Hi Guess 1:
Design it all with the first set of switchers, run it through all the fancy do them one time tests. Get to the last test, fail. Project is now well behind schedule. What's the fast fix? Slap on a wider range / lower emission / better isolation / what ever switcher in front of what you have already. Not pretty, but much faster than doing it right. Guess 2: Inventory items reduction fun and games / use the standard parts list. Much easier to design with parts that somebody else has put into the system than to put in new ones. Might even get a gold star for doing it that way. Companies get on those sort of band wagons from time to time. Bob On Jul 9, 2011, at 11:19 AM, bownes wrote: > My educated guess is that they expected to sell these to telcos, who > traditionally run everything in a central office on -48v and running off of > ac was an afterthought. > > > > On Jul 9, 2011, at 9:43, Marco IK1ODO <[email protected]> wrote: > >> Hello group, >> >> after many years (about 12, I think) of faithful continuous operation, my >> Z3801 failed. >> I opened it, and found that there was no supply to the main PCB. The power >> supply board in the Z3801 (and Z3805, 58503A, possibly all the series) is >> marked 58503-60003. It is a very strange board. It seems to have a first >> DC-DC converter taking 48V input, powering two other DC-DCs that work on 48V >> (!), one supplying +5/+15/-15V to the main board, the other supplying 5V 4A >> to a fourth DC-DC that drives the outer oven with up to 18V. >> Well, it is the first DC-DC that failed. I bypassed it, powering directly >> the no. 2 and 3 from 48V, and all works again. The questions are: does a >> schematic for that board exist? Anyone knows why such a complex power supply >> architecture was adopted? It is not very energy-efficient, all those DC-DC >> run hot. >> >> 73 - Marco IK1ODO / AI4YF >> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
