547

The 547 is a 50MHz scope that takes letter-series and 1-series plug-ins. It has two identical timebases and , when used with the 1A1, 1A2, or 1A4, has the ability to display one input with one time scale and another input with a different time scale. The effect is similar to a dual-beam scope assuming that the input signals are repetitive. This "Sweep Switching" feature differentiates the 547 from the 546.

Triggering is done with tunnel diodes. The 'A' trigger is based on a 10mA tunnel diode. Up to serial number 11889, it uses a TD253. From 11890 onward, it uses a 152-0140-01.

The 547 uses the Tektronix 154-0478-00 CRT.

A common problem with 547s is the HV transformer. Rather than potting the HV transformer in wax, as was done up to that point, the 547's HV transformer was potted in epoxy. Unfortunately, this epoxy turned out to absorb moisture over time, particularly when used in humid climates. The moisture causes increases losses in the transformer. Excessive losses requires the regulator to drive the 6AU5 input oscillator tube (V800) harder. Eventually, the drive circuit can not supply enough power to keep the supply in regulation. The usual solution is to scavenge a replacement transformer from another scope. As a labor of love, hobbyists have been known to rebuild the HV transformers. This is discussed from time to time on the Yahoo TekScopes forum.

The 547 has a five-stage BJT vertical amplifier that is fully differential from the plug-in connector to the CRT vertical deflection plates. There is one tube in the vertical signal path, a 12AT7 acting as a unity-gain buffer between the plug-in connector and the vertical amplifier.

There is a 170 nanosecond delay line between the first and second gain stages.

• Tektronix 547 Manual (DjVu)
• Tektronix 547 Manual (PDF)

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  Front view

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  Vertical amplifier

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  Trigger A