The question is do you really need that coil. Mny coils in scopes are
to tailor the frequency response of the amplifiers, but some are not.
If the coil is bypassed with caps on both sides, likely it is just
there to reduce HF AC currents in the PS busses and/or ground paths.
If so, you can probably just throw a hundrd onhm resistor in it and
forget about it.

Now if it is not bypassed on both ends, it has something to do with
frequency response, and being the horizontal amp you should see some
non-linearity in the sweep at thigher uS/DIV rates. Most likely it
would be a compression at one end or the other, but if it's severe it
could even be a foldover, but that's not all that likely. It really
does depend on the circuit.

Inductors are not generally meant to be fuses, but there are
exceptions. And no matter what, you should determine why it is open.
Did a connection fail, the wire break or whatever ? Or is it burnt to
a crisp ? If it's burnt of course something is shorted. Fix that and
then deal with the coil.

Thinking engineeringwise, 820uH is almost a mH. Pretty big. Now to
tailor the response of an amp stage, they have to deal with high
frequencies. The IE capacitance of the devices is not all tht high
[these days] so at that inductance, it is most likely part of a pi
filter supplying bias to the output stage. If that's true and you just
throw a resistor in ther (after fixing the short) it might not meet
FCC guidlines for RF or EMI. Oh please, whip me to death over that.
This is the most heinous crime of the century. Makes Hitler look like
Ghandi. We must repent.

But if the scope works, we can work another day. Eat, drink, be merry
or whatever.

Wjhat people fail to do is to understand the FUNCTION of the
components they replace. Some are redundant, some oare not critical,
some seem to just be there for looks. At one time I thought with
corporate greed and prifoits above all being the prevailing mindset,
that there would be nothing in a circuit that is no absolutely
essential, but I have learned different. What throws people off is the
don't realize just how cheap it is. That coil could have literaslly
been cheaper than a 47 ohm resistor for all we know.

J