11 Nov
2005
11 Nov
'05
7:32 p.m.
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".
Thanks - Dave
__________________________________
Yahoo! Mail - PC Magazine Editors' Choice 2005
http://mail.yahoo.com
11 Nov
11 Nov
9:26 p.m.
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".
Partial help:
"4-456" is probably a short version of the HP house number,
the more complete number is likely "1854-0456".
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.
6:05 p.m.
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
12 Nov
12 Nov
1:33 a.m.
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
4-456 is almost certainly an abreviated HP house code. The full version
would be 1854-0456. From that first part of that (1854), it's almost
certainly a silicon NPN device (1853 would be silicon PNP, 1855 an FET,
1850 germanium PNP and 1851 germanium NPN, I think).
Amazingly it's in the equivalents list I have. It crosses to a TIP41A.
Would that make sense?
-tony
2:20 a.m.
Partial help:
"4-456" is probably a short version of the HP house
number,
>the more complete number is likely "1854-0456".
6997
days inactive
6998
days old
4 comments
4 participants
participants (4)
-
ard＠p850ug1.demon.co.uk -
david_comley＠yahoo.com -
hilpert＠cs.ubc.ca -
rigdonj＠cfl.rr.com