Hi all,
I'm trying to repair a NAD CD changer - everything works properly except the tray motor is seriously underpowered. It tries to rotate the disc platter but generates a pathetically small force, so that the tray moves very slowly if at all.
I've checked everything mechanically for smooth operation, etc. The motor is a Mabuchi FF-130SH, specs:
The player is trying to drive it in the forwards and backwards directions by applying DC voltages, which measure about 3.9V DC and -3.9 V DC as the player tries to spin it backwards and forwards. In-circuit the motor resistance is about 12.5 ohm, implying it's seeing about 0.3A (right?). So with a listed stall current around 0.5A, does that imply the player is unable to give it enough current to move? Or is the motor resistance too high, preventing the applied voltage from driving enough current? Sorry if these questions are naive.
I've opened up the motor and the brushes look fine - I've cleaned the spindle with Deoxit followed by lubrication with Pro Gold and the motor appears to be spinning freely - it runs smoothly with no load. However when it's reassembled the tray barely moves.
I don't have a service manual for this unit but I am wondering if this is a commonly used motor that people may have experience with - I'm wondering if I should source a replacement motor, or try to figure out why the CD player isn't delivering enough current. As I say, all the other CD player functions appear to work normally, including opening and closing the multi-disc tray.
Any advice would be very welcome - thanks in advance for any help someone may be able to provide.
Thanks,
Matthew.