Neville Michie wrote:
Is this calibrator gated?
Back in the stone age when I started work, a CRO (with a 5BP1 tube in
it) was calibrated in time by a gated oscillator
that put little pips on the trace at 1 microsecond intervals.
So that the markers would not crawl across the screen the
I was probing at the cathode not at G1 FWIW.
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Bruce Griffiths
Sent: 10 September 2008 03:14
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Ancient OCXO in scope calibrator
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Ancient OCXO in scope calibrator.
On Tue, 9 Sep 2008 19:19:39 +0100, David C. Partridge
[EMAIL PROTECTED] wrote:
Following the good advice I received about increasing the value of the
trimmer capacitor, I replaced
September 2008 01:20
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Ancient OCXO in scope calibrator.
I was just sitting here thinking about the oven problem. If you replace the
thermostat with the proper power PTC thermister, you could make the oven
linearly regulate
Of Neon John
Sent: 10 September 2008 01:20
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Ancient OCXO in scope calibrator.
I was just sitting here thinking about the oven problem. If you replace the
thermostat with the proper power PTC thermister, you could
-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of David C. Partridge
Sent: 10 September 2008 18:12
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Ancient OCXO in scope calibrator.
Now that's an interesting thought.
How should one go about
Following the good advice I received about increasing the value of the
trimmer capacitor, I replaced the trimmer which was originally
3-12pF, with
another one which was 2-22pF.
This has given the additional adjustment range to allow me to pull the
crystal to meet the specification.
It's
and frequency measurement
Subject: Re: [time-nuts] Ancient OCXO in scope calibrator.
You might have an intermittent solder joint or component lead that's being
flexed when you touch various points with the probe. Does a plastic
alignment tool cause the same behavior?
Or, more likely, there's so much loss
Thomas A. Frank wrote:
A ceramic alignment tool doesn't cause the same behaviour, but a
probe sure
does.
Something is whispering grounding.
I'm not sure why, but that is where I would start looking...
Tom Frank, KA2CDK
This particular variant of the miller oscillator uses
On Tue, 9 Sep 2008 19:19:39 +0100, David C. Partridge
[EMAIL PROTECTED] wrote:
Following the good advice I received about increasing the value of the
trimmer capacitor, I replaced the trimmer which was originally 3-12pF, with
another one which was 2-22pF.
I would leave the same trimmer in there
How's the filament voltage at the 7587 socket, by the way? A shorted
turn in your power transformer might account for some lack of
enthusiasm on the Nuvistor's part.
I'd expect a shorted turn on a power transformer to let the smoke out.
--
These are my opinions, not necessarily my
Is the screen grid bypassing still effective?
If this is marginal the oscillator may exhibit the described sensitivity
to loading at grid 1.
Bruce
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How's the filament voltage at the 7587 socket, by the way? A shorted
turn in your power transformer might account for some lack of
enthusiasm on the Nuvistor's part.
I'd expect a shorted turn on a power transformer to let the smoke out.
Depends on a lot of things, but yes, usually.
Is this calibrator gated?
Back in the stone age when I started work, a CRO (with a 5BP1 tube in
it) was calibrated in time by a gated oscillator
that put little pips on the trace at 1 microsecond intervals.
So that the markers would not crawl across the screen the oscillator
was stopped
and
Dave, Bruce,
Need a few more circuit details.
The crystal current wont be very high unless their are other components
connected to G1.
As expected, BAMA can assist:
http://bama.edebris.com/manuals/tek/184/
I am thinking about undamped overtones/other modes of the crystal and
similar.
Magnus Danielson wrote:
Dave, Bruce,
Need a few more circuit details.
The crystal current wont be very high unless their are other components
connected to G1.
As expected, BAMA can assist:
http://bama.edebris.com/manuals/tek/184/
I am thinking about undamped overtones/other
.
Cheers
Dave
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Bruce Griffiths
Sent: 07 September 2008 23:38
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Ancient OCXO in scope calibrator.
Dave
Need a few more circuit
] [mailto:[EMAIL PROTECTED] On
Behalf Of Bruce Griffiths
Sent: 07 September 2008 23:38
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Ancient OCXO in scope calibrator.
Dave
Need a few more circuit details.
The crystal current wont be very high unless
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Bruce Griffiths
Sent: 08 September 2008 08:41
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Ancient OCXO in scope calibrator.
Magnus Danielson wrote:
Dave, Bruce,
Need
Brooke Clarke wrote:
Hi Dave:
Do you have a photo?
It's been my experience that older electronic equipment fails because of poor
connections rather than bad components. For many examples see:
http://www.prc68.com/I/HaT.shtml
Have Fun,
Brooke Clarke
Brook,
A little off topic from
Rex wrote:
Brooke Clarke wrote:
Hi Dave:
Do you have a photo?
It's been my experience that older electronic equipment fails because of
poor
connections rather than bad components. For many examples see:
http://www.prc68.com/I/HaT.shtml
Have Fun,
Brooke Clarke
Brook,
I'm having some problems with an ancient Bulova OCXO in a Tektronix 184
'scope calibrator.
This is an crystal mounted on an octal valve base with a heater winding
wrapped round it, and a common or garden variety thermostat which is
supposed to switch at 75 celsius. I've not measured the
G. email failure, maybe a repeat:
I have one of those oscillators in a tek 184 that I do not use anymore.
Those calibrators are really cool, I used one for a long time when I first
started tinkering.
If you need it, you can have the oscillator. ([EMAIL PROTECTED])
Good luck!
Still needed HP
David C. Partridge wrote:
I'm having some problems with an ancient Bulova OCXO in a Tektronix 184
'scope calibrator.
This is an crystal mounted on an octal valve base with a heater winding
wrapped round it, and a common or garden variety thermostat which is
supposed to switch at 75
Dave
Need a few more circuit details.
The crystal current wont be very high unless their are other components
connected to G1.
Bruce
The anode G1 capacitance is about 10fF so with 25V rms at the anode, the
crystal current would be around 16uA if the circuit relies on feedback
via
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