151-0367-00 and 151-0402-00 transistors


Mark Vincent
 

These are likely to be leaky from C to E as a diode while checking normal
as an NPN. An hfe meter will show way off hfe on the leaky ones. If they
have round leads (tarnished above the socket), they are all leaky. If the
flat face is black with square leads, they likely will be leaky. Check
EVERY one. Some will be leaky and some not even in the same piece. If the
flat face is blue with square leads, it will be fine. The blue flat ones
must be a manufacturing change or different supplier. The 151-0402-00 is in
the 7D15. It may be in other plug-ins. The same checking applies to the
0402. I found that KSP10BU will replace them. Mouser carries these
transistors. The pinout is BEC so be careful when inserting them. The flat
will be turned different than original ones. I had some plug-ins and scopes
that were not quite right in operation after restoring them. These
transistors were the problem. In the Q list of parts, they will have "SEL
FROM 3571TP" under "name and description".

Mark

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