Re: Tektronix 2230
I was busy expanding the GridTied Solar panels we have here, hence again my later response.
In terms of temperature, my personal feeling is: The lower, the better.
In my 2215A('s) I have seen temperatures around 60 - 63 Celsius, a temperature I feel comfortable with.
But on the other hand, you have a 2230, so more electronics to power, so maybe higher temperatures in that scope...
In terms of electrical isolation you must keep using the Mica or more modern isolator, but I would add a TO-220 heatsink at both sides of the metal frame where the FET is mounted.
A bit like in this picture: https://groups.io/g/TekScopes/photo/64919/4?p=Name,,2215+repair,20,1,0,0
The addition of the two TO-220 heatsinks will improve lowering the FET's temperature, also with the FAN mounted in place.
Also, do put that little screw in the side panel back in when you close up the scope, that also helps cooling that part of the power supply.
This brings me to the Molex connector you still see in that picture: I never liked them.
They are very susceptible to corrosion, so it is easy to develop an extra serial resistance which will affect the operating settings of the FET, and might even rise the temperature.
So, in addition of what you see in the picture mentioned above, I would solder the wires directly to the FET after mounting it to the metal frame.
Have a nice weekend,