Does anyone have a service manual for the Sony SQR-4750 or know the part number or values for the 4 level pots they use. I'm guessing they may be the same level pots used on other SQR receivers. Maybe if I'm lucky they used them on other things too. Or if you are parting out an SQR receiver and have a level pot that would be even better. I need other service done on it finally and it would be nice to fix the broken level pot when I do. Thanks.