Restoring a HP9830B calculator.

[Tony Duell]

(05-26-2014 08:16 PM)MattisLind Wrote:  I tried the REWIND button. But there were nothing but a spinning sound. No motion. I think that there should be a clicking sound from the solenoids. Either there is some fault or they were just stuck.

Yes, the rewind solenoid should operate. This is controlled by a little bit of circuitry on the Motor Control PCB and shouldn't be hard to sort out. Start by checking the solenoid itself, you are going to have problems if it is open-circuit.

Look at page 84 of 'my' schematic .pdf. The solenoid drive transistor is fed from the same signal that enables the motor. So it could be a defective transistor. Or a bad connection. But not much else.

(05-26-2014 08:16 PM)MattisLind Wrote:  When I looked into the tape unit I found that the rubber on the wheels were quite worn, so I need to fix that.

The repair articles you have mention this. The 'tyre' is a standard O-ring, you can take the drive apart, remove the 'beam' with the motors on it, and replace the O-rings.