Re: UPS workaround?

On 6/14/26 12:39, Robert Heller wrote:
> At Sun, 14 Jun 2026 10:13:32 -0400 Eben King <[email protected]> wrote:
> 
>>
>> On 6/14/26 10:07, John Hasler wrote:
>>> Before you replace it open it up and reseat and retighten all the
>>> connections (especially the battery terminals).
>>
>> Did that. I disconnected them all, checked the battery voltages (13.4
>> and something else reasonable), and checked the 60A fuse between them.
>> It's a weird fault, that it goes instantly from completely normal to bad.
> 
> Does it still work as a "dumb" UPS?

You know, I haven't checked that.  I would just need to unplug the USB 
and reboot the UPS, correct?

> If so, one possible temp solution is to
> get an "old" dialup modem.

I actually do have two external modems, one 14.4 and one 33.6.  I'm 
fairly sure that at least one of them works.  Just gotta find them...

> Plug the modem's power brick into the *mains*, and
> connect the modem's TTY connection to a RS232 <=USB adapter and then you can
> get powerd and have it monitor the ModemReady signal.

Wait, I'm not clear on the connections.

UPS -> modem through RS-232
then what does powerd do?

  The modem will assert
> ModemReady so long as it has power. ModemReady will drop when there is a power
> failure. (I suspect that this is probably not really a viable option.

Yeah.  If it just tells me when there's a power failure, the beeping 
would tell me.  Unless you're saying that powerd could kick off processes?

> These days are probably rare and PCs no longer have RS232 ports...)

I might have to use a USB -> RS232 adapter.  The previous UPS had only 
regular serial and I used one of those, and when the boot procedure 
initted the USB ports it sent something down the serial cable (BREAK?) 
which caused the UPS to power off. Not ideal.