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

[Sam Bach]

Hi, thanks for the info.  I'll definitely check out the RS-422 thing, I was
suspicious that might be the case.  I think I'll probably try the thing on
24V and see if it's willing to start.  The power adapter I plan to use for
it is one from a printer that puts out 31V, so it would probably work fine
set for 24 or 48, I guess.  I'll probably pop the PCB off and have a look
at it, I'm curious to see what those switches control as well.

Thanks!

Sam

On Tue, Mar 1, 2022 at 4:41 PM Hal Murray <halmurray at sonic.net> wrote:

>
> spbach1234 at gmail.com said:
> > Here are some pictures of the PSU and power connector area, if anyone
> has any
> > insight into what voltage this thing is expecting.  What's confusing to
> me is
> > that the original marking, 20-72 V was crossed out, 48V written over the
> top,
> > and then the DIPs internally being set to 24A.  I'm not really sure what
> the
> > A and B positions mean, either.
>
> I haven't worked with the Z816A.
>
> It was common for gear of that era to work with either 24 or 48V.  The
> input
> range was typically 2:1.  Thus 48 meant anywhere from 36V to 72V and 24
> meant
> 18 to 36.
>
> I have no idea what the A in 24A means or what the manual would say about
> the
> switches.  The label has a 24B so maybe there are 2 input connectors.  If
> it
> was on my bench, I would take it apart and look at the bottom of the power
> supply board and/or try to trace out the switches.  That's not a high
> power
> switch so maybe it selects some switching mosfets.  But I don't see any.
> So
> maybe the switch is good for the amp or 2 and maybe they run 2 in parallel.
>
> If it's designed for 24 or 48, it might not explode if run with 48 when
> setup
> for 24 so I wouldn't be too surprised if the label didn't match the
> switches.
> Maybe somebody tried it on 48 and it worked.
>
>
> > Is the female DE9 on this wired so I can just plug a USB-Serial adapter
> into
> > it directly, like a Trimble Thunderbolt, or do I need to make a
> null-modem
> > cable?
>
> The Z3811/12, KS-24361 L101/2 units that were available a few years ago
> send
> RS-422 (5V differential pairs) on a 9 pin connector.
>
> I'd put a meter or scope on some of the pins.  If you see 5V, the pinout
> for
> the KS-24361 should be in the archives.  Mine worked with the right set of
> direct connectios to a typical PC serial port.
>
>
>
> --
> These are my opinions.  I hate spam.
>
>
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