The Mongrel

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Re: The Mongrel

Postby Klaas Robers » Wed Oct 27, 2021 11:28 pm

Yes this was the LDK-3 camera. You see the three deflection units for the 3 plumbicons, Red at the top, green in the middle, blue at the bottom. On the side of these deflection units, the flat black boxes with many holes in it, are the pre-amplifiers with each two nuvistors as an input stage. The other parts is all transistors. The thick cable contains 96 wires, going to a rack with electronics, the camera itself is kept as stupid as possible. This camera comes from about 1970.
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Re: The Mongrel

Postby Harry Dalek » Thu Oct 28, 2021 9:06 am

Klaas Robers wrote:Yes this was the LDK-3 camera. You see the three deflection units for the 3 plumbicons, Red at the top, green in the middle, blue at the bottom. On the side of these deflection units, the flat black boxes with many holes in it, are the pre-amplifiers with each two nuvistors as an input stage. The other parts is all transistors. The thick cable contains 96 wires, going to a rack with electronics, the camera itself is kept as stupid as possible. This camera comes from about 1970.


Simple as possible i think you mean ? i suppose very compact for some thing like a studio camera splitting the image 3 ways and lining up optically must of been very precise like every thing all that work for a limited life time .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Mongrel

Postby Harry Dalek » Thu Oct 28, 2021 9:24 am

My power supply checking an earlier stage of the multiplier i have a negative 400 volt which i will adjust to try and match the positive for the deflection amp negative supply .
Be an easy fix if i don't have worry about current matching .

i will scrap the old deflection amplifiers today .
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DSCN6701.JPG
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Mongrel

Postby Harry Dalek » Thu Oct 28, 2021 3:17 pm

Pretty much up to date with what i wanted to do today , i will just wait on any suggestions Steve has on the 12AT7 12XT7 deflection update .
So had a bit of free time and got my tiny Russian valves out and gave 2 a go as a phantastron oscillator ,pretty much working but i just noticed a capacitor rated to low .
Here ramp running about at 90hz ,i was thinking i could see what the results are doing a dual build with any circuits that would work with them , seeing how the tiny valve's work as i build the monitor with normal sized versions ,had to drop the voltage a bit Anode rated at 120v for these .
Adjusted the second pentode valve to work as a triode as in the PDF i posted a while back .
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DSCN6707.JPG
DSCN6703.JPG
Last edited by Harry Dalek on Fri Oct 29, 2021 8:45 am, edited 2 times in total.
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Re: The Mongrel

Postby Steve Anderson » Thu Oct 28, 2021 4:04 pm

Harry Dalek wrote:..I will just wait on any suggestions Steve has on the 12AT7 12XT7 deflection update.

Heck Harry! Somehow that's 'slipped through the cracks', i.e. I forgot about it...I'll get on the case soon...just one other post regarding SSTV to do first...clear some 'real work' stuff, then off I go...

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Re: The Mongrel

Postby Harry Dalek » Thu Oct 28, 2021 4:14 pm

Steve Anderson wrote:
Harry Dalek wrote:..I will just wait on any suggestions Steve has on the 12AT7 12XT7 deflection update.

Heck Harry! Somehow that's 'slipped through the cracks', i.e. I forgot about it...I'll get on the case soon...just one other post regarding SSTV to do first...clear some 'real work' stuff, off I go...

Steve A.


Oh that's ok Steve i was just getting things ready anyway today ,i didn't want to start on the deflection amplifiers as you mentioned to wait due to changes so i was thinking better wait before tackling that .
Any case gave me some time to look at the Russian Valves .
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Re: The Mongrel

Postby Harry Dalek » Sat Oct 30, 2021 3:33 pm

Made the second phantastron oscillator today need to correct timing cap and resistor for the frame frequency as it's a bit off wanted adjustment range here ,the Russian tubes seem to work well in the NBTV range .
I also noticed less frequency drift on the line frequency .
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DSCN6717.JPG
DSCN6727.JPG
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Mongrel

Postby Harry Dalek » Sat Nov 06, 2021 2:16 pm

Steve Anderson wrote:There's more to this change than just altering the supplies...my suggestion (untried)...the +8.0v value will/may alter depending on your ramp amplitude and average voltage. I suggest getting those done before building this...there may be some changes required as a result...

R101, 105, 106 & 109 need to be mounted right on the socket pins.

Steve A.

Deflection 101.gif


Hi Steve
I ended up building one deflection circuit shown for testing i know it needs changes ,just to see how far off and results are .
Measuring the 8v seems way off once the tube starts to work voltage go's up well past positive 100v at the cathode .
The position control acting more as a size control and no correct waveform out the deflection plate points .
I do see a line on half the CRT face but can only be size controlled with the position control .
I wanted to see what the waveform would look like out of the triodes if i just ground the cathode's tried the below ...
If i don't use the negative supply and just ground the cathodes or use a small value resistor to ground a reversed ramp is shown at the plate connections.. anode ,but very similar to the results i got using these triodes before very little crt deflection ...just a very tiny line .
Any thoughts i could try i was thinking next step would be perhaps increasing the R 104 on the cathode or 102 and 103 ? on the plates seems to me if 8v is the goal to see at the cathode .
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Deflection 101 (2).gif
Deflection 101 (2).gif (55.34 KiB) Viewed 1523 times
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Re: The Mongrel

Postby Steve Anderson » Sat Nov 06, 2021 6:22 pm

OK, let's see. What positive and negative voltages do have available?
What tubes are you planning to use in these stages?

That's a start, the ECC91s as illustrated are very different to what you may have on hand, it was just an example...

Also if you can provide the ramp amplitudes available, both peak-to-peak and absolute values would help (min. +2, max +10, 8V p-to-p, or similar).

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Re: The Mongrel

Postby Harry Dalek » Sat Nov 06, 2021 8:44 pm

Steve Anderson wrote:OK, let's see. What positive and negative voltages do have available?
What tubes are you planning to use in these stages?


Hi Steve i have just pulled the power supply board out for further work the positive voltage with the load of all the tubes and crt dropped the original 330v which now seems to be 200v no load to just around 190v using all the circuits ,only using the 130v AC supply in this stage positive stage so will rework the supply ,see whats up here.

I want to get back up to the 300's with load so will work on that this week

That's a start, the ECC91s as illustrated are very different to what you may have on hand, it was just an example...


The 12AT7 i was using is same as a ECC81 bit different as you say the anode voltage 250v and ECC91 is 100v,yep i know it was an example untested so no problems .

Also if you can provide the ramp amplitudes available, both peak-to-peak and absolute values would help (min. +2, max +10, 8V p-to-p, or similar).


Ok look into that one it might be better to get the supply back to a useable range before giving numbers as they will change after i adjust the power supply .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Mongrel

Postby Harry Dalek » Sun Nov 07, 2021 8:07 am

Well checking the supply its fine i found my meter is faulty ! way off checking with my new meter and another both showing the positive supply is 370v the faulty 200v, 370v no load was correct when i built it ...oh well dc supply is fine check the battery on the faulty meter but i think its going in the bin .
With load 335v thats supplying 6 working tubes and the CRT at the moment .
So 335v ...i will look into the other numbers Steve
I am not sue if i got the peak to peak side of measuring right with the scope but giving me on maximum ramp 1.4v on the line and 671mV frame probes both on 10X scope set to 10x same reading if scope set to ac or dc
2v per div on this setting both ramps showing maximum amplitude
On the crt hv negative supply i could tap off this voltage from earlier section of the high voltage multiplier i have a 470v section as i was trying but with a higher ohm resistor to drop it more .
Attachments
DSCN6730.JPG
DSCN6732.JPG
DSCN6731.JPG
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Mongrel

Postby Steve Anderson » Sun Nov 07, 2021 1:26 pm

Hmm, the use of attenuating probes on 'scopes does cause a bit of confusion to those new to using them. I suggest finding a couple of 'voltage references' such that you can ensure you've 'got it right' in your head. This is made worse by more modern 'scopes often doing it for you. Some sense you're using a x10 probe and do the adjustment for you, some don't. A potential source of (large) errors. Often it's obvious, you're unlikely to get 60V out of a circuit running off a 9V battery unless it's designed to do that. If still slightly unsure use a meter for DC or low-frequency signals to confirm or otherwise what you might find.

Use a 9V battery (on DC-coupling) as a rough reference and make sure the 'scope and/or you get it right. Or a transformer with a (say) 12V secondary where the peak-to-peak voltage should read about 34V p/p, maybe up to 20% more with no load.

I had to make some adjustments in my head when I encountered this on a digital 'scope for the first time. Below is an example from my 'scope. The x10 setting in the right-hand column can be changed to x1, x10, x100 and x1000 for really high voltages. So the voltages at the bottom are the 'real' volts-per-division voltages, no need to multiply them x10 in your head...

Steve A.

TEK0060.gif
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Re: The Mongrel

Postby Steve Anderson » Sun Nov 07, 2021 1:29 pm

Yes, check every time you use a meter that the low-battery warning hasn't come on, an easy source of errors and confusion...and also during the time of usage, after 30 minutes it may come on...

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Re: The Mongrel

Postby Harry Dalek » Sun Nov 07, 2021 6:20 pm

Steve Anderson wrote:Hmm, the use of attenuating probes on 'scopes does cause a bit of confusion to those new to using them. I suggest finding a couple of 'voltage references' such that you can ensure you've 'got it right' in your head. This is made worse by more modern 'scopes often doing it for you. Some sense you're using a x10 probe and do the adjustment for you, some don't. A potential source of (large) errors. Often it's obvious, you're unlikely to get 60V out of a circuit running off a 9V battery unless it's designed to do that. If still slightly unsure use a meter for DC or low-frequency signals to confirm or otherwise what you might find.


Well i used my regulated 5 12v power supply checked with multimeter then on the scope with a 5v per div so 5 volt showing one div and 12v showing 2 a bit div, then i hooked the scope back up to the ramps and they are showing up very low ......percentage of the div so Peak to peak might of been correct also low seems very bad for a high voltage circuit to put out some thing what i am seeing little confused here till i remembered some thing ,copying chris longs ramp circuit i left in a 100 k resistor the ramp is passing to a size control which would reduce the ramp size but a large amount i would think ...i will look into that i left it out on the Russian valve version of the circuit i posted a few post back .
Probes and scope set to 10x and DC
(5V test) one per div below
DSCN6734.JPG

DSCN6733.JPG



Use a 9V battery (on DC-coupling) as a rough reference and make sure the 'scope and/or you get it right. Or a transformer with a (say) 12V secondary where the peak-to-peak voltage should read about 34V p/p, maybe up to 20% more with no load.


i will take note and try that

What i am getting does look very low compared to what a 5v DC per div test i will look into this more ,it must be a very low waveform ?

I had to make some adjustments in my head when I encountered this on a digital 'scope for the first time. Below is an example from my 'scope. The x10 setting in the right-hand column can be changed to x1, x10, x100 and x1000 for really high voltages. So the voltages at the bottom are the 'real' volts-per-division voltages, no need to multiply them x10 in your head...


My scope can do that as well but the probe would have to match the scope adjustment then ,i have only seen 1 and 10x probes rather not do the maths bad at it as is :roll:

Yes, check every time you use a meter that the low-battery warning hasn't come on, an easy source of errors and confusion...and also during the time of usage, after 30 minutes it may come on...


I think since the battery low indicator is not on this i think this meter is a dud now for DC tests ,i am happy i picked it up and had other meters to test it against it .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: The Mongrel

Postby Steve Anderson » Mon Nov 08, 2021 11:58 am

If I had got 10-100V peak-to-peak out of that I would have thought, "I guess that's about right." But just 1.5V or so - I'm sure there's something not quite right...is the frequency anywhere near what you're expecting?

Having no experience with this arrangement I'm not much help...

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