I am Saticon

Forum for discussion of electronic television. Generally, stuff to do with CRTs and not using mechanical displays.

Postby AncientBrit » Fri Oct 05, 2012 5:22 pm

Hi Harry,

I'm attaching a clearer pdf version of the circuit.

The tube heater reg is set to +7.6v with a safety dropper 18R to produce around 5.8v across the heaters, so the tube heater is nominal 6.3v.

The reason I chose this arangement was I'd just burnt out a heater on a 1inch vidicon and I wanted to limit the inrush current.

I could have configured the voltage reg to be constant current but I felt this was safer limiting inrush br resistor.

(Not sure if the forum will accept a pdf)

Regards,

Graham
Attachments
NBTV_Saticon_Camera_Circuit.pdf
NBTV saticon circuit
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Postby AncientBrit » Fri Oct 05, 2012 5:31 pm

Hi Harry,

Here are some pixs of the camera I took last night.
(I'm no great shakes as a photographer)

Cheers,

Graham
Attachments
Saticon Camera 3.jpg
Saticon Camera 3.jpg (65.62 KiB) Viewed 9936 times
Saticon Camera 4.jpg
Saticon Camera 4.jpg (97.44 KiB) Viewed 9936 times
Saticon Camera 5.jpg
Saticon Camera 5.jpg (62.93 KiB) Viewed 9936 times
Saticon Camera 10.jpg
Saticon Camera 10.jpg (58.13 KiB) Viewed 9936 times
Saticon Camera 12.jpg
Saticon Camera 12.jpg (74.14 KiB) Viewed 9936 times
Saticon Camera 13.jpg
Saticon Camera 13.jpg (79.05 KiB) Viewed 9936 times
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Postby Harry Dalek » Fri Oct 05, 2012 11:39 pm

AncientBrit wrote:Hi Harry,

I'm attaching a clearer pdf version of the circuit.


Thanks for that Graham its much easier to understand looking at this PDF ! i can read what one or 2 of the ics are now that were to poor to read in the old news letter.

The tube heater reg is set to +7.6v with a safety dropper 18R to produce around 5.8v across the heaters, so the tube heater is nominal 6.3v.

The reason I chose this arangement was I'd just burnt out a heater on a 1inch vidicon and I wanted to limit the inrush current.


Yes you have to get it right i think every one has had that loss on a tube of some sort ...; ( i just finished my heater circuit had to give it a good heat sink seems to work good on a tube i am testing on.

I could have configured the voltage reg to be constant current but I felt this was safer limiting inrush br resistor.

(Not sure if the forum will accept a pdf)

Regards,

Graham
[/quote]

It worked fine graham i am having a good look at it !

I made a mistake in my power supply on the top voltage multiplier circuit ,i had to put in a 3rd transformer using as is with 2 transformers i was shorting out the high voltage when i grounded the negative so i just gave it its own transformer that fixed that problem .
Attachments
Picture 038.jpg
Picture 038.jpg (355.31 KiB) Viewed 9929 times
Last edited by Harry Dalek on Sun Oct 29, 2017 7:36 pm, edited 1 time in total.
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Postby Harry Dalek » Fri Oct 05, 2012 11:48 pm

AncientBrit wrote:Hi Harry,

Here are some pixs of the camera I took last night.
(I'm no great shakes as a photographer)

Cheers,

Graham


OH that's one nice looking camera Graham !!! very neat work looks like its factory made model !

If i get mine going i think it will only look like a poor cousin

:( still its good to try .

Thanks again graham its very inspirational !
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Postby AncientBrit » Sat Oct 06, 2012 1:39 am

Harry,

In pix 5 you'll see at the end of the chassis my warning to myself about 1000v !!

Just in case I forget.

The HV multiplier caps are not shrouded so I have to be careful.

Again Harry be careful with the High voltages!!

Kind regards,

Graham
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Postby Harry Dalek » Sat Oct 06, 2012 9:43 am

AncientBrit wrote:Harry,

In pix 5 you'll see at the end of the chassis my warning to myself about 1000v !!

Just in case I forget.

The HV multiplier caps are not shrouded so I have to be careful.

Again Harry be careful with the High voltages!!

Kind regards,

Graham


Yes thats a good idea ! i think i will do the same for future me !.

Warnings like that are good ..i am also going to put in a colour wiring to voltage decode under the lid..some of the other voltages could hurt to the touch as well..good thing they all drop very fast on switch off.

I didn't think of the camera part i will see if i can get the saticon under some sort of casing because i went for a 50hz transformer at the start i wanted it to be a cabled power supply to what ever i was going to do to the camera ...starts to get messy if you don't think these things out.
I can see your thinking when you made your camera size housing type of power to it how its all going to fit ,its something or a part of our hobby the casing part have to learn .
I will try and use what i have got .
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Postby Harry Dalek » Sat Oct 06, 2012 5:39 pm

just an update was thinking this case might be what i need to start on the project .
The case is recycled from a power supply from a`70s teleprinter least i have something to work on now...
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Picture 040.jpg
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Postby Steve Anderson » Sat Oct 06, 2012 6:06 pm

AncientBrit wrote:The reason I chose this arangement was I'd just burnt out a heater on a 1inch vidicon and I wanted to limit the inrush current. Graham


It's something that is wise to check. The little 1" CRT display used a tube which every datasheet I was able to find on it, from several manufacturers, listed the heater as 6.3V @ 600mA. I needed to drop the nominal voltage of the 12V battery via a resistor.

For some reason I cannot fathom I actually checked the heater current at 6.3V. It was only 300mA. Had I gone ahead and put the calculated resistor in circuit and applied 12V...goodbye CRT!

Over a period of time improvements in cathode coatings resulted in less heater power being required. This is all well and fine in a standard 6.3V parallel arrangement, no real changes required. There's no type suffix on the tube or packaging to indicate the change in heater specs.

Steve A.
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Postby Harry Dalek » Sat Oct 06, 2012 6:28 pm

I always wonder why 6.3 volts for valves and why it never really changed over the years ..good to have a standard .
My camera data on the saticon says 6.3volts also for the heater but in those days a 5 volt regulator perhaps might of been easier ..i am taking the better safe than sorry path and keeping it below 6 volts never know....taking Graham project saticon as a guide to powering mine.
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Postby Steve Anderson » Sat Oct 06, 2012 7:04 pm

harry dalek wrote:I always wonder why 6.3 volts for valves and why it never really changed over the years ..


Harry..err, error. There's almost any heater voltage you can think of. Agreed 6.3V was perhaps (maybe) the most common, but by heck there's so many. Choose a heater voltage, any voltage between 1.2V and 117V and there'll be a tube made for it. I don't include industrial tubes (RF heating, transmitters etc.).

However after WWII things did settle down a bit and with the exception of current specified tubes which all had the same current (say 300mA) but different voltages, 6.3V and 12.6V were the most common.

To keep costs down the current-specified tubes were designed that you put all the heaters in series and if you were lucky as you designed your TV or radio they added up uo your mains supply, either a nominal 120V or 240V.

This meant you could do without the heater winding on a power transformer (if the set used one at all!) thus saving costs, weight, size...

European tubes that started with a 'P' were 300mA heaters, e.g. PCL82, with a 'U' 100mA, e.g UF86 and so on..

Anyway Harry, take care with the heater. Tubes generally can take a lot of abuse...except in the heater...one could say it's their 'nether region'!!

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Postby Harry Dalek » Fri Oct 12, 2012 12:02 pm

Been soldering and testing away last few days and finsihed the clock and timing circuits for the deflection yoke and such posting here the circuit plus changes i have made ....I am making Grahams design after seeing it and studying it i think its well worth making....i have made a few changes here and there .....i have all the parts so just a matter doing it .

In the news letter Graham was wondering if the 4528 monostable would could replace the 4098 and i am using that ic as i couldn't get the 4098 version and seems to would fine .

For the clock i am using a 555 timer and 2 7490s which gives in this circuit 50hz which i have replaced the line voltage and Lm311 to give the same result .

I am making the deflection circuits tonight my next stage ...
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Picture 049.jpg
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Screen 00001.jpg
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Screen 00013.jpg
Screen 00013.jpg (38.48 KiB) Viewed 9865 times
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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Postby AncientBrit » Wed Oct 17, 2012 5:25 pm

Harry,

Please find attached a re-draw of the circuit.

No circuit changes, just cleaned up the transistor outlines etc.

Cheers,

Graham
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NBTV_Vidicon_Camera v2.pdf
Redraw of circuit
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Postby Harry Dalek » Wed Oct 17, 2012 7:11 pm

AncientBrit wrote:Harry,

Please find attached a re-draw of the circuit.

No circuit changes, just cleaned up the transistor outlines etc.

Cheers,

Graham


Thanks Graham you must be a mind reader i just swapped my laptops and needed the pdf on this one so was just about to look for it on the forum and you posted another !

An up date where i am i lost 2 4528s funny enough just one side ,i dropped the voltage to it from 12 to 5 volts and seems ok now no loss of this monostable...i see putting in a pot on pin 11 of the 4046 you can fine tune it to get the 400 hz or change the frequency up or down...for some reason it was just below 398hz putting a trimmer in seems to have fixed this i was thinking the 50 hz clock would need adjusting but didn't seem to matter .

One thing i have been meaning to ask is the head amp pretty much similar to mechanical television where the output of the sensor to the head amp in a shielded metal case ......close as possible the target from the saticon in this case .

Also are the values of the 2 zener diodes on the cathode 2 15 volt ?

Still working on the deflection circuits i could not get the main driver ic for the yoke coils but got some thing similar so might have to change a few things here as it doesn't seem to give the same result just copying the circuit..so i might change it a bit .

A review of your new circuit outlines and such i noticed i have made a mistake in the deflection circuit so perhaps this must be the problem.
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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Postby Harry Dalek » Wed Oct 17, 2012 9:31 pm

Hi Graham if your out there

:wink:

I am getting the waveforms as in your schematic but upside down i have checked the 400 hz pulse coming from pin 9 of the 4528 monostable is correct way around and it is same as your monostable ...i don't suppose its much of a problem just have to reverse the connections i hope its not tube i can turn upside down as its locked in the lens in a one way connection...

I was wondering if the = + pins 2 and 3 of the opamp TL071 are the right way around in the schematic due to the reversed waveform ?

I am using the LM1875 as the yoke driver and i am using a BC557 as the BC477 replacement best i could come up with in my junk box...

I Also finding the voltage to the opamp needs to be 5 volts will not work on 12 volts i am thinking the transistor is the trouble maker unless those pin connections to the opamp have something to do with it..

Either way i will plod on and make the 12 hz side and see what happens.
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Screen 00000.jpg
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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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Postby AncientBrit » Thu Oct 18, 2012 10:58 pm

Hi Harry,

I tried running the scan generator op amps off 5v but had no success so hence the +12v rail to each of them.

I think that's why your waveforms are not the same as mine.

The tube cathode has two zeners 13 volt and 16v in series to produce around 30v.

The BF259 sits across these and produces a 30v beam flyback blanking.
I missed updating the outline for the BF259, it's not clear but the emitter is connected to 0v, and collector to the +30v of the zeners.

Cheers,

Graham
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