KLH Model 21 found at Goodwill today!

[zeno]

On IC's it may not have used them. They went disco in the
80's IIRC. The way the IF is built I would NOT go
there unless needed.

If the main filter is not the hum check the outputs next
& any transistors direct coupled to them. They will probably get HOT fast.
Its probably the transistors mounted on the chassis in round
holders.

73 Zeno