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SKA6516: Difference between revisions
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(Added some curve traces for the 151-0367-00 showcasing the parasitic reverse diode junction.) |
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{{MissingSpecs}} | {{MissingSpecs}} | ||
[[User:Zenwizard|Zenwizard Studios]] found thirteen of these in a [[475]] and thirteen of those tested as having a parasitic reverse diode junction | [[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''. | |||
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''' | ||
The 475 Service manual lists some of the transistors with alternatives, and some without | 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. | 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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151-0367-00 Back.jpg | 151-0367-00 Back.jpg | ||
151-0367-00 Pile.jpg | 151-0367-00 Pile.jpg | ||
151-0367-00_curvetrace.jpg | Typical curve trace of 151-0367-00 in positive direction | 151-0367-00_curvetrace.jpg | Typical curve trace of 151-0367-00 in positive direction ''(Uploader - please add annotation of axes)'' | ||
151-0367-00_curvetrace_fault.jpg | Typical curve trace of 151-0367-00 in negative direction; the transistor has a low reverse bias breakdown voltage | 151-0367-00_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)'' | ||
2N3053_curvetrace.jpg | Typical reverse bias curve trace of a good 2N3053 transistor | 2N3053_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> | </gallery> | ||