy from, I did have a bad experience with one vendor and I did post it previously. False claim of new and when returned after return authorization refused refund since I refused to give a 5 star rating. I forwarded the emails to ebay and they did nothing. So any time nut that buys from ggg* fitting deserves what he is getting. We have other sources out there that time nuts have good experiences with and with the price increasing by a factor of 4 one should be careful. Personally I do not think they are worse the price Bert Kehren Miami In a message dated 12/12/2013 4:30:57 P.M. Eastern Standard Time, jimr...@optusnet.com.au writes: Hi, I’m an elderly time-nut newby, and I’ve already struck trouble with a used FE-5680 Rb-vapour reference I bought via eBay. It runs (from +16V and +5V), and the current drain starts at 1.75A and then drops over 5 minutes or so down to about 650mA. But it won’t lock, even if I leave it powered up for a few hours (with a fan to keep it from getting too hot). The output frequency just keeps switching up and down between about 850Hz and 1080Hz, with a bit of ‘lingering’ near each end. And of course the ‘lock’ output at pin 3 stays stubbornly at about 4.35V. To my newby brain, this sounds like the problem is either in the Rb lamp (too dark, perhaps), or else in the photodetector and buffer, etc, forming the ‘dip detector’ part of the feedback loop. Could one of you much-more-experienced time-nutters tell me if my diagnosis sounds right? Also, I’ve found a schematic for the digital sections of the FE-5680A in your archives, kindly drawn up by one of your very experienced members, but has anyone done a similar schematic for the ‘analog’ sections? I suspect I’m going to have to work out for myself where to test for a fault in these sections. There’s also a bit of a mystery (in my mind, at least) regarding that little 2-pin SIL header just near the Rb lamp, on the top of the PCB. Anyone know what that’s for? All the best in anticipation, folks. Jim Rowe ___ 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 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 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] Schematic for the 'analog' section of an FE-5680A?
One thing you also should do is set the tuning, even if it sweeps through 10 MHz if outside the lock range it will not lock. I have seen it. Bert Sent from Samsung tabletJamieson (Jim) Rowe jimr...@optusnet.com.au wrote:Hi Bert, Thank you too for your tips and suggestions. I thought there might be 'some' analog circuitry in the 5680A, because the photodetector output from the 'far end' of the Rb resonance cavity probably needs some amplification, before its 'strong enough' to be fed into an A-to-D converter. In any case the schematic I found in the time-nuts archive doesn't seem to include anything in the 'physics package' -- the Rb lamp oscillator, the microwave oscillator feeding the resonance cavity, the photodetector and its output amplifier or whatever. So it looks as if I'm going to have to search around in that area myself... Anyway Bert, thanks again and all the best for the festive season. Jim Rowe Sydney, Australia -Original Message- From: ewkeh...@aol.com Sent: Saturday, December 14, 2013 12:49 AM To: time-nuts@febo.com Subject: Re: [time-nuts] Schematic for the 'analog' section of an FE-5680A? Jim unlike older Rb's there is very little analog in the unit. It is sweeping trough its lock range so maybe you may find something around the lamp. The lamp should not be the problem because the 5680 has not been around and been operating for extensive time before pulled. How ever I like to caution time nuts and be careful who they buy from, I did have a bad experience with one vendor and I did post it previously. False claim of new and when returned after return authorization refused refund since I refused to give a 5 star rating. I forwarded the emails to ebay and they did nothing. So any time nut that buys from ggg* fitting deserves what he is getting. We have other sources out there that time nuts have good experiences with and with the price increasing by a factor of 4 one should be careful. Personally I do not think they are worse the price Bert Kehren Miami In a message dated 12/12/2013 4:30:57 P.M. Eastern Standard Time, jimr...@optusnet.com.au writes: Hi, I’m an elderly time-nut newby, and I’ve already struck trouble with a used FE-5680 Rb-vapour reference I bought via eBay. It runs (from +16V and +5V), and the current drain starts at 1.75A and then drops over 5 minutes or so down to about 650mA. But it won’t lock, even if I leave it powered up for a few hours (with a fan to keep it from getting too hot). The output frequency just keeps switching up and down between about 850Hz and 1080Hz, with a bit of ‘lingering’ near each end. And of course the ‘lock’ output at pin 3 stays stubbornly at about 4.35V. To my newby brain, this sounds like the problem is either in the Rb lamp (too dark, perhaps), or else in the photodetector and buffer, etc, forming the ‘dip detector’ part of the feedback loop. Could one of you much-more-experienced time-nutters tell me if my diagnosis sounds right? Also, I’ve found a schematic for the digital sections of the FE-5680A in your archives, kindly drawn up by one of your very experienced members, but has anyone done a similar schematic for the ‘analog’ sections? I suspect I’m going to have to work out for myself where to test for a fault in these sections. There’s also a bit of a mystery (in my mind, at least) regarding that little 2-pin SIL header just near the Rb lamp, on the top of the PCB. Anyone know what that’s for? All the best in anticipation, folks. Jim Rowe ___ 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 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.
Re: [time-nuts] time-nuts Digest, Vol 113, Issue 34
Hi Corby, My 5065A is s/n 2816A01565 so technically I don't meet the conditions of your query, but I'm still curious what it is that you're looking for! Regards, Stan - Well it's that time again to ask HP 5065A owners if they have early or late SN units. If you have a unit with a SN below 916-00181 or above 2816A01697 please let me know. Merry Christmas and an accurate 1PPS to all! Corby ___ 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] Schematic for the 'analog' section of an FE-5680A?
Jim, I also found my notes for other unit. It sweeps from 9.9997414 to 10.493 and also locks in 3 minutes. Regards, Ignacio EB4APL On 15/12/2013 2:26, EB4APL wrote: Jim, My unit, according to my notes, sweeps between 9.999766 MHz and 10.56 MHz and locks in 3 minutes from cold start. Maybe you have to move the frequency a bit towards the low side. Regards, Ignacio EB4APL On 15/12/2013 0:27, ewkehren wrote: One thing you also should do is set the tuning, even if it sweeps through 10 MHz if outside the lock range it will not lock. I have seen it. Bert Sent from Samsung tabletJamieson (Jim) Rowe jimr...@optusnet.com.au wrote:Hi Bert, Thank you too for your tips and suggestions. I thought there might be 'some' analog circuitry in the 5680A, because the photodetector output from the 'far end' of the Rb resonance cavity probably needs some amplification, before its 'strong enough' to be fed into an A-to-D converter. In any case the schematic I found in the time-nuts archive doesn't seem to include anything in the 'physics package' -- the Rb lamp oscillator, the microwave oscillator feeding the resonance cavity, the photodetector and its output amplifier or whatever. So it looks as if I'm going to have to search around in that area myself... Anyway Bert, thanks again and all the best for the festive season. Jim Rowe Sydney, Australia -Original Message- From: ewkeh...@aol.com Sent: Saturday, December 14, 2013 12:49 AM To: time-nuts@febo.com Subject: Re: [time-nuts] Schematic for the 'analog' section of an FE-5680A? Jim unlike older Rb's there is very little analog in the unit. It is sweeping trough its lock range so maybe you may find something around the lamp. The lamp should not be the problem because the 5680 has not been around and been operating for extensive time before pulled. How ever I like to caution time nuts and be careful who they buy from, I did have a bad experience with one vendor and I did post it previously. False claim of new and when returned after return authorization refused refund since I refused to give a 5 star rating. I forwarded the emails to ebay and they did nothing. So any time nut that buys from ggg* fitting deserves what he is getting. We have other sources out there that time nuts have good experiences with and with the price increasing by a factor of 4 one should be careful. Personally I do not think they are worse the price Bert Kehren Miami In a message dated 12/12/2013 4:30:57 P.M. Eastern Standard Time, jimr...@optusnet.com.au writes: Hi, I’m an elderly time-nut newby, and I’ve already struck trouble with a used FE-5680 Rb-vapour reference I bought via eBay. It runs (from +16V and +5V), and the current drain starts at 1.75A and then drops over 5 minutes or so down to about 650mA. But it won’t lock, even if I leave it powered up for a few hours (with a fan to keep it from getting too hot). The output frequency just keeps switching up and down between about 850Hz and 1080Hz, with a bit of ‘lingering’ near each end. And of course the ‘lock’ output at pin 3 stays stubbornly at about 4.35V. To my newby brain, this sounds like the problem is either in the Rb lamp (too dark, perhaps), or else in the photodetector and buffer, etc, forming the ‘dip detector’ part of the feedback loop. Could one of you much-more-experienced time-nutters tell me if my diagnosis sounds right? Also, I’ve found a schematic for the digital sections of the FE-5680A in your archives, kindly drawn up by one of your very experienced members, but has anyone done a similar schematic for the ‘analog’ sections? I suspect I’m going to have to work out for myself where to test for a fault in these sections. There’s also a bit of a mystery (in my mind, at least) regarding that little 2-pin SIL header just near the Rb lamp, on the top of the PCB. Anyone know what that’s for? All the best in anticipation, folks. Jim Rowe ___ 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] Schematic for the 'analog' section of an FE-5680A?
Jim, My unit, according to my notes, sweeps between 9.999766 MHz and 10.56 MHz and locks in 3 minutes from cold start. Maybe you have to move the frequency a bit towards the low side. Regards, Ignacio EB4APL On 15/12/2013 0:27, ewkehren wrote: One thing you also should do is set the tuning, even if it sweeps through 10 MHz if outside the lock range it will not lock. I have seen it. Bert Sent from Samsung tabletJamieson (Jim) Rowe jimr...@optusnet.com.au wrote:Hi Bert, Thank you too for your tips and suggestions. I thought there might be 'some' analog circuitry in the 5680A, because the photodetector output from the 'far end' of the Rb resonance cavity probably needs some amplification, before its 'strong enough' to be fed into an A-to-D converter. In any case the schematic I found in the time-nuts archive doesn't seem to include anything in the 'physics package' -- the Rb lamp oscillator, the microwave oscillator feeding the resonance cavity, the photodetector and its output amplifier or whatever. So it looks as if I'm going to have to search around in that area myself... Anyway Bert, thanks again and all the best for the festive season. Jim Rowe Sydney, Australia -Original Message- From: ewkeh...@aol.com Sent: Saturday, December 14, 2013 12:49 AM To: time-nuts@febo.com Subject: Re: [time-nuts] Schematic for the 'analog' section of an FE-5680A? Jim unlike older Rb's there is very little analog in the unit. It is sweeping trough its lock range so maybe you may find something around the lamp. The lamp should not be the problem because the 5680 has not been around and been operating for extensive time before pulled. How ever I like to caution time nuts and be careful who they buy from, I did have a bad experience with one vendor and I did post it previously. False claim of new and when returned after return authorization refused refund since I refused to give a 5 star rating. I forwarded the emails to ebay and they did nothing. So any time nut that buys from ggg* fitting deserves what he is getting. We have other sources out there that time nuts have good experiences with and with the price increasing by a factor of 4 one should be careful. Personally I do not think they are worse the price Bert Kehren Miami In a message dated 12/12/2013 4:30:57 P.M. Eastern Standard Time, jimr...@optusnet.com.au writes: Hi, I’m an elderly time-nut newby, and I’ve already struck trouble with a used FE-5680 Rb-vapour reference I bought via eBay. It runs (from +16V and +5V), and the current drain starts at 1.75A and then drops over 5 minutes or so down to about 650mA. But it won’t lock, even if I leave it powered up for a few hours (with a fan to keep it from getting too hot). The output frequency just keeps switching up and down between about 850Hz and 1080Hz, with a bit of ‘lingering’ near each end. And of course the ‘lock’ output at pin 3 stays stubbornly at about 4.35V. To my newby brain, this sounds like the problem is either in the Rb lamp (too dark, perhaps), or else in the photodetector and buffer, etc, forming the ‘dip detector’ part of the feedback loop. Could one of you much-more-experienced time-nutters tell me if my diagnosis sounds right? Also, I’ve found a schematic for the digital sections of the FE-5680A in your archives, kindly drawn up by one of your very experienced members, but has anyone done a similar schematic for the ‘analog’ sections? I suspect I’m going to have to work out for myself where to test for a fault in these sections. There’s also a bit of a mystery (in my mind, at least) regarding that little 2-pin SIL header just near the Rb lamp, on the top of the PCB. Anyone know what that’s for? All the best in anticipation, folks. Jim Rowe ___ 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 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 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.
