Tek 2246 scope, need transistor

Hello: Upon removing the case from my 2246 scope, the case snagged on
the heat sink of one of the transistors in the "VO Gain" section of
the main PC board (not the processor board), breaking the leads of
this transistor. The transistor is a round metallic 3-lead transistor
labelled " Motorola logo, 0846, 8641". It is one of a pair and has a
slip-on metallic heat sink attached. I have been unable to identify
or cross-reference this transistor, and would appreciate any help in
identifying (and hopefully obtaining) another pair of transistors.
Thank you in advance
Todd K4RR

 

All I could find online was the US military PN for that part; 6625-01-275-
4766

The TEK PN is;151-0846-00
8641 is the mfg.date code.(your scope was probably built in 1986-87.)

 

Here is a site advertising TEK spares (including Hard to find). This
may help you further.

http://www.sphere.bc.ca/

Regards,

Ravi.

 

wrote in

I already checked it,no luck.
I suspect IF you could reach a TEK service person,you could get a cross
reference for it.They have all that data on the company intranet.I wish I
could have retained my access to it!

Best chances of success would be the DC field office.

 

I got this hit for Tek semiconductors:

http://www.electromechanicalparts.com/bscA/linecard8/TEKTRONIX.html

Also, I checked a Tek IC reference I had but of course discretes are
absent.

If you cannot locate real spares and if the other transistor of the
pair is good, determine its characteristics (curve tracer, test bench
setups, etc.) and shop for equivalents.

Regards,

Michael

 

-Go to http:\\groups.yahoo.com
-register
-subscribe the "TekScopes" group (copy and paste the name, there's a
group whith a similar name)
-when you can access it a search for Mr. Yanik's ref: 151-0846-00 finds
several threads.

some quotes:

" the Tek cross ref says these are 2N3866A NPN RF power transistors in a
TO-5/39 can, but this part does not work when installed in the scopes,
and the manuals say there is trouble with any transistor that does not
have the base connected to the case."

" These were a custom Tek mod of the standard part.
If you don't use the correct part you will have all sorts of problems
with
frequency response and oscillations as you move your hand or the cover
near
these parts (been there - done that)."


So it looks like you have to find an original...
Best Regards

Steve Sousa

 

Perhaps the broken leads can be repaired on the existing part? How about
finding a TO-92 case transistor with very close specs and build a shield
around it connected to the base?

 

did the part that broke off your scope have it's base connected to the
case? I don't recall that for the 2246.
2N3866A does not ring any bells for that 151-0846 part number,either.

 

-Go to http:\\groups.yahoo.com

I second Steve S's suggestion. The TekScopes group membership are numerous
and very helpful. Members include some Tek retirees. Much helpful info
collected there. I'm sure someone has fixed your particular problem before.

<*> To change settings online go to:
<http://groups.yahoo.com/group/TekScopes/join>
(Yahoo! ID required)

This URL is also the "join" web page.

Good luck,