I have two questions. The first question is I have an old Hickok Model 533 with a bad bias control. When using it one day the tube tester overheated and burned the bias control. Is the tube tester worth fixing? The second questions is does someone have a copy of the operating instruction for a CA-4 Hickok tube tester adapter. Thanks for any help.

Ross

It's certainly worth repairing, but you'll need to find another bias pot from a junker Hickok (any Hickok model should use a similar pot). There are a lot of Hickoks around with bad or missing meters, so at worst, two 533s could be combined to make one good one.