Transistor ID...

[Kerry Borgne]

Hi Guys,

Working on an old Zenith battery operated clock radio (60's) The radio I fixed..the clock..not so much. It's a simple thing, just a transistor, center tapped coil and a cap. I need to try the transistor It's marked GE-813 and I can't find it listed anywhere. I THINK it's a germanium PNP but that's a guess...I was hoping maybe someone had some better info on it.

Thanks,

Kerry

[gregebert]

Is this a mechanical clock ? If so, I've seen a similar mechanism before where the coil is briefly energized as the "flywheel" mechanism rotates (it has a small magnet, and I think that induces base-current in the transistor, which causes a larger current to nudge the magnet). Apparently it's enough of a periodic magnetic "jolt" to keep the clock running for several months. In my case, the clock kept stopping because the movement was worn. Yours may have suffered a similar fate. I'm fairly certain the transistor is OK.

I made a bizarre motor by destroying the spring and the escape mechanism. Instead rotating back-and-forth, it simply would spin. I was surprised how fast it could go (several thousand RPM) by cranking-up the voltage. The clock hands did not move because I wrecked the escape mechanism. Eventually, as the voltage was increased the speed got so high that the transistor wouldn't switch correctly, and the motor actually stopped. Lowering the voltage and manually spinning the motor, it ran again. Despite the abuse, the transistor never died.

I suppose you could drill-out the clock face and put nixies in it......or simulate the mechanical hands with neon bulbs like I did with my big clock.

[Kerry Borgne]

P.S. Uploaded my attempt at drawing the circuit. A balance staff/flywheel with magnets swings back and forth under the coil. (Q1 is shown as a PNP, (my guess..)

 

[Instrument Resources of America]

GE at one time, like many others, (NTE comes to mind)  tried to get into the 'general replacement' line of transistors, and that is what I believe this is. I'll see if I can find anything here when I have a little more time. Perhaps tomorrow. I'll bet it's nothing fancy and is most likely a germanium type. Good luck finding those.  If you don't hear from me in a day or so, rattle my cage again. LOL   Ira.

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[Instrument Resources of America]

This sounds somewhat similar to the now very old, and obsolete clocks used in automobiles around sixty years ago. They worked like this. A spring would drive the clock through an escapement. As the spring unwound, two contacts would make, and a small electromagnet would wind the spring back up very rapidly. This would happen roughly every five minutes or so. You could hear it when it happened. Of course no solid state stuff back then, just brute force mechanics. I took one apart once just to satisfy my curiosity. Pretty ingenious for the day. Thanks for the fond memories.   Ira.

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[Instrument Resources of America]

This sounds and looks very much like an "electronic pendulum". Ira.

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[chuck richards]

That GE-813 is an oddball for sure. Absolutely no sign of
it anywhere I've looked so far. That includes Google, my 1962
GE Transistor Manual, and the Radio Shack semiconductor
cross-reference
guide. Nothing even close such as 2N813 nor anything like that.

Yes, in those days there were a LOT of germanium PNPs around!

Chuck

>
>
>---- Original Message ----
>From: deac...@teleweb.net
>To: neoni...@googlegroups.com
>Subject: RE: [neonixie-l] Transistor ID...
>Date: Mon, 27 Apr 2015 16:27:15 -0700 (PDT)
>
>>Hi Guys,
>>
>>Working on an old Zenith battery operated clock radio (60's) The
>radio I
>>fixed..the clock..not so much. It's a simple thing, just a
>transistor,
>>center tapped coil and a cap. I need to try the transistor It's
>marked
>>GE-813 and I can't find it listed anywhere. I THINK it's a germanium
>PNP
>>but that's a guess...I was hoping maybe someone had some better info
>on it.
>>
>>Thanks,
>>
>>Kerry
>>

>>--
>>You received this message because you are subscribed to the Google
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>>To unsubscribe from this group and stop receiving emails from it,
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>>To post to this group, send an email to neoni...@googlegroups.com.

>>To view this discussion on the web, visit

>https://groups.google.com/d/msgid/neonixie-l/ade2ee95-b6d4-4e01-8f5a-
>444a28d444ef%40googlegroups.com.

>>For more options, visit https://groups.google.com/d/optout.
>>

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[Mark Moulding]

This sounds somewhat similar to the now very old, and obsolete clocks used in automobiles around sixty years ago. They worked like this. A spring would drive the clock through an escapement. As the spring unwound, two contacts would make, and a small electromagnet would wind the spring back up very rapidly. This would happen roughly every five minutes or so. You could hear it when it happened. Of course no solid state stuff back then, just brute force mechanics. I took one apart once just to satisfy my curiosity. Pretty ingenious for the day. Thanks for the fond memories.   Ira.

Actually, they were even more clever than that.  To reduce the manufacturing precision needed, the tension of the escapement spring (which in concert with the mass of the pendulum wheel determines the "tick" frequency) was adjustable.  Furthermore, the adjustment would occur, by a small fixed amount, every time the clock was set.  So, if the clock was running slowly, and you reset the time ahead, the spring would be set a little tighter too, so that the clock would then run slightly faster.  After a few days of setting the time, it would be perfectly, so to speak, "dialed in".  The ultimate accuracy, while never great, could definitely get to be around a minute per week or so.

The only time this screwed up was for daylight savings time adjustments, and even this would correct itself within a day or two of resetting the clock.

(I took one apart too, from the 1970 Cadillac I had in college.  At first I didn't understand why some of the linkages seemed so sloppy, then I discovered that this was part of the auto-adjustment mechanism.)
~~

[chuck richards]

I once had a clock which I found when someone was throwing it away.
It ran on a set of (2) "D" cells in series. It was a springwound
clock, it would run for about ten minutes per winding. When spring
tension got low, a little motor would kick in and wind it back up.
A set of batteries would last just over a year.

Finally it died because the motor eventually failed and also
the contacts to start the motor got flaky.

But it did put in a couple years of good service after I found it.

It was not a real precise timekeeper either maybe a minute or two
per week or so.

Chuck
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[Charles MacDonald]

Getting back to the original enquiry, my guess is that the
characteristics are not too critical.

sounds from the original description that the transistor is being used
as an on -off switch, and the voltage is known, the current it must pass
can be measured. The soviets made Germanium Transistors for long
periods after they faded in the west, so they do turn up from the same
band of sellers who sell soviet Nixie tubes. (there: list content)

My guess is that a germanium transistor may not even be really needed,
perhaps a trial of a 2N3906 from the parts bin will do?

or am I dreaming in technicolour as usual?

--
Charles MacDonald Stittsville Ontario
cm...@zeusprune.ca Just Beyond the Fringe
http://Charles.MacDonald.org/tubes
No Microsoft Products were used in sending this e-mail.

[Instrument Resources of America]

Sooooooo,,,,,,,,,,,,,,what's wrong with dreaming in technicolor. As soon
as I finish lunch, I'm going to try and find some info on the G.E.-813
transistor. Ira

[John Rehwinkel]

> Working on an old Zenith battery operated clock radio (60's) The radio I fixed..the clock..not so much. It's a simple thing, just a transistor, center tapped coil and a cap. I need to try the transistor It's marked GE-813 and I can't find it listed anywhere. I THINK it's a germanium PNP but that's a guess...I was hoping maybe someone had some better info on it.

What kind of package is it in? Also, is there any chance the "8" is really a "B"? Some of the early GE transistors had strange part numbers like 4JD1B3.

- John

[David Forbes]

I will see if it's in the old GE transistor book I have, when I get home.

[Instrument Resources of America]

I just finished lunch and my research has not yielded too much so far.
I've looked through several GE semiconductor catalogs,,,,,,nothing.
Loose leaf literature in file cabinets full of such stuff,,,,,nothing.
Finally I turned to Newark, Allied, Lafayette, Mouser parts catalogs,
and in the Newark catalog ""dated 1968"" on page 136 in the upper right
corner of the page I found what is evidently the beginning of these G.E.
"general replacement semiconductors". Here is what it says, "Universal
replacement transistors. Highly dependable, replacement low cost
transistors, which are designed as general replacements for most types
of transistors used in radio and hi-fi sets." They started with GE-1 and
end with GE-11 in the table right below that. That is exactly what I
stated earlier, about the GE-XXX numbered items being 'general
replacements for home electronics'. With this in mind I can tell you
that someone has been into this clock radio and done a repair 'before
you'. I worked as a kid in high school as a tech in a repair shop that
handled warranty repairs for Sony, and Sony did NOT originally use GE
general replacement semis, in any of their products, they were ALWAYS
Sony semi's. I also went out in our parts room and found several boxes
full of these GE replacement transistors. The one's I have start at GE-2
and go through GE-316. I also did find a reference to a GE-509 in a
later GE cross reference book. It is therefore entirely possible and
probable that they eventually hit GE-813 and even higher. I don't think
it will be to difficult for you to find something suitable that will
work o.k. If I find more I'll let you know. I just went and grabed my
1998 edition of my 'NTE general replacement catalog'. On page 2-55 it
lists the GE semi's, starting with GE-1 and ending with GE-74196,
HOWEVER, NO GE-813. Any chance you may have misread the part number?
Good luck, Ira.

[Kerry Borgne]

Hi Guys, thanks for the suggestions! The idea of it having been worked on before never entered my mind.. it should have! Now of course that creates and added issue of, was the right transistor used.. (NPN,PNP..) I guess I do could both. Seems to me that back then, with germanium transistors, internal leakage was often depended on for bias. (or something like that, it's been a while!) The quest goes on.
 Also I included the pictures since there was some discussion about how it works. I think a modern equivalent would be one of the 'click/clack' animated toys that run on a solar cell. In the pictures you can see the balance wheel with the magnets mounted on it that swings back and forth under the coil that I THINK serves as the trigger coil and also the pulse coil that gives the wheel its kick. 

[gregebert]

Whoa! That looks a lot like the clock mechanism I was talking about, though it's been 35 years since I messed with it. I recall it ran on a single C-size battery. Also, to start the clock you had to pull-and-release the knob used to set the time. It gave the escapement a small kick. Unfortunately I couldn't find it in my junkbox, so I must have tossed it away years ago.

[Kerry Borgne]

There was also some discussion about the old car radios that used a coil to 'autowind' the clock every few minuets. The escapement would advance a cam and eventually allow a set of points to make contact, energizing a solenoid which would rewind the drive spring and open the points. Worked pretty good, drew a significant amount of current and after time the contacts would pit and the operation became unreliable...

 I found the clock above which works on a similar principle. The escapement moves a cam that eventually allows a set of points to make contact which activates the motor. That motor drives the digital number display, rewinds the drive spring asm and resets the cam. Oddly the cam/motor/contact portion works good.. the escapement drive sucks. It can run fast, or slow depending on who knows what...

[GastonP]

Do you happen to have a photo of the top of the transistor? Those old TO-5 packages many times have the standard denomination in the top and left the sides for fabrication date, lot, etc.

Also, from what I have seen, GE used black in some of their early silicon switching transistors. I have several 2N697 that are just like that.