As Ed stated Switchers feeding switchers can be problematic. What I found I had to do was put a relay in series with a slight time delay. This allows the primary switcher to come up and then gets slammed into the secondary SPS. Could be a fet/transistor switch. So linear is preferable. Regards Paul WB8TSL
On Tue, Mar 1, 2022 at 11:20 PM Dave ZL3FJ <2c...@silverbears.nz> wrote: > If its anything like the Z3815A then the supply should provide 24 to 48V DC > at about 25W continuous, and > be capable of providing around 40W for 10 minutes while starting. (this > data is from the unofficial manual for the Z3815A that Murray Greenman, > ZL1BPU, produced some years ago when a number of the Z3815A/GPSR units > appeared on the surplus market down this way) > DaveB, NZ > > -----Original Message----- > From: ed breya [mailto:e...@telight.com] > Sent: Wednesday, March 02, 2022 16:39 > To: time-nuts@lists.febo.com > Subject: [time-nuts] Re: HP z3816a DC power supply DIP switches > > Sam, I noticed in your last post that you're planning to use a printer type > PS. It may work if you luck out, but I suspect that it won't have enough > juice to get things up and running. > > If it's anything like the typical ones I've seen, it's a small SMPS brick, > built for running ink-jet printers. These tend to be just heavy enough for > their normal purpose, but not much beyond. Actually, most SMPSs don't work > well for transient startup conditions like this. In this case, you have to > charge the big filter cap, and take on the negative input R, and the high > initial oven heater load. SMPSs tend to be very quick in protect-response, > and likely will current limit, by going into immediate fold-back, tick > (chirp), or trip (and manual reset) mode. You can of course, try it and see > - it shouldn't hurt anything. If it immediately faults, you can try letting > it do its own soft-start, by connecting the load first, then plugging the > PS > into the line. > > I think your best bet is to use a bench linear PS for experimenting - one > with way more current capability than you apparently need. Then you can > figure out how it all actually works before deciding on the long term > solution. > > Ed > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an > email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send > an email to time-nuts-le...@lists.febo.com > To unsubscribe, go to and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.