[time-nuts] Re: HP z3816a DC power supply DIP switches

[Dave ZL3FJ]

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:eb at telight.com] 
Sent: Wednesday, March 02, 2022 16:39
To: time-nuts at 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
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