Quote from: picowatt on April 26, 2012, 01:15:55 AM
TK,

Just let it go.  I'll fight my own battles if I feel it's called for.

In this case, not so much...

Regarding your scope, does that -3000 really go thru the filament transformer or were you saying the filament winding was shorted to the -3000?

Back in the day, when we all watched big glass bottles, filament shorts were common and all manner of filament iso's and brighteners were available.

PW

The -3000 really really does go through the filament of the CRT and thus through the winding of the mains transformer.

The HV was leaking out inside the transformer and loading up (or drawing down, ha ha) the regulated + and - 100 v and +250 v supplies so that they died, and for some strange reason the filaments of the preamp tubes are also run off this regulated supply. It took me a while to track it down, I didn't want to believe the mains transformer was bad and I sure didn't want the CRT to be bad, but there it is. I know I'll never find another mains transformer for it... but my kludge seems to be working and there isn't any other HV in the mains transformer (unless you count 190 vac, which I don't.)

So now I have my Lissajous machine again... and for LF signals it can be used in a differential mode, as you know.

Quote from: TinselKoala on April 26, 2012, 01:16:23 AM
Yep, that's what the burn-in is for. If it fails, it will be in the same condition it was when I started, but so far so good, it's been up four hours now....
I got this one directly from NASA Ames. A colleague is a chief scientist there and he picked it up at a surplus disposal auction along with a bunch of other neat stuff, and gave it to me.
The surplus store I deal with here does not have a website, no. And they don't really have much. Two of my three favorites are in Canada:
http://torontosurplus.com/
http://www.activesurplus.com/
The first is run by someone who knows what he's got and charges full market rate but will ship to the States. The second is wild and crazy, you never can tell what they will have and there are some good deals there. Also will ship stateside I believe.
And the third was in the Bay Area in CA: Mike Quinn's, but it's been closed for years now.
Around here there isn't really much to choose from, even though we have 5 or six military bases or ex-bases nearby.

TK,

I am familaiar with the first store, and they are as you say, they know what they have and price accordingly.

Most of the great surplus stores for electronics I used to haunt have all clsosed as well.  Back in the day when discrete was being phased out and NASA was at full bore, there was an incredible amount of surplus available.  Then as surface mount was being phased in, a whole new batch of surplus was available.  Seems that now, as mfg. has moved overseas, most surplus stores have dried up.  I think the military just scraps and chops all their gear now.

PW 

TK,

If the RS transformer fails, I'll bet you could find one with a better isolation rating.

Maybe a nice potted toroid or similar.

PW

Quote from: Rosemary Ainslie on April 25, 2012, 10:26:11 PM
Groundloop,
Actually what you've pointed to is that the signal from the supply source and the batteries are 'in series' during the application of a negative signal at Q1.  There is no-one would argue.  I agree.  Wholeheartedly.  And, as I pointed out in my previous post - this is continual during an extended switching phase of the function generator.  We literally apply this negative signal for upwards of 2 minutes.
I am not sure how the Colpitt's oscillator runs.  But I believe it does not use MOSFETS - and therefore does not 'typically' have that internal body diode and the 3 pin connection to the circuitry and signal generator - simultaneously.  Are you saying that one MOSFET - on its own - would then enable that 'Colpitt's oscillation'?  What I DO know is that we can, indeed, just use the one transistor - as Poynty Point's already confirmed.  And that we then only need to apply a continual positive signal to the source rail of the battery supply to generate that oscillation.  Which is one of the tests that we've got lined up to show you all.  So.  I can't comment regarding that Colpitt's oscillation analogy.  But you're CERTAINLY correct in that continual oscillating waveform as a consequence.
It's not the only thing Groundloop. Quite apart from the evidence of a negative voltage at the 'onset' of that oscillation - is the fact that we measure that negative wattage.  That's pivotal.  But I like your 'style' of argument.

Kindest regards,
Rosie

Rosemary,

You can build oscillators by using MOSFETS also. You operate the MOSFET in the linear region just like an bipolar transistor.
I state then when the FG is at negative offset then the left MOSFET is biased and can operate in the linear region like an oscillator.

The 180 degrees feed back needed to get the oscillation going is through the D to S capacitance (inside the MOSFET).

The LC tank circuit needed is the self inductance in RLOAD and self capacitance in RLOAD plus inductance in wires. I have
made an drawing explaining different Colpitts oscillator variations. I think my drawing proves that your circuit oscillate
as an Colpitts configuration when the FG is at the negative, thus giving a positive bias voltage to the MOSFET that allow
an oscillation to happen.

So I will stay by my earlier statement that your circuit oscillates (when the FG is at negative pulse) because
it is an Colpitts oscillator setup.

GL.

picowatt?

Quote from: picowatt on April 26, 2012, 01:15:55 AM
TK,

Just let it go.  I'll fight my own battles if I feel it's called for.

In this case, not so much...

Regarding your scope, does that -3000 really go thru the filament transformer or were you saying the filament winding was shorted to the -3000?

Back in the day, when we all watched big glass bottles, filament shorts were common and all manner of filament iso's and brighteners were available.

PW

I take it then that you're not 'up for it'?  You realise that those two questions are the ONLY questions that actually pertain.  And they're the only two questions that have not yet been addressed.  All that emphases that you've all relied on related to my innate stupidity - all that?  They're irrelevant to the argument.  What's needed is some kind of reasonable explanation for the evidence of a negative wattage that is dependably and accurately measured over a circuit.  And then some discussion as to why.  TK.'s experiments were designed to 'infer' gross measurement errors.  And Groundloop has come up with the proposal that it may be a mere 'oscillation' that has no intrinsic benefit.  So.  Let's hear your 'summation'?

And TK - I always run a spell check.  You Americans - unfortunately - have yet to learn how to spell.  In fact, you've made 'misspelling' English into an art form - since you re-invented it - with your Declaration of Independence.  There's an excessive use of 'z's and an omission of 'our' in the suffix of certain nouns - to be represented as 'or'.  But on the plus side - you all make English sound SO delectable - who cares? 

Kindest regards to you both and comforting to see that TK is still 'abusing' all those forum guidelines.  But no doubt he's in need of all that propagandising. So it's to be expected.  It's becoming a bit repetitive though TK.  People will start 'skimming' your posts - like I do with your videos.

Again.
Rosie Pose