Hello, I also have a Beocord 9000 device encountering a similar issue with the Rec Cal not stopping. After a preliminary check, I used a multitester with a diode test function. When I applied it to pin 2 of 13P24, the Rec Cal function worked correctly. I'm not proficient in technical matters, and my capabilities only extend this far. I hope fellow enthusiasts can provide assistance. YouTube link of my device:  https ://youtu.be/Zur4gGsA4pY

Yesterday, I had some free time and checked my equipment. I found that 13IC3 was short-circuited. I replaced it with a similar IC, and everything is back in operation. There is still another issue with EQ and sensitivity that I will continue to investigate when I have the time.

Well - I made it so far, that when I disconnetc the  P26 - the 8 pin plug on PCB 11 - the DAC, the autocalibration turns of after been engaged for about 10  seconds - which seems correct. But why - I still dont know I have tried to replace PCB 11 and 13, one at a tim, with PCBs from a working machine - without any changes ;-(

Presumably you know that you can get a readout of the values the calibration has found, so you can check if they have changed or if the results are reasonable? The procedure is outlined in the service manual. With Record Open press Stop and Tape Type at the same time. Display blinks 0000. Press digit 1 to 5 to display the values.