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.
