Help identifying a Motorola transistor (in HP 7908 PSU)

[Joe R.]

At 01:26 PM 11/11/05 -0800, Brent wrote:
>David Comley wrote:
>> 
>> I have been trying on and off for a while to map out
>> the schematic for the PSU of an HP7908 disc/tape unit.
>> There's a transistor I can't identify on the board and
>> I am wondering whether anyone can ID this thing for
>> me. The markings show "239" and then the batwings, and
>> then below that it says "4-456". Same problem for a


>> number of the diodes that are labeled "GE010673".

  I would guess that those are GE parts and that that is a GE PN.


>
>Partial help:
>
>"4-456" is probably a short version of the HP house number, 
>the more complete number is likely "1854-0456".

  You're exactly right! IIRC 1854-xxxx are PNP transistors and 1853-xxxx
(same as 3-xxx) are NPN transistors. If you need to cross reference it to a
commercail part try Spere's HP cross reference <http://www.sphere.bc.ca>.


>
>If there's no manual for the 7908 on bitsavers, a (tedious)
>route is find an HP manual for similar equipment (from the 
>same period and which has a chance of using the same part)
>and scan the parts lists for the partial number.
>
>Real-world example: While working on the power supply for an HP 2116,
>I came across a transistor stamped "3-063". The schematic and parts
>lists in the HP manual showed it to correlate to HP house number
>"1853-0063". The parts list then cross-ref'd this to Motorola MJ2268.
>
>If I recall, on the occasions when I've run across this in HP equipment
>from the late-60s/early-70s, the unstated prefix has been "185x".
>I don't know for sure whether it could be another prefix or not.

    Not that I've seen. Nearly every transistor that I've seen in HP stuff
uses this abbreviation. A FEW use the complete PN. I've never seen this
abbreviation on other HP parts but that doesn't mean it's not used.

    Joe
>