Date   

Re: 7603 CRT max possible bandwidth?

 

Hi guys,
thanks for the amazing replies, that's some great food for thought.
I'm especially thrilled to find out about the 519/519C.
I'm very happy to have found out about the French company Thomson-CSF
and the American EG&G. Something to look out for in the future.

Cheers,
D.

On Sat, Jul 13, 2013 at 6:14 AM, David <davidwhess@gmail.com> wrote:
On Fri, 12 Jul 2013 14:35:37 -0500, David <davidwhess@gmail.com>
wrote:

On Fri, 12 Jul 2013 20:21:10 +0200, "cheater00 ."
<cheater00@gmail.com> wrote:

David,

On Fri, Jul 12, 2013 at 3:03 PM, David <davidwhess@gmail.com> wrote:
The horizontal bandwidth is usually limited by the horizontal CRT
amplifier which is designed for linearity at the expense of bandwidth.

CRT bandwidth is ultimately limited by the deflection plate design.
CRTs faster than the 760x have distributed vertical deflection plates
to support bandwidths above 100 MHz. The 7104 CRT has distributed
horizontal deflection plates to support a 250 MHz horizontal bandwidth
with a horizontal CRT amplifier that looks more like the vertical CRT
amplifier in a slower oscilloscope.

So the 760x CRT should support at least 100 MHz in either direction
and the difference in horizontal and vertical bandwidth is mostly
because of the CRT amplifiers. You could always test it by turning
the CRT 90 degrees and hooking it up.

The 760x CRT bandwidth ultimately depends on the lumped nature of the
deflection plates. You could drive them with a lower impedance
amplifier up to the point where the series inductance becomes a
limiting factor.
Interesting. How far up do you think this will go in terms of vertical
deflection? 200MHz? 400 MHz? What's the fastest oscilloscope with this
type of deflection plate arrangement?
If you study the Tektronix Circuit Concept documents on vertical
amplifiers and CRTs, you can find two different limits on CRT
bandwidth:

1. The lumped deflection plate load on the vertical CRT amplifier will
limit deflection frequency response. The 200 MHz Tektronix CRTs use
impedance matching and CRT terminations to help with this but with
care, I think you could compensate for this in the vertical amplifier.
That would get the 7603 CRT up to at least 200 MHz.

2. The transit time of the electrons past the deflection plates
creates a sin(x)/x type of frequency response. Tektronix CRTs faster
than 200 MHz use distributed deflection plates to get around this
limitation by having the deflection voltage wave pace the electrons.
If this was a problem, then I think you could alter the cathode
voltage to change the electron velocity past the deflection plates and
trade off deflection sensitivity for bandwidth but then the deflection
amplifier would need to produce a higher output voltage to get the
same deflection.


------------------------------------

Yahoo! Groups Links



Re: 7603 CRT max possible bandwidth?

 

Hi Dennis,

On Sat, Jul 13, 2013 at 6:57 AM, Dennis Tillman <dennis@ridesoft.com> wrote:
They designed two vertical amplifier plugins for it. The M2000 was a 3GHz, 50 ohm plugin and the M3000 was similar except it had a variable delay feature. The output of both plugins was single ended and coupled to the mainframe using a SMB connector.
I have one of each of the vertical plugins.
What you have is M1000 and M2000. The M1000 doesn't have the rear
connector BNC, only the M2000. How's the remainder of the red paint on
that one holding up?

The module was not Gaussian. It had terrible overshoot and ringing.
What does "Gaussian" mean precisely in this context? I don't know
where to look for a definition. Sounds like something I should know.

Cheers,
D.


Re: Help with Tektronix 2445.

tgyuri59
 

If anyone is interested in, I have repaired and calibrated this oscilloscope.

--- In TekScopes@yahoogroups.com, "tgyuri59" <timar_gyorgy@...> wrote:

Greetings,

I have successfully repaired three Tektronix oscilloscopes.
These were 2467B, 2440 and a 2445B.
Thanks for the help what I got here in this.
The 2467B has a bad Trigger hybrid.
The 2440 has a bad CCD Driver Process hybrid, and a broken attenuator.
The 2445B has a defect A5 panel, with leaking caps, and some bad SMD resistors on it.
All of three scopes got new PS caps.
These are working well now.
But there is a 2465.
This was caught me.
(It was not difficult because my English is not so good, and my knowledge of electronics is negligible.)
So, this turned out not 2465, but 2445 within inside.
It is could be working despite of this of course.
I have changed PS caps, elcos on A1 and digital control board.
It has a correct readout display.
The POST run without error.
All of the control knobs working.
I have replaced all of the hybrids, with a known good ones
(except U800).
I planted it U975, because this was missing.
I have changed U160, U170, U165, U980 and Q155.
Nothing happened.
But what is the problem here?
There is no trace.
Trigger LED almost always lit.
If I playing hardly with Trigger HoldOff and Trigger Level knobs,
there shows correct signals all of the four channels, for some moments.
If I setting the Time Base to 5 ns/DIV there is a stable trace.
I'm trying to check the test waveforms.
It is strange to me, #20-#21 waveforms doesn't show up correctly at U950 pin 10.
It has very-very jittery edges.
All of the 2,4ms period signals not stable.
But I don't know, what makes these signals?
Is the digital control bad possibly?
I hope you are understand me.
Any help appreciated.

Best Regards,

Gyuri


Re: 7603 CRT max possible bandwidth?

 

Hi Don,

 

They didn’t know what the Navy was going to use it for. They told me it was a Navy contract and they were not told what they were used for (or wouldn’t say). I suspect that when the Navy got the instruments they were not impressed with the performance. I also suspect this was a Pork Barrel contract from their local congressman

 

The remarkable thing is that these two engineers were able to build something that had the appearance of being plausible. From an engineering standpoint it was a sort of doppelganger. It caused a few people at Tek to sit up and take notice. Eventually, from even 3000 miles away, Tek realized it was not practical to do. If the folks at Tek had actually seen how B&H gutted several of the 7104 subsystems that are fundamental to all analog scopes they would have laughed at it.

 

To their credit I have to say that for Bernie and Harvey to even think it might be possible to do something like this took either bold imagination or chutzpah.

 

Dennis

 

From: Don Black, Sent: Friday, July 12, 2013 10:22 PM

Thanks Dennis, the 7109 was a typo, meant 7104 (that sounds better than senior moment ;) ). I was aware of the examples of higher bandwidth special amplifiers using the 7104 and the trade off of frequency at the expense of bad transient response. However it's good to see your more detailed description. I thought some of the foreign GHz scopes might have been direct view but you may be right about them all being coupled to readout tubes. I guess the old 519C was direst view without any MCP.
It would be interesting to know what they used the modified 3GHz 7104 system for. If it was impulse work the poor transient response would seem significant (I wonder if they could analyze the results and allow for the pulse distortion)? If it was just frequency response then something like a sampling scope or spectrum analyzer would seem better. Perhaps they just did it to prove they could (higher, faster, stronger).

Don Black.


On 13-Jul-13 2:57 PM, Dennis Tillman wrote:

Hi Don,

There was no 7109. But you may be thinking of something B&H Engineering (Bernie and Harvey Horowitz, Monroe, NY) made. They modified a Tek 7104 to take advantage of the exquisite 1 V/Div vertical deflection sensitivity of the 3GHz CRT. The did this by removing the entire vertical interface, differential delay line, and vertical amplifier and replacing it with a single ended connection using a proprietary 3GHz amplifier module they developed.

They designed two vertical amplifier plugins for it. The M2000 was a 3GHz, 50 ohm plugin and the M3000 was similar except it had a variable delay feature. The output of both plugins was single ended and coupled to the mainframe using a SMB connector. The heart of these two plugins is a single module made from discrete parts for amplification, the 3002, which they designed and sold. The module was not Gaussian. It had terrible overshoot and ringing.

They don’t remember if they made 2 or 3 complete systems for the Navy. I have one of each of the vertical plugins. I met with them last month to learn the fate of the mainframes in hopes I could get one donated to the VintageTEK museum but they were given to the Navy for whom they were developed and lost track of them.

From the exterior, the 7104 they modified looks exactly like a conventional 7104. If you open one up it would become immediately obvious that the vertical amplifier was removed and replaced with a 2” x 2” module which directly drove the vertical deflection plates.

There is no way to verify their claim that this scope was capable of 3GHz. The technology to do that didn’t exist in a form that a small company of their size could afford at that time. Even Tek was unable to confirm the performance of the CRT beyond 3GHz.

Dennis

From: Don Black, Sent: Friday, July 12, 2013 8:00 PM

I don't think that's what I had in mind. I believe there was mention of it several years ago here when there was discussion of the 7109, third party amplifiers and pushing it's bandwidth to 3 GHz. It might have been discussion around the old 519 without amplifiers, just talking about the tube frequency limit. Does anyone else remember it or are the pixies playing with my mind?

Don Black.


Re: 7603 CRT max possible bandwidth?

Don Black <donald_black@...>
 

Thanks Dennis, the 7109 was a typo, meant 7104 (that sounds better than senior moment ;) ). I was aware of the examples of higher bandwidth special amplifiers using the 7104 and the trade off of frequency at the expense of bad transient response. However it's good to see your more detailed description. I thought some of the foreign GHz scopes might have been direct view but you may be right about them all being coupled to readout tubes. I guess the old 519C was direst view without any MCP.
It would be interesting to know what they used the modified 3GHz 7104 system for. If it was impulse work the poor transient response would seem significant (I wonder if they could analyze the results and allow for the pulse distortion)? If it was just frequency response then something like a sampling scope or spectrum analyzer would seem better. Perhaps they just did it to prove they could (higher, faster, stronger).

Don Black.

On 13-Jul-13 2:57 PM, Dennis Tillman wrote:
 

Hi Don,

 

There was no 7109. But you may be thinking of something B&H Engineering (Bernie and Harvey Horowitz, Monroe, NY) made. They modified a Tek 7104 to take advantage of the exquisite 1 V/Div vertical deflection sensitivity of the 3GHz CRT. The did this by removing the entire vertical interface, differential delay line, and vertical amplifier and replacing it with a single ended connection using a proprietary 3GHz amplifier module they developed.

 

They designed two vertical amplifier plugins for it. The M2000 was a 3GHz, 50 ohm plugin and the M3000 was similar except it had a variable delay feature. The output of both plugins was single ended and coupled to the mainframe using a SMB connector. The heart of these two plugins is a single module made from discrete parts for amplification, the 3002, which they designed and sold. The module was not Gaussian. It had terrible overshoot and ringing.

 

They don’t remember if they made 2 or 3 complete systems for the Navy. I have one of each of the vertical plugins. I met with them last month to learn the fate of the mainframes in hopes I could get one donated to the VintageTEK museum but they were given to the Navy for whom they were developed and lost track of them.

 

From the exterior, the 7104 they modified looks exactly like a conventional 7104. If you open one up it would become immediately obvious that the vertical amplifier was removed and replaced with a 2” x 2” module which directly drove the vertical deflection plates.

 

There is no way to verify their claim that this scope was capable of 3GHz. The technology to do that didn’t exist in a form that a small company of their size could afford at that time. Even Tek was unable to confirm the performance of the CRT beyond 3GHz.

 

Dennis

 

From: Don Black, Sent: Friday, July 12, 2013 8:00 PM

I don't think that's what I had in mind. I believe there was mention of it several years ago here when there was discussion of the 7109, third party amplifiers and pushing it's bandwidth to 3 GHz. It might have been discussion around the old 519 without amplifiers, just talking about the tube frequency limit. Does anyone else remember it or are the pixies playing with my mind?

Don Black.



Re: 7603 CRT max possible bandwidth?

Don Black <donald_black@...>
 

Thanks Cliff, that's probably the equipment I was thinking of, quite remarkable performance for its time. Keeping to the Tektronix theme, the time line shows the 519C as a 3 GHz scope but with only 180 vols / cm sensitivity. I can't recall anything about this version, perhaps a few hand made specials for the nuclear laboratories? Does anyone know any details (manual, hen's teeth??).
It's interesting how most of the scopes current in 1983 used MCPs  and mention was made of one failure due to the MCP after 9000 hrs. In light of discussion about the 7104 MCP fragility that sounds like a long life.

Don Black.

Don Black

On 13-Jul-13 1:28 PM, Cliff White wrote:
 

Here's what I think you're remembering: http://w140.com/kurt/campbell83/

Image 5 talks about a French 7GHz one, page one has a Russian 7Ghz scope, and there's lots of other goodies in between!



Respectfully,
Cliff White, W5CNW
w5cnw@...
On 07/12/2013 09:59 PM, Don Black wrote:
 

I don't think that's what I had in mind. I believe there was mention of it several years ago here when there was discussion of the 7109, third party amplifiers and pushing it's bandwidth to 3 GHz. It might have been discussion around the old 519 without amplifiers, just talking about the tube frequency limit. Does anyone else remember it or are the pixies playing with my mind?

Don Black.

On 13-Jul-13 12:32 PM, David DiGiacomo wrote:

 

On Fri, Jul 12, 2013 at 8:25 PM, Don Black <donald_black@...> wrote:
>
>
>
> I think a French company (CSF?) made an analog scope that went to 7 GHz.

Not a scope, and not CSF, but you got the French part right:

http://www.greenfieldtechnology.com/-Data-aquisition-system-.html





Re: 7603 CRT max possible bandwidth?

 

Hi Don,

 

There was no 7109. But you may be thinking of something B&H Engineering (Bernie and Harvey Horowitz, Monroe, NY) made. They modified a Tek 7104 to take advantage of the exquisite 1 V/Div vertical deflection sensitivity of the 3GHz CRT. The did this by removing the entire vertical interface, differential delay line, and vertical amplifier and replacing it with a single ended connection using a proprietary 3GHz amplifier module they developed.

 

They designed two vertical amplifier plugins for it. The M2000 was a 3GHz, 50 ohm plugin and the M3000 was similar except it had a variable delay feature. The output of both plugins was single ended and coupled to the mainframe using a SMB connector. The heart of these two plugins is a single module made from discrete parts for amplification, the 3002, which they designed and sold. The module was not Gaussian. It had terrible overshoot and ringing.

 

They don’t remember if they made 2 or 3 complete systems for the Navy. I have one of each of the vertical plugins. I met with them last month to learn the fate of the mainframes in hopes I could get one donated to the VintageTEK museum but they were given to the Navy for whom they were developed and lost track of them.

 

From the exterior, the 7104 they modified looks exactly like a conventional 7104. If you open one up it would become immediately obvious that the vertical amplifier was removed and replaced with a 2” x 2” module which directly drove the vertical deflection plates.

 

There is no way to verify their claim that this scope was capable of 3GHz. The technology to do that didn’t exist in a form that a small company of their size could afford at that time. Even Tek was unable to confirm the performance of the CRT beyond 3GHz.

 

Dennis

 

From: Don Black, Sent: Friday, July 12, 2013 8:00 PM

I don't think that's what I had in mind. I believe there was mention of it several years ago here when there was discussion of the 7109, third party amplifiers and pushing it's bandwidth to 3 GHz. It might have been discussion around the old 519 without amplifiers, just talking about the tube frequency limit. Does anyone else remember it or are the pixies playing with my mind?

Don Black.


Re: 7603 CRT max possible bandwidth?

 

As far as I know the Tek 7104 CRT is the fastest true CRT that is directly viewed.

 

Most, if not all, of the scopes or CRTs that go faster than 3GHz are indirect display devices that rely on another technology for temporary storage and readout of the data.

 

Dennis

 

From: Don Black, Sent: Friday, July 12, 2013 7:26 PM
I think a French company (CSF?) made an analog scope that went to 7 GHz.
Don Black.


-----Original Message-----
From: David DiGiacomo, Sent: Friday, July 12, 2013 7:33 PM

> I think a French company (CSF?) made an analog scope that went to 7 GHz.

Not a scope, and not CSF, but you got the French part right:

http://www.greenfieldtechnology.com/-Data-aquisition-system-.html


Re: 7603 CRT max possible bandwidth?

 

On Fri, 12 Jul 2013 14:35:37 -0500, David <davidwhess@gmail.com>
wrote:

On Fri, 12 Jul 2013 20:21:10 +0200, "cheater00 ."
<cheater00@gmail.com> wrote:

David,

On Fri, Jul 12, 2013 at 3:03 PM, David <davidwhess@gmail.com> wrote:
The horizontal bandwidth is usually limited by the horizontal CRT
amplifier which is designed for linearity at the expense of bandwidth.

CRT bandwidth is ultimately limited by the deflection plate design.
CRTs faster than the 760x have distributed vertical deflection plates
to support bandwidths above 100 MHz. The 7104 CRT has distributed
horizontal deflection plates to support a 250 MHz horizontal bandwidth
with a horizontal CRT amplifier that looks more like the vertical CRT
amplifier in a slower oscilloscope.

So the 760x CRT should support at least 100 MHz in either direction
and the difference in horizontal and vertical bandwidth is mostly
because of the CRT amplifiers. You could always test it by turning
the CRT 90 degrees and hooking it up.

The 760x CRT bandwidth ultimately depends on the lumped nature of the
deflection plates. You could drive them with a lower impedance
amplifier up to the point where the series inductance becomes a
limiting factor.
Interesting. How far up do you think this will go in terms of vertical
deflection? 200MHz? 400 MHz? What's the fastest oscilloscope with this
type of deflection plate arrangement?
If you study the Tektronix Circuit Concept documents on vertical
amplifiers and CRTs, you can find two different limits on CRT
bandwidth:

1. The lumped deflection plate load on the vertical CRT amplifier will
limit deflection frequency response. The 200 MHz Tektronix CRTs use
impedance matching and CRT terminations to help with this but with
care, I think you could compensate for this in the vertical amplifier.
That would get the 7603 CRT up to at least 200 MHz.

2. The transit time of the electrons past the deflection plates
creates a sin(x)/x type of frequency response. Tektronix CRTs faster
than 200 MHz use distributed deflection plates to get around this
limitation by having the deflection voltage wave pace the electrons.
If this was a problem, then I think you could alter the cathode
voltage to change the electron velocity past the deflection plates and
trade off deflection sensitivity for bandwidth but then the deflection
amplifier would need to produce a higher output voltage to get the
same deflection.


Re: 7603 CRT max possible bandwidth?

Cliff White
 

Here's what I think you're remembering: http://w140.com/kurt/campbell83/

Image 5 talks about a French 7GHz one, page one has a Russian 7Ghz scope, and there's lots of other goodies in between!



Respectfully,
Cliff White, W5CNW
w5cnw@...

On 07/12/2013 09:59 PM, Don Black wrote:
 

I don't think that's what I had in mind. I believe there was mention of it several years ago here when there was discussion of the 7109, third party amplifiers and pushing it's bandwidth to 3 GHz. It might have been discussion around the old 519 without amplifiers, just talking about the tube frequency limit. Does anyone else remember it or are the pixies playing with my mind?

Don Black.

On 13-Jul-13 12:32 PM, David DiGiacomo wrote:

 

On Fri, Jul 12, 2013 at 8:25 PM, Don Black <donald_black@...> wrote:
>
>
>
> I think a French company (CSF?) made an analog scope that went to 7 GHz.

Not a scope, and not CSF, but you got the French part right:

http://www.greenfieldtechnology.com/-Data-aquisition-system-.html




Re: 7603 CRT max possible bandwidth?

Don Black <donald_black@...>
 

I don't think that's what I had in mind. I believe there was mention of it several years ago here when there was discussion of the 7109, third party amplifiers and pushing it's bandwidth to 3 GHz. It might have been discussion around the old 519 without amplifiers, just talking about the tube frequency limit. Does anyone else remember it or are the pixies playing with my mind?

Don Black.

On 13-Jul-13 12:32 PM, David DiGiacomo wrote:
 

On Fri, Jul 12, 2013 at 8:25 PM, Don Black <donald_black@...> wrote:
>
>
>
> I think a French company (CSF?) made an analog scope that went to 7 GHz.

Not a scope, and not CSF, but you got the French part right:

http://www.greenfieldtechnology.com/-Data-aquisition-system-.html



Re: 7603 CRT max possible bandwidth?

David DiGiacomo
 

On Fri, Jul 12, 2013 at 8:25 PM, Don Black <donald_black@bigpond.com> wrote:



I think a French company (CSF?) made an analog scope that went to 7 GHz.
Not a scope, and not CSF, but you got the French part right:

http://www.greenfieldtechnology.com/-Data-aquisition-system-.html


Re: 7603 CRT max possible bandwidth?

Don Black <donald_black@...>
 

I think a French company (CSF?) made an analog scope that went to 7 GHz.

Don Black.

On 13-Jul-13 11:22 AM, Dennis Tillman wrote:
 

The vertical deflection 3dB point of the 7104 MCP CRT exceeds 3GHz.
"Exceeds" is the best Tek was able to determine since measurements at these
frequencies is not easy to do. The vertical distributed deflection plates
have a 200 ohm impedance.

Lockheed took an off the shelf 7912 CRT and used it as the heart of a soft
X-ray detector. They measured the vertical deflection 3dB point of the 7912
CRT as 3.5GHz.

The Horizontal bandwidth of the entire 7104 horizontal system from the BNC
on a 7A29 is >350MHz which is the only scope I know of with that bandwidth
on the horizontal axis.

I believe LeCroy made a faster CRT at one point. Steve Ditter may be able to
confirm what LeCroy was able to do with their fastest analog scopes.


Interesting. How far up do you think this will go in terms of vertical
deflection? 200MHz? 400 MHz? What's the fastest oscilloscope with this type
of deflection plate arrangement?

Cheers,
Damian



Re: Dsa 600 Series Service Reference software

David DiGiacomo
 

On Fri, Jul 12, 2013 at 6:32 PM, wendell <wendellgreene@comcast.net> wrote:
Hi All I recently received a DSA 602A and in the process of buying a hard copy of the Service reference I found tucked inside in a plastic holder a Looks Like New 5.25 floppy disk with this Title DSA 600 Series Service Reference Checks and Adjustments software. It's a Tektronix Logo and 1991 copyright.Part Number 063-0112-02 version 1.1 Disk 1 of 1.
If anyone is interested and still has an IBM 5150 or some other way to read this it's yours if I can have a copy either 3.5 floppy or download. If it's already out there I can't find it.
I have it on my website:

http://www.davmar.org/TE/TekDSA600/service.zip


Re: 7603 CRT max possible bandwidth?

 

The vertical deflection 3dB point of the 7104 MCP CRT exceeds 3GHz.
"Exceeds" is the best Tek was able to determine since measurements at these
frequencies is not easy to do. The vertical distributed deflection plates
have a 200 ohm impedance.

Lockheed took an off the shelf 7912 CRT and used it as the heart of a soft
X-ray detector. They measured the vertical deflection 3dB point of the 7912
CRT as 3.5GHz.

The Horizontal bandwidth of the entire 7104 horizontal system from the BNC
on a 7A29 is >350MHz which is the only scope I know of with that bandwidth
on the horizontal axis.

I believe LeCroy made a faster CRT at one point. Steve Ditter may be able to
confirm what LeCroy was able to do with their fastest analog scopes.

<snip>
Interesting. How far up do you think this will go in terms of vertical
deflection? 200MHz? 400 MHz? What's the fastest oscilloscope with this type
of deflection plate arrangement?

Cheers,
Damian


Dsa 600 Series Service Reference software

wendell19430
 

Hi All I recently received a DSA 602A and in the process of buying a hard copy of the Service reference I found tucked inside in a plastic holder a Looks Like New 5.25 floppy disk with this Title DSA 600 Series Service Reference Checks and Adjustments software. It's a Tektronix Logo and 1991 copyright.Part Number 063-0112-02 version 1.1 Disk 1 of 1.
If anyone is interested and still has an IBM 5150 or some other way to read this it's yours if I can have a copy either 3.5 floppy or download. If it's already out there I can't find it.
Thanks
Wendell


Re: Replace 6BW4 tubes with silicon diodes in a 575

Ed Breya
 

If 6BW4 has an an octal base, you could easily wire up a solid state replacement onto an old base, including series resistor(s). If/when the tube goes bad, just pop out the bulb and put in the new stuff.

Ed

--- In TekScopes@yahoogroups.com, "lindberg.adam" <adam.lindberg@...> wrote:

Hi

yes Im aware about the voltage drop in tube rectifiers.

that might be a reason not to switch to silicon because of the physical size of the resistor that is needed

But I will do some measurements and see, the data for 6bw4 says 40v voltage drop at 100mA load.



--- In TekScopes@yahoogroups.com, "Ed Breya" <edbreya@> wrote:

Yes, the traditional way to upgrade from tubes and selenium to modern rectifiers was to add series resistance to approximate the original characteristics. You should measure the various voltage drops and supply ripple before and after the change.

Ed

--- In TekScopes@yahoogroups.com, "Michael A. Terrell" <mike.terrell@> wrote:

lindberg.adam wrote:

Is it advisable to replace the 6BW4 tubes in the rectifier with 1N4007
diodes ?

why did they use 6BW4 tubes in the 300v and -150v supply but not in
the 100v supply?

Is it just a matter of the higher current draw in the 100v supply and
therefor the need for bigger rectifier tubes and the lack of space for
that, and the size of the early selenium diodes and the lack of space
for them.

If thats the case It would be an easy task to replace the rectifier
tubes with two diodes today. and eliminate two tubes in the circuit.

The tube has a higher voltage drop than silicon diodes so you'll have
to either add a dropping resistor, or let the regulator dissipate
circuit more heat due to the higher voltage


Re: Missing files

Nick
 

Thank, they work fine now - how strange. Don't know what you did, but please keep on doing it!
Nick


Re: Missing files

teamlarryohio
 

The files, at least 'Troubleshooting.pdf' are there, but something's
broken. Maybe they've lost their mime_type? Firefox brought the pdf
down, but didn't know which app to hand it to to open. ...and the
icon in the web UI was a question mark. Try a
right-click-save-target-as instead. Then open it locally. I quit
really trying to second guess Yahoo years ago.
-ls-

"Nick" <nfeakes@hotmail.com> wrote:

I was looking through the "Files" list and quite a number of them are
"not found". For example, Troubleshooting.pdf
Nick



------------------------------------

Yahoo! Groups Links



Missing files

Nick
 

I was looking through the "Files" list and quite a number of them are "not found". For example, Troubleshooting.pdf
Nick

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