Trying to bring back a AA501


So I am finally working up the nerve to put an AA501 on the bench and run it through its checks. From a preliminary check in It looks like the voltage section is working well and tracking with my meter that is freshly in cal. However, it seems the distortion side needs some help. I have not tried to do a calibration on it yet as I have been a little nervous to open it up. With a shorting bar on the inputs it says 0.0079% distortion. With the outputs floating it is about 0.0303% with a signal applied from a wein bridge at about 1Khz 6.5V Pk I get a distortion figure of 100.3% distortion. On a scope that oscillator is a clean sign wave. On volts a 6.5V Pk voltage reads 4.65 VRMS. Math says it should be 4.63 so that could be with in the margin of error. A fluke 8840A reads 6.54~ off the peak detector of the oscillator. Any gotcha’s I should know about a AA501 before I start running through the service manual. I have had to repair the front connector it was very loose to the case. But that has been repaired.

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