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

[Sam Bach]

Yeah, I actually figured the current rating of the printer PSU was going to
be an issue, (Rated at 625mA), but shockingly it seemed to not care much
about 1.1 amps being drawn from it.  I was using a linear PSU before but
unfortunately the 25 amp rated one I have only goes up to 16 volts, not
nearly enough, and the one that goes up to 50 volts is only rated at
500mA.  I have another, beefier printer psu of the same voltage but higher
current I'll probably use in the long run, or I'll pick up a cheap 48v PSU
on eBay which should reduce the input current.

Now my experiments have to wait until the antenna adapter and/or
appropriate cable show up because a GPSDO with no antenna isn't very usable!

Thanks,

Sam

On Tue, Mar 1, 2022 at 10:57 PM ed breya <eb at telight.com> wrote:

> 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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