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Tag: Tektronix 556 Fan Repair


Tektronix 556 Fan Motor Repair Part 2

Posted by Shaun Merrigan in Electronics, Oscilloscopes, Tektronix 556. Comments Off on Tektronix 556 Fan Motor Repair Part 2

22nd January

Tektronix 556 Fan Motor Repair Part 2

In this continuation of Tektronix 556 Fan Motor Repair Part 1, I have removed the motor and mount assembly and disassembled it.  Now I need to figure out the problem and rebuild the motor.

Tektronix 556 Fan Motor Overview, mounted in place

Tektronix 556 Fan Motor removed from mounts.  The Tektronix part number is 147-0029-00.

 

Tektronix 556 Fan Motor removed from mounts.

Tektronix 556 Fan Motor removed from mounts.

The next few images show the disassembled parts of the motor:

Rotor, end bells and bushing assembly

End bell inside, retainer, spring washer felt and bushing.

End bell and bushing assembly

Rotor and spacers

At this point I found several issues by visual inspection:

The original rear bushing had been replaced, probably due to excessive internal wear.
The replacement itself had excessive internal wear and it did not fit in the retainer properly due to its shape.
The replacement … Read More »


Tektronix 556 Fan Motor Repair Part 1

Posted by Shaun Merrigan in Electronics, Oscilloscopes, Tektronix 556, Vacuum Tubes. Comments Off on Tektronix 556 Fan Motor Repair Part 1

19th January

Tektronix 556 Fan Motor Repair Part 1

I was recently fortunate enough to acquire a Tektronix 556 Dual Beam Oscilloscope with many accessories and in good condition.  Unfortunately, the cooling fan on the scope was very loud and more concerning, it emitted an alarming metal on metal contact sound.  After verifying basic operation of the oscilloscope, I decided to repair the cooling fan.  This process is documented in the images and commentary that follow.

Part 1: Removing the Noisy Fan Motor

556 Cooling Module with filter and mesh screen removed.  The fan is connected to the chassis wiring at the ceramic terminal which is circled:

Fan to chassis wiring connection terminal.

 

Inside of cooling module and bottom side of motor (fan blade removed):

Back side of motor (fan blade removed).  This is a 4 pole 1725 rpm (loaded) motor.  It moves a very large volume of air.

An … Read More »