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Does anyone have any data on Nuvistors (miniature metal-envelope tubes), or have any to sell? I could use an 8056, and have some 7586s...
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I think this one is 6CW4 , if interested where do I mail it?
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Does anyone have any data on Nuvistors (miniature metal-envelope
tubes), or have any to sell? I could use an 8056, and have some
7586s...
A useful site is Frank's Electron tube Pages, and its mirrors. The 8056 pdf for instance via : . Albert
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Used to have some many years ago.?Will check just in case any are still in the drawer but pretty sure I sold mine to someone on eBay. www.cwgsy.net/private/mandoline "Error 008472. Horrible bug encountered. $Deity knows what happened." On Thursday, 26 April 2018, 09:18:14 BST, Albert Otten <aodiversen@...> wrote: > ? ? Does anyone have any data on Nuvistors (miniature metal-envelope
tubes), or have any to sell?? I could use an 8056, and have some
7586s...
A useful site is Frank's Electron tube Pages, and its mirrors. The 8056 pdf for instance via : . Albert
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Hi Albert,
There are a good few on eBay.co.uk.
Most are in Germany which should be handy for you..
Plenty in the States as well.
Regards
jim
Ei2BB
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On 26 April 2018 at 09:18, Albert Otten <aodiversen@...> wrote:
Does anyone have any data on Nuvistors (miniature metal-envelope
tubes), or have any to sell? I could use an 8056, and have some
7586s...
A useful site is Frank's Electron tube Pages, and
its mirrors.
The 8056 pdf for instance via :
.
Albert
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I might be able to find a couple of 8056 but I am not sure of their condition. Changing them changed the DC offset and i have no way to check them right now. friend of mine has a tube tester but i won't see him for some time because of circumstances. (we aren't on the outs it is other things)
I also have a few of those HV rectifier tubes, and one GZ whatever, 1,400 volt version.
Not much, mainly pay for packing and shipping, $ 20 total each or add more to one package cheaper. (maybe $ 10 ? maybe less) And I WILL pack them correctly. They would have to really try to break them. Let's put it this way - I got carpet padding and wood.
Basically I might get a six pack of decent beer out of it. I have no online or Paypal so either postal MO or personal (yes really) check.
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Greetings,
I may still have some tube data books.
If you will provide the tube numbers of interest I will see if I can supply you some data.
Regards,
Ken
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On 26Apr, 2018, at 3:47 AM, Andre de guerin via Groups.Io <testing_h@...> wrote:
Used to have some many years ago. Will check just in case any are still in the drawer but pretty sure I sold mine to someone on eBay.
"Error 008472. Horrible bug encountered. $Deity knows what happened."
On Thursday, 26 April 2018, 09:18:14 BST, Albert Otten <aodiversen@...> wrote:
Does anyone have any data on Nuvistors (miniature metal-envelope
tubes), or have any to sell? I could use an 8056, and have some
7586s...
A useful site is Frank's Electron tube Pages, and its mirrors.
The 8056 pdf for instance via :
.
Albert
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For some time I have been compiling an index to receiving tube manuals. It is currently complete through 1955, and can be downloaded or read in PDF format from:
A list of the manuals included, with links to copies available online, is at:
Special note - do not use the download link at the bottom of the page, as I have not yet upgraded captcha on my site. Use the first link above.
Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
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Now that I think about it I bet some of these triodes could be replaced with depletion mode N channel FETs. In fact the ones I've seen in the front ends of scopes are common plate so all they do is provide near infinite input impedance, no voltage gain involved. The info I happen to have handy for the 422 has them running with only 20 volts on the plate. I know FETs can handle that.
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At 06:50 PM 4/27/2018, Jeff Urban wrote: Now that I think about it I bet some of these triodes could be replaced with depletion mode N channel FETs. Tek replaced the front-end, sweep generator, and trigger generator Nuvistors (all 8393) with FETs in the 453 beginning with serial 20,000. Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
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Now if they only find something for those tunnel diodes. Actually they don't seem to go bad but I had scopes with tunnel diode triggering and they will just about sync to noise, seriously. I have trouble understanding how the hell they work. I have been inundated with formulae and I/V curves but still it just doesn't register.
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You seem to understand electronics pretty well... You might want
to look up one of the two transistor circuits that behave like a
tunnel diode, build one, and study it. It's probably better to
just consider it magic.
It probably didn't help the tunnel diode's understandability to
name it after the physics property that makes it work. I think
a better name would have been a "trigger diode".
It also doesn't help that the curves that are typically published
are more a manifestation of the curve tracer's very slow speed
capabilities than they are of what the tunnel diode is really doing.
More on that later...
Imagine a part that as you increased the voltage across the part,
the current rises, and rises, and rises, then at a trigger voltage,
the current instantly drops to a near zero lower value... like you
burned out a fuse.
As you let the voltage continue inching its way up, the current stays
low, until it reaches a threshold where it once again starts to rise
endlessly and rapidly, like a conducting diode.
Here's where the typical I/V curves fail you: The current drop at the
tunnel diode's trigger voltage is so fast that you never would be
able to see it on any curve tracer without a ton of intrinsic capacitance
(inside of the curve tracer) slowing it down.
A real curve trace of a tunnel diode would show the trace rising to
the trigger voltage, and then reappearing at the near zero triggered
voltage. It would be discontinuous. There is no there there.
Thanks to magic, the I/V curve is reversible. So, there is really
two trigger voltages: one going up, and one going down.
Through a variety of tricky tricks, you can exploit those sudden
changes in current to produce very pretty trigger pulses. And use
those pretty trigger pulses to trip flip-flops, and multivibrators.
-Chuck Harris
Jeff Urban wrote:
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Now if they only find something for those tunnel diodes. Actually they don't seem to go bad but I had scopes with tunnel diode triggering and they will just about sync to noise, seriously. I have trouble understanding how the hell they work. I have been inundated with formulae and I/V curves but still it just doesn't register.
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Chuck, A real curve trace of a tunnel diode would show the trace rising to
the trigger voltage, and then reappearing at the near zero triggered
voltage. It would be discontinuous. There is no there there.
Didn't you mean to say "trigger current" and "triggered current"? Raymond
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Regarding the tunnel diode branch from this thread - it is indeed possible to see the complete I-V curve of a tunnel diode in low frequency or DC conditions. Normal curve tracers can't do it because their series R is too high, so it appears discontinuous. Specially made, very low resistance test fixtures can suppress the instability caused by the TD's negative R, allowing display of the actual I-V - even that magical negative R region.
You can find such a test circuit in either (or maybe both - I forget) the GE or RCA TD manuals from the 1960s. The circuit displays the I-V on a scope, just like a curve tracer, but it's dedicated to only this function. I had once thought about building one of these, for curiosity, but for general go-no-go testing of TDs, it's not really necessary to see that part anyway. You can trust that the TD is doing its thing if you can see the endpoints, on a regular curve tracer, or in-circuit.
Ed
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I believe the replacement is MPF102, pin for pin. less filament of course.
搁别苍é别
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On 2018-04-27 08:46 PM, Dale H. Cook wrote: At 06:50 PM 4/27/2018, Jeff Urban wrote:
Now that I think about it I bet some of these triodes could be replaced with depletion mode N channel FETs. Tek replaced the front-end, sweep generator, and trigger generator Nuvistors (all 8393) with FETs in the 453 beginning with serial 20,000.
Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
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Replacement of nuvistors with JFET's (specifically, MPF102 JFETs) in the
422 scope vertical amplifiers has been accomplished by "Kurt" and was
documented several years ago in his blog. I believe this is also
described at www.w140.com, under the "422" scope webpage. However, the
plate voltage in the 422 scopes is about +25 volts. The plate voltage
of the nuvistors in the vertical preamps of the 453 scopes (early S/N's)
is about +75 volts, so I suspect this would likely zap a MPF102. There
might be other JFETs that have adequate drain-to-source voltage rating
to serve as replacement for the nuvistors in the 453 (early S/N) scopes.
Mike Dinolfo N4MWP
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On 04/28/2018 05:24 PM, 搁别苍é别 wrote: I believe the replacement is MPF102, pin for pin. less filament of course.
搁别苍é别
On 2018-04-27 08:46 PM, Dale H. Cook wrote:
At 06:50 PM 4/27/2018, Jeff Urban wrote:
Now that I think about it I bet some of these triodes could be
replaced with depletion mode N channel FETs. Tek replaced the front-end, sweep generator, and trigger generator
Nuvistors (all 8393) with FETs in the 453 beginning with serial 20,000.
Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
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Yes, the driver in my description is voltage, and
the current changes with voltage. Sorry for the
confusion.
-Chuck Harris
Raymond Domp Frank wrote:
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Chuck,
A real curve trace of a tunnel diode would show the trace rising to
the trigger voltage, and then reappearing at the near zero triggered
voltage. It would be discontinuous. There is no there there.
Didn't you mean to say "trigger current" and "triggered current"?
Raymond
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At 05:24 PM 4/28/2018, 搁别苍é别 wrote: I believe the replacement is MPF102, pin for pin. less filament of course.
On 2018-04-27 08:46 PM, Dale H. Cook wrote:
Tek replaced the front-end, sweep generator, and trigger generator Nuvistors (all 8393) with FETs in the 453 beginning with serial 20,000.
The Tek parts in the serial 20,000+ 453s were N-channel JFETS, a dual FET, Tek part 151-1011-00 in the front ends, and individual FETs, Tek part 151-1005-00 in the sweep and trigger generators. The former crosses to a dual 2N3822 and the latter to a 2N4303. Both show as "FET Tek Spec" in the manual and were likely selected so the channels would match. Dale H. Cook, GR/HP/Tek Collector, Roanoke/Lynchburg, VA
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Hi Ed,
I know through artifice that you can create plots
of a tunnel diode. A 576 will do it directly, but
it does not match the actual operation of the part,
When the TD gets to the threshold current, it instantly
drops to the lower threshold point. It doesn't wander
lackadaisically down as the curve shows.
The curve shows as it does because it is so totally
swamped by the capacitance of the analyzer that it
smears a trace from the last point where the V/I was
to where it has switched to.
-Chuck Harris
Ed Breya via Groups.Io wrote:
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Regarding the tunnel diode branch from this thread - it is indeed possible to see the complete I-V curve of a tunnel diode in low frequency or DC conditions. Normal curve tracers can't do it because their series R is too high, so it appears discontinuous. Specially made, very low resistance test fixtures can suppress the instability caused by the TD's negative R, allowing display of the actual I-V - even that magical negative R region.
You can find such a test circuit in either (or maybe both - I forget) the GE or RCA TD manuals from the 1960s. The circuit displays the I-V on a scope, just like a curve tracer, but it's dedicated to only this function. I had once thought about building one of these, for curiosity, but for general go-no-go testing of TDs, it's not really necessary to see that part anyway. You can trust that the TD is doing its thing if you can see the endpoints, on a regular curve tracer, or in-circuit.
Ed
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See this 1961 GE TD manual:
The curve tracer circuit begins on page 66.
You need very low resistance and parasitic L and C to get the true LF/DC-version of what's going on. On a regular curve tracer, even with fairly low series R, the blank part is likely where the whole thing is oscillating while it's biased in the negative R zone, so the CT can't see it. With the right resistance levels and conditions, the TD can be biased at any point on its I-V curve - even right in the middle. The circuits described even need different heads specific to the TD current range to get proper viewing - it can be tricky, but it's doable.
Ed
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Jeff Urban
Dale H. Cook
Raymond Domp Frank
Mike Dinolfo