Looking for Data on transistor OC940

Do you have a question? Post it now! No Registration Necessary

Translate This Thread From English to

Threaded View



Hello  Hobbyists and Enthusiasts,

I am looking for data on an old transistor
type OC940.   I think it is made by Philips.

I had a search around the web with no luck,
perhaps some of you may have some old
transistor Data books from the 60's and 70s.

I know it is a high voltage transistor but I was
just wondering if there was anything special
about it having low inter-electrode capcitance
or anything like that.  This OC940  is Q9 in
an old BWD 502 oscilloscope.  

The mention of the giveaway BWD 502 upthread
has re-kindled my interest to try and get it working
properly for my friend since he has thrown some
time and money at it.   I spoke to McVan instruments
but no luck there.  

 While speaking to a very helpful chap at McVan,
I mentioned a missing switch on the trigger pot that
 is different from the schematic I have and the unit.
He explained the pot was dismantled by BWD,
a drop of arldite was then placed at the end of the
pot track to lift the wiper and act as a switch.
How is that for tricky!   Heh heh heh....
I would never had known!

There is no urgency here, just nice to get an old
CRO working a bit better than it is at present.
Thanking you in advance.

Regards,
John Crighton
Hornsby


Re: Looking for Data on transistor OC940


There's a blast, from the past

try searching for "germanium transistors oc"



Quoted text here. Click to load it



Re: Looking for Data on transistor OC940



Quoted text here. Click to load it

Hello Tony,
no luck on that tack either.
Regards,
John Crighton
Hornsby

Re: Looking for Data on transistor OC940


On Fri, 15 Jul 2005 01:12:48 GMT, john snipped-for-privacy@tpg.com.au (John Crighton)
wrote:

Quoted text here. Click to load it

Are you sure it is OC940? Could it be OC440? My old Philips short form
catalog lists OC140 and Mullard lists a OC440.

OC440 is, I believe, a pnp high speed switch and according to Mullard
is equiv to OC203 which they say has Vce60%V. Unfortunately, I have no
other info.
Quoted text here. Click to load it


Re: Looking for Data on transistor OC940


On Fri, 15 Jul 2005 04:06:10 GMT, Ross Herbert

Quoted text here. Click to load it


Hello Ross,
according to the manual that I have for this old BWD 502 scope,
transistor Q9 is an OC940    but on the same line in the manual DC940
is used.  OC940 is used on the schematic. To add more confusion the
chap at McVan  said it was a silicon type.   Just like  Tony Maher,
 I assumed Germanium.

The ring in transistor that is fitted to the Q9 spot is a silicon. The
original is long gone. The scope is 35 years old.  If this Q9
transistor should be a germanium type  and a silicon type  is
fitted then that would not be good.  Just for fun I will try
fitting a germanium type.

I am following this repair up out of interest only.  I will ask the
chap who is giving away a BWD 502  in the other thread
"Free CRO to good home"
what the type number of transistor Q9 is. Maybe he has
a few minutes to take the covers off and take a look.

Thanks for looking up your data books Ross, much
appreciated.

Regards,
John Crighton
Hornsby



Re: Looking for Data on transistor OC940



"John Crighton"

Quoted text here. Click to load it



**  Lots of later OC type numbers were  silicon  !!!

  Check OC200, 201, 202 and 203  for examples.

 All low voltage silicon PNPs from Philips /Mullard.




..........   Phil





Re: Looking for Data on transistor OC940


On Fri, 15 Jul 2005 19:59:26 +1000, "Phil Allison"

Quoted text here. Click to load it

Hello Phil,
yes,  I have just been reading about the origins
of the European type number system.
O for zero heater volts and C for transistor and
then how every transistor would start with  OC.
Changes had then to be made.
Interesting reading......I look for something
and spend lots of time reading  other stuff.
Takes me ages to find a word in the dictionary
because I check out so many other words first. Heh heh heh
Regards,
John Crighton
Hornsby






Re: Looking for Data on transistor OC940


On Fri, 15 Jul 2005 10:28:23 GMT, john snipped-for-privacy@tpg.com.au (John Crighton)
wrote:

Quoted text here. Click to load it
From memory "C" means a three element device (triode in valve
terminology) "A" = diode  "B" = double diode (I think). So germanium
or silicon diodes were OAxx, transistors OCxx.

The correlation in valves were things like ECC83 which was "E" = 6.3v
heater "CC" - double triode, etc.

Hope my memory is not failing too much!

Alan

--
++++++++++++++++++++++++++++++++++++++++++
Jenal Communications
We've slightly trimmed the long signature. Click to see the full one.
Re: Looking for Data on transistor OC940


Quoted text here. Click to load it

the first transistors I ever used were AC128's.

Cheers
Terry

Re: Looking for Data on transistor OC940



"Terry Given"

Quoted text here. Click to load it

**  I can beat that.

I used my first OC71 as a phototransistor by scraping the black paint off
the case !

After a long stint with valves like the 6V6, 5Y3, 6AC7, 6BE6, 12AU7 and
12AX7   -   I moved onto 8 watt audio amplifiers employing the  AD161 / 162
output pair with AC127 and AC 128 as drivers.

Geraniums did  "wilt"  rather easily so in the very late  60s, when silicon
types like the BDY20 & 2N3055 appeared, along with the 40409 / 40410  &
TT800 / TT801 driver pairs,  I reckoned we were finally onto something.




........   Phil



Re: Looking for Data on transistor OC940


On Sat, 16 Jul 2005 17:16:41 +1000, "Phil Allison"

Quoted text here. Click to load it

How close does a BC558 or PN2222 come to that??


Re: Looking for Data on transistor OC940



"The Real Andy"
Quoted text here. Click to load it


**  The TO-18 (small metal) series of silicon  NPN transistors BC107, 8, 9
were released here in the late 1960s  -  with gold plated leads.  Then came
the similar  PNP  series of  BC 177, 8 , 9.

Then the SOT-25, angular plastic versions  BC147, 148, 149  etc appeared a
year or so later.

Then there were the  TO-106  "dome top"  versions BC 207, 8, 9  etc.

Then finally the TO-92 versions,  BC 547, 8, 9   &    BC 557, 8 , 9.

The PN....  series appeared in the mid 1970s,  IIRC -  as plastic versions
of some previous 2N....  prefix devices.


It was a regular silicon device invasion in the late 60s and early 70s !!!



...........   Phil



Re: Looking for Data on transistor OC940



Quoted text here. Click to load it

Yep, I remember the "good 'ol" days (or was it the bad old days) too.
Used an OC71 as a single stage audio amplifier for a crystal set when in
late primary school. :( Gee seems like an eternity ago!

The following year in high school I built a regenerative detector AM radio
that used an OC45 in the RF stage followed by an OC71 audio amplifier.  A
chance to recycle some of the components.  And yes they were expensive back
in those days when you had to finance your electronics projects from pocket
money :(

After that came the AC125 (close enough T01 equivalent to the OC71) and the
AC126 (less c-e leakage and a slightly higher operating frequency
capability) and of course the AC127 / AC 128 used in simple complimentary
symmetry output stages (with flag heatsinks bolted to a strip of aluminium
for a whole whopping 300mW output at 10% THD.

I also had a handful of GET104 transistors made by G.E.C.  They were PNP Ge
types.  Got no idea how old they were.  Also some Telefunken AF117 (circa
1960).

Things have sure come a long way since then.

Cheers,
Alan



 



Re: Looking for Data on transistor OC940


Ahhh the good old days.  My first was a single transistor radio I built
using an OC44 - later I added an OC74 (Ithink it was) to give a bit more
volume

David

Terry Given wrote:

Quoted text here. Click to load it


Re: Looking for Data on transistor OC940


Howdy,

According to the schematics for the BWD502, Q9 reads as BC940.



On Fri, 15 Jul 2005 09:42:11 +0000, John Crighton wrote:

Quoted text here. Click to load it


Re: Looking for Data on transistor OC940



Quoted text here. Click to load it


Hello MWP,
I may be getting somewhere now. I have model 502  s/n 5669
My schematic is for s/n 7129 and above.  (the wrong one)   dwg 620A

Is your schematic dwg number 620 for serial numbers below 7129 ?
If so, may I have a copy or scan?  Your out of pocket expenses
will be gladly fixed up.

Regards,
John Crighton
18 Talwong Street
Hornsby Heights
NSW 2077





Quoted text here. Click to load it


Re: Looking for Data on transistor OC940


Serial number is 16572.
Drawing number is 1194.
I'll copy it and post it up.


On Mon, 18 Jul 2005 04:02:54 +0000, John Crighton wrote:

Quoted text here. Click to load it


Re: Looking for Data on transistor OC940



Quoted text here. Click to load it

Hi,
the serial number is much higher but I am
still interested to see the schematic.
Thanks for that.

When Michael, the new owner starts repairs
we might be able to compare waveform and
voltage readings to help each other.
Regards,
John Crighton,
Hornsby


Re: Looking for Data on transistor OC940



"John Crighton"


Quoted text here. Click to load it


 **  I bet the BF336, 337 or 338 would be suitable equivalents  -  all in
TO39 ( TO5 ) packs.

These are rated at 185, 250 and 300 volts,  with  an 80 to 160 MHz Ft.

WES sell the latter two for a $1.45 and $1.25 each.

BWD used the BF 336 in several models,  like the 539B.




..........   Phil





Re: Looking for Data on transistor OC940


On Fri, 15 Jul 2005 18:36:24 +1000, "Phil Allison"

Quoted text here. Click to load it



Hello Phil,
thanks for that information.  Impressive specs and cheap,
I'll pick up a few.  I have a 539D.  Still works fine.

I was just mentioning to Ross that I am not sure
if the OC940  or (DC940) is silicon or germanium.

Phil, remember  some time ago you sent me a file of
a schematic for a BWD820.  Well, today I picked
up another old BWD820 for my friend who owns
this poor performing BWD502.    This 820 has
dirty pots and intermitant switches. Definitely
a goer with a bit of carefull cleaning, which my
friend is capable of doing.  So he now has an
upgrade from a 10 Mhz scope to a 25Mhz scope.
The University of technogy Sydney (UTS)  are
disposing of their old scopes of various models,  
but I picked the faulty 820 because I had a
schematic for it, courtesy of you.
I thought you might like to know that bit of trivia  :-)

A reader of this group put me on to the scopes
for sale at the UTS.   (Thanks  "A" )

Regards,
John Crighton
Hornsby


Site Timeline