Let's Fix it !!!
If you have GLOBAL bad or very Low Audio in the Reproduce and Sync modes the likely culpret is one of three things... 1) Bad Power... Go Check the Power Supply Voltages at the rear of the machine if bad... you will need to fix it. I HIGHLY suggest hiring a good Tech to fix any Power Supply problems you have !!! 2) Bad BIAS You will need to check the Frequency of the Bias and the Quality of the bias signal... 3) Bad Speed EQ Control Signals Often one or both of the Speed EQ command transistors goes bad and you will lose the EQ Command Signals, meaning the EQ for a speed will be OFF and thus not work.... check to see if the machine works fine in the second speed but not in the first speed.... though it is possible that BOTH speed EQ commands are bad... The Speed EQ Command lines are on the Transport Card. Look in your Manual for the EQ Command Drive Transistors, and check that they turn ON and Off when the speed is changed. If one transistor does NOT switch, change that transistor.