Mac Plus international analog board with burnt R52

[dangardner]

I've acquired a Mac Plus (international version) which makes a flup flup flup noise. Inspection shows that the analog board around R52 (wirewound 5W 1K) is burnt. I can't find a circuit diagram for the international version which would help me identify any other components (e.g. rectifier) which might also have failed to cause this problem. All the capacitors look perfect. Are there any other components besides R52 which I should replace? Do I need to replace R52 with another resistor in a flameproof ceramic case or are modern resistors flame-resistant enough?

 

[bibilit]

Commonly, the Flup Flup can be issued by a lot of things, but i have found the Optoisalor (CN17 IIRC) being the main culprit.

This is located in the bottom left corner of the board, near the brightness knob.