[Test-Equipment] Need transistor for HP 11710B

[David DiGiacomo]

On Fri, Nov 23, 2012 at 10:58 AM, Bill Abate <wabate at verizon.net> wrote:
> I need a replacement transistor for the A1 converter amplifier board for
> this down converter.  It is Q1 an NPN, to18 case.  It has an in-house number
> and the parts manual only lists it as a silicon, 360 mw.  I substituted a
> 2N2222A and it works but the output is down about 10db.  Anyone know of a
> better sub?

Q1 is listed as an 1854-0019, which crosses to a Motorola SS2188,
which is similar to a 2N2369A.
These are readily available, see eBay or findchips.com
Other gold doped NPNs would probably work too.

>I would try a 2N3646 next.  Then the NPN of the 2N4401 -2N4403 pair would be my next attempt.

Those are too slow.