Hi,
Someone correct me if I am wrong, but
just about any power adapter
with same power and Voltage rating and plug tip polarity and size will do as a power adapter replacement for the original Chronos power adapter.
From my side I had success using an adapter from a Laptop from a very common Brand.
of course, before using it,
look at the specs written down on the adapter, and even best :
have it measured with a probe.
you should first verify the tip polarity, then the voltage, then the amp rating. and of course that the tip Do Fit the female plug.
there are Plug tip adapters for a few bucks if the adapter you want to use as a backup has a slight different tip size.
Dont fear to use a 5 Amps rated adapter when Chronos original is rated 3 (this is an example, I am lazy and dont remember the exact rating, and dont want the hassle right now to give exact rating

)
I mean for Amps rating, higher is better, and the Chronos will draw only what it needs.
But if your power adapter is lower Amp rated than the Chronos adapter, then it might be not powerful enough and you may probably face issues.
what is mostly IMPORTANT is to respect the Voltage range rated on the Chronos adapter, around 22 Volts if i remember well,
with some margins.
over voltage you will probably fry everything and make your Chronos a very nice paperweight.
same for the plug tip polarity, although most devices, nowadays can detect and protect against reversed polarity
well get yourself a probe, (multimeter) and measure the raw voltage, and see if plug inner tip is positive or negative,
this is drawn as a pictogram on the power adapter generally but cost nothing to verify it yourself.
then compare (if you can) with the original Chronos Power adapter.
If within same range and specs, it should work.
it worked for me, I have verified everything, plug it and .. yeah ! it works !