SKA6516: Difference between revisions

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(Forgot to add axes annotations. I also appear to have been incorrect in a multitude of stances. I apologize.)
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[[User:Zenwizard|Zenwizard Studios]] found thirteen of these in a [[475]] and showed that thirteen of those tested as "having a parasitic reverse diode junction" on a cheap component tester.
[[User:Zenwizard|Zenwizard Studios]] found thirteen of these in a [[475]] and showed that thirteen of those tested as "having a parasitic reverse diode junction" on a cheap component tester.
''There is no such diode, parasitic or not'' – the cheap tester displays this symbol when the DUT has a low reverse breakdown voltage as seen in the traces below.
:''There is no such diode, parasitic or not'' – the cheap tester displays this symbol when the DUT has a low reverse breakdown voltage as seen in the traces below. See the thread at https://groups.io/g/TekScopes/topic/101335545#201002.
See the thread at https://groups.io/g/TekScopes/topic/101335545#201002''.
: Since reverse breakdown can damage the DUT, small-signal RF transistors should not be tested on component testers that may trigger that breakdown.  They should be checked only on a curve tracer.
 
Since reverse breakdown can damage the DUT, small-signal RF transistors should not be tested on component testers that may trigger that breakdown.  They should be checked only on a curve tracer.


'''Suitable Modern Replacement'''
'''Suitable Modern Replacement'''

Revision as of 03:03, 4 April 2024

The SKA6516  (P/N 151-0367-00) is an NPN Transistor. Note: possibly incomplete info, service manuals to be checked.

Key Specifications

  • please add

Zenwizard Studios found thirteen of these in a 475 and showed that thirteen of those tested as "having a parasitic reverse diode junction" on a cheap component tester.

There is no such diode, parasitic or not – the cheap tester displays this symbol when the DUT has a low reverse breakdown voltage as seen in the traces below. See the thread at https://groups.io/g/TekScopes/topic/101335545#201002.
Since reverse breakdown can damage the DUT, small-signal RF transistors should not be tested on component testers that may trigger that breakdown. They should be checked only on a curve tracer.

Suitable Modern Replacement

The 475 Service manual lists some of the transistors with alternatives, and some without, i.e. some may need to be closer in spec than others. A list of eighteen has been extracted from the Service Manual and is shared on the 475 Repairs page.

In his video, Mr ZenWizard Studios used Fairchild/On Semi KSP10BU from Mouser. Farnell has them, too.

In the 1982 Common Design Parts catalog, -0367 is Cross referenced as AST3571 which appears to be a custom 2N3571.

Pinout

The pinout of this transistor does not correlate with most modern BJTs. With the flat part facing you, from left to right, the pin is collector, base, and emitter. Incorrectly inserting a modern replacement thinking that it follows a standard emitter base collector can potentially bring down the equipment.

Pictures

Used in

Some instruments using part SKA6516

Instrument Manufacturer Class Model Description Introduced
465 Tektronix Oscilloscope 465 Portable 100 MHz dual-trace scope 1972
465B Tektronix Oscilloscope 465B Portable 100 MHz dual-trace scope 1980
466 Tektronix Oscilloscope 466 Portable 100 MHz dual-trace storage scope 1974
475 Tektronix Oscilloscope 475 Portable 200 MHz dual-trace scope 1972