After many years of faithful service, the old 2124 IBM monitor has
gone dark. Turning the power switch off and back on restores the
screen for a few seconds. I have electronic repair skills if someone
knows the problem (seems like it is a capacitor.) Otherwise I am
looking for a larger screen monitor with the old style connection. Is
there one available or do I need a new video card to go with the new
monitor? thanks for any replys.

You don't need a new video card if you replace it
with a CRT monitor.

If you decide to get a TFT screen, you need to
check that it has the old analogue type of
connector. Best to get one that also has a digital
connector too though.

PS. A high quality smaller CRT can look better
than a standard/low quality larger one.