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The Tektronix Type 565 is a [[dual-beam scopes|dual-beam scope]] that takes two [[2-series or 3-series vertical plug-ins]].
The Tektronix Type 565 is a [[dual-beam scopes|dual-beam scope]] that takes two [[2-series or 3-series vertical plug-ins]].
Two trigger and sweep modules are contained in the mainframe.  The 565 is similar to the [[556]], but with much
It was [[introduced in 1963]].   
less bandwidth and without tunnel diode triggering.  A rackmount version, the RM565, was also produced.
A rackmount version, the RM565, was also produced.
The triggering signal passes through a [[6DJ8]]-based differential amplifier and then is discriminated by a
Aside from being dual-beam, the 565 is unusual among the
[[6DJ8]]-based Schmitt trigger. As is usual for [[560-series scopes]], the vertical deflection plates of the CRT
other [[560-series scopes]] in the fact that it (the mainframe) has built-in
are driven directly by the vertical plug-in. Aside from being dual-beam, the 565 is unusual among the  
trigger, sweep, and horizontal amplifier circuits.
other 560-series models in the fact that it has built-in trigger, sweep and horizontal amplifier circuits.
 
It is also unusual in that it employs a [[tunnel diodes|tunnel diode]] in the trace intensification circuit.  The tunnel diode
 
== Vertical Signal Path ==
As is usual for [[560-series scopes]], the vertical deflection plates of the CRT
are driven directly, differentially, by pins 17 and 21 of the vertical plug-in.
The left plug-in bay is for the lower beam and the right plug-in bay is for the upper beam.
A 0.7-3pF trimmer capacitor is immediately behind each of the plug-in connectors, and allows
for the mainframe to be calibrated so that plug-ins can be interchanged without requiring the
high-frequency compensation of the system to be readjusted.
The capacitance seen by the plug-in driving the scope should be 14.3pF for the lower beam and the
same for the upper beam. 
 
There is no trigger pickoff in the vertical signal path of the 565.  That function is performed by the plug-ins.
 
 
== Trigger and Sweep ==
The triggering signal comes from pin 11 on the plug-ins, is amplified by a [[12AT7]]-based cathode follower,  
and sent to "TRIGGER" switches.  From there, the trigger signal is sent through a [[6DJ8]]-based differential amplifier  
and then is discriminated by a [[6DJ8]]-based Schmitt trigger.
 
The sweep delay can be adjusted over a range from 10 microseconds to 50 seconds.
 
The 565 is also unusual in that it employs a [[tunnel diodes|tunnel diode]] in the trace intensification circuit.  The tunnel diode
forms as a bistable multivibrator: kick it one way and it turns on and stays on, kick it the other way and
forms as a bistable multivibrator: kick it one way and it turns on and stays on, kick it the other way and
it turns off and stays off.
it turns off and stays off.
== Calibrator ==
The internal calibrator produces 1kHz square waves with amplitude selectable
in decade steps from 1 millivolt to 100 volts.
It is an astable multivibrator formed by one half of a [[12AT7]] and a [[6AU6]].
The other half of the 12AT7 serves as the output cathode follower for the calibrator.
== CRT ==
The 565 uses the [[T5650]] CRT.
== Comparison with [[556]] ==
The 565 appears similar to the [[556]], but is different in many ways.
The 556 uses tunnel diodes for triggering, while the 565 uses tubes.
Also, the 556 uses [[letter-series and 1-series plug-ins]]
while the 565 uses 560-series plug-ins.
Also, the bandwidth of the 556 is specified as 50MHz,
while the bandwidth of the 565 is specified as 10MHz.
Subjectively, the trace of the 565 is very sharp,
sharper than the trace of the 556.


* [http://bama.edebris.com/download/tek/565/565.djvu Tektronix 565 Manual (DjVu)]
* [http://bama.edebris.com/download/tek/565/565.djvu Tektronix 565 Manual (DjVu)]

Revision as of 15:34, 26 May 2014

The Tektronix Type 565 is a dual-beam scope that takes two 2-series or 3-series vertical plug-ins. It was introduced in 1963. A rackmount version, the RM565, was also produced. Aside from being dual-beam, the 565 is unusual among the other 560-series scopes in the fact that it (the mainframe) has built-in trigger, sweep, and horizontal amplifier circuits.


Vertical Signal Path

As is usual for 560-series scopes, the vertical deflection plates of the CRT are driven directly, differentially, by pins 17 and 21 of the vertical plug-in. The left plug-in bay is for the lower beam and the right plug-in bay is for the upper beam. A 0.7-3pF trimmer capacitor is immediately behind each of the plug-in connectors, and allows for the mainframe to be calibrated so that plug-ins can be interchanged without requiring the high-frequency compensation of the system to be readjusted. The capacitance seen by the plug-in driving the scope should be 14.3pF for the lower beam and the same for the upper beam.

There is no trigger pickoff in the vertical signal path of the 565. That function is performed by the plug-ins.


Trigger and Sweep

The triggering signal comes from pin 11 on the plug-ins, is amplified by a 12AT7-based cathode follower, and sent to "TRIGGER" switches. From there, the trigger signal is sent through a 6DJ8-based differential amplifier and then is discriminated by a 6DJ8-based Schmitt trigger.

The sweep delay can be adjusted over a range from 10 microseconds to 50 seconds.

The 565 is also unusual in that it employs a tunnel diode in the trace intensification circuit. The tunnel diode forms as a bistable multivibrator: kick it one way and it turns on and stays on, kick it the other way and it turns off and stays off.


Calibrator

The internal calibrator produces 1kHz square waves with amplitude selectable in decade steps from 1 millivolt to 100 volts. It is an astable multivibrator formed by one half of a 12AT7 and a 6AU6. The other half of the 12AT7 serves as the output cathode follower for the calibrator.


CRT

The 565 uses the T5650 CRT.


Comparison with 556

The 565 appears similar to the 556, but is different in many ways. The 556 uses tunnel diodes for triggering, while the 565 uses tubes. Also, the 556 uses letter-series and 1-series plug-ins while the 565 uses 560-series plug-ins. Also, the bandwidth of the 556 is specified as 50MHz, while the bandwidth of the 565 is specified as 10MHz. Subjectively, the trace of the 565 is very sharp, sharper than the trace of the 556.