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HP-97 on charger only
03-18-2020, 07:30 AM (This post was last modified: 03-18-2020 07:31 AM by teenix.)
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HP-97 on charger only
Hi all,

Has anyone used the HP-97 from the charger only, with no battery connected?

From reading the user manual, it is supposed to be ok, but I was checking over the circuit and it appears that running only from the charger will place about 12V of rectified but unfiltered DC (ie. 100Hz or 120Hz half sine wave) on the supply rails.

The design has an overvoltage circuit which limits the "battery" voltage to a little over the maximum that the switch mode power circuit generates, but not sure what that would be with that sort of input without a battery.

I'm guessing that the card reader probably won't like it, and there won't be enough current to drive the printer.

Just wondering if it actually works at all.

cheers

Tony
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Messages In This Thread
HP-97 on charger only - teenix - 03-18-2020 07:30 AM
RE: HP-97 on charger only - Moggul - 03-18-2020, 08:02 AM
RE: HP-97 on charger only - teenix - 03-18-2020, 11:31 AM
RE: HP-97 on charger only - aurelio - 04-17-2020, 08:01 PM
RE: HP-97 on charger only - Paul Dale - 03-18-2020, 01:24 PM
RE: HP-97 on charger only - teenix - 03-18-2020, 08:14 PM
RE: HP-97 on charger only - isanchez - 04-02-2020, 03:49 PM
RE: HP-97 on charger only - hewlpac - 03-18-2020, 02:23 PM
RE: HP-97 on charger only - AndiGer - 03-20-2020, 05:11 PM
RE: HP-97 on charger only - teenix - 03-20-2020, 09:58 PM
RE: HP-97 on charger only - Hans-Peter - 04-03-2020, 04:39 AM
RE: HP-97 on charger only - teenix - 04-03-2020, 04:53 AM
RE: HP-97 on charger only - aurelio - 04-18-2020, 08:12 PM
RE: HP-97 on charger only - teenix - 04-18-2020, 11:59 PM



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