SKA6516: Difference between revisions

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 {{MissingSpecs}}
-[[User:Zenwizard|Zenwizard Studios]] found thirteen of these in a [[475]] and thirteen of those tested as having a parasitic reverse diode junction; a curve trace of the 151-0367-00 exhibiting a low reverse breakdown voltage can be seen in the images.
+[[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.
+See the thread at https://groups.io/g/TekScopes/topic/101335545#201002''.
-A list of eighteen has been extracted from the [[Media:Tektronix_475_Oscilloscope_Service_Manual.pdf|Service Manual]] and is shared on the [[475/Repairs#Problematic Transistors|475 Repairs]] page.
+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 - so I'd be careful to check that some need to be closer in spec than others.
+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 [[Media:Tektronix_475_Oscilloscope_Service_Manual.pdf|Service Manual]] and is shared on the [[475/Repairs#Problematic Transistors|475 Repairs]] page.
 In his [https://www.youtube.com/watch?v=gEXYRPNohyA video], Mr [[User:Zenwizard|ZenWizard Studios]] used [[Media:KSP10.pdf |Fairchild/On Semi KSP10BU]] from [https://eu.mouser.com/ProductDetail/onsemi-Fairchild/KSP10BU Mouser]. [https://uk.farnell.com/c/semiconductors-discretes/transistors/bipolar-transistors?st=ksp10&showResults=true Farnell] has them, too.
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 -0367-00 Back.jpg
 -0367-00 Pile.jpg
--0367-00_curvetrace.jpg | Typical curve trace of 151-0367-00 in positive direction
+-0367-00_curvetrace.jpg       | Typical curve trace of 151-0367-00 in positive direction ''(Uploader - please add annotation of axes)''
--0367-00_curvetrace_fault.jpg | Typical curve trace of 151-0367-00 in negative direction; the transistor has a low reverse bias breakdown voltage
+-0367-00_curvetrace_fault.jpg | Typical curve trace of 151-0367-00 in negative direction; the transistor has a low reverse bias breakdown voltage ''(Uploader - please add annotation of axes)''
-N3053_curvetrace.jpg | Typical reverse bias curve trace of a good 2N3053 transistor
+N3053_curvetrace.jpg            | Typical reverse bias curve trace of a good 2N3053 transistor (note this is a low-frequency power device with large junctions so it is not comparable to the 151-0367-00)
 </gallery>