Dear Time Nuts, This post was time ago.... but at this moment I'm working on my FE-5680. I had to replace a 74HCT74 IC inside the unit to get the 1 PPS out. Now I'm wondering what the other pins are used for. As far as I have figured out now the following pins are used:
1 +15V 2 gnd 3 lock low = unlock high 4 n.c. (this unit has an internal +5 V logic to drive the 2^23 divider chain; this generates the 1 pps from the 8,.... MHz) 5 gnd 6 1 pps out 7 ? 8 ? 9 ? Inside I find a small PCB directly behind the DB-9 connector. I guess this is a smart C-field adjustment. It has three wires going to the motherboard. +5 V, Gnd and an analog voltage. I guess this voltage is slowly varied over the lifetime of the unit by using an internal counter/clock, to adjust the C-field. Just curious about the knowledge which is accumulated in the Time-Nuts community about these units... Best regards, Jeroen Rex wrote: >On Sun, 18 Sep 2005 15:52:03 -0500, James Meek <[EMAIL PROTECTED]> >wrote: > > > >>I've just found the time-nuts mail list, and the threads >>concerning the programming of the FEI FE-5680A rubidium >>frequency sources that some have bought on ebay and been >>unable to program. >> >>I, too, bought one of these from an internet source last year >>(a different source from the one mentioned in the thread I found), >>and was unable to get anything out of it by simply powering it >>up and connecting to it through its 10-pin interface using the >>pinouts for a standard FE-5680A. >> >>However, mine did not come naked or on a cut-off section of PC board >>like those I've seen advertised on ebay since then. Rather, it >>came attached to a large board containing several voltage regulators, >>a serial interface buffer, a serial EPROM chip, and some other logic. >>Although I have not yet found the time to fully analyze the >>circuitry, it appears to have been set up so as to program the >>FE-5680A from the serial EPROM. I have no idea whether it needs >>to receive a command from an external source to initiate that >>programming, or whether it happens at power-on (perhaps with the >>clocking of the serial EPROM by the FE-5680A itself?). >> >>I read that Rex and Brian Kirby have figured out that the unit needs >>a +5V supply (or perhaps just a logic input) in addition to >>the 15V supply in order to get any output. If someone could >>provide me with specifics on that and anything else they've discovered >>about this part, I'd have a lot more incentive to try to figure >>out what the EPROM does -- and of course would share my findings >>with all here. >> >>JM >> >> > >Here's what I worked out for the pins on the DB-9 on my5680A... > >1 +15V near 2A initially, dropping to about .8A warm >2 gnd >3 lock high = unlock >4 +5V about 160 mA >5 gnd >6 1 pps out >7 10 MHz out >8 RS-232 Rx (into rubidium) >9 RS-232 Tx (from rubidium) > >The initial impression from the seller was that only 15V was needed. The >info on the FEI pages don't mention needing 5V in any option. A lot of >the pin functions are different from any description I have seen. > >I think I have the same full board you have. I looked at it back around >the beginning of the year. If I remember right, the RS-232 pins of the >rubidium get fed from off-board signals. I did power it up using this >board once. There is a dual color led at the edge of the board that >indicates lock state, if I remember right. > >Does your board have a sticker on it somewhere that says: SGLA4000B High >Stability Osc Assembly? After lots if web searching, I figured that >this seems to be part of older Motorola Cell equipment. I found a site >that says they repair them. I tried sending an email asking if they have >any documentation, but got no reply. > >Maybe later I can find time to scan the board. What I remember from the >hacking I did, was that there didn't seem to be anything intelligent >going on on the board. I don't remember any details though, maybe I >missed something. > >Oh, on the side of the rubidium there is an adjustment screw. I thought >for sure this would adjust the C-field and hence the freq, but I don't >see any result by turning this. No idea what it is for. > >I tried all sorts of things sent to the serial port but never saw any >effect or reply. I tried this at various baud rates. I also scoped the >other side of the MAX3232 chip inside, so I know the data was getting in >there. The other port of the MAX3232 is connected too. It goes to what >must be a maintenance header inside. Nothing interesting came from >trying that port too. > >So, if you feed it both 5V and 15V, I'd bet your unit will come up and >give you 1 pps and 10 MHz. If, like mine, the frequency is a little bit >off, it sure would be nice to know how to adjust it. > >-Rex, KK6MK > > >_______________________________________________ >time-nuts mailing list >time-nuts@febo.com >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > > -- Ing. Jeroen Bastemeijer Delft University of Technology Department of Electrical Engineering Electronic Instrumentation Laboratory Mekelweg 4, Room 13.090 2628 CD Delft The Netherlands Phone: +31.15.27.86542 Fax: +31.15.27.85755 E-mail: [EMAIL PROTECTED] GPS: Lat N52.00002 Lon E4.37157 Alt 46.2m _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts