The Thylacine higher line rate monitor

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Re: The Thylacine higher line rate monitor

Postby Harry Dalek » Thu Jan 18, 2018 4:16 pm

I have been looking for some sort of case ,the boards wiring are a little annoying laying about ..
Something for this size of project not easy to buy a case for well not locally perhaps on ebay but thought i would go with the Repurposing and went scrounging for some thing cheap at our Sydney road recycling shop .
Problem with cases for a CRT is most cases are to flat so have the Length, Width for the boards but not wanted height...here i found something that's more than big enough and didn't have to even cut a hole for the crt ,its a little beat up with the odd scratch but for 15 bucks with another little portable 12v b/w tv thrown in something i can live with .
CRT fits nice where the cassette tape mechanism went i might of got away with a flatter case but i was more thinking what would fit for sure .
The open slot where the play record rewind fast forward buttons were i will put a panel ,the old panel switches positions where they are now i will repurpose for the monitor also might even be my first monitor with sound with all this Spacious case room !
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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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Re: The Thylacine higher line rate monitor

Postby smeezekitty » Mon Jan 22, 2018 6:50 am

Looks good! Are you going to connect the meters to something then?
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Re: The Thylacine higher line rate monitor

Postby Harry Dalek » Mon Jan 22, 2018 4:58 pm

smeezekitty wrote:Looks good! Are you going to connect the meters to something then?


Yes i suppose since we tend to use one channel as video and the other audio that could be a good use of the meters may as well they are there...so Yep !
i am also repurposing the switch and pot panel i have not made up my mind what yet but i know i need some switch for the line and frame frequencies so they will come in handy the old cassette audio switch and pot panel shown was removed from old circuit board ...bit of work i tell you !...but i was determined.
I had the circuits working off my bench power supply but it needed its own... i i have made this and its mounted in the case ,its wired up and working /
The CRT is now mounted as well
Next i will mount the deflection amplifier and other working boards ,i making so its easy to change a board if need be and adjust .
Should have most of the boards working in this by the end of the week .
Attachments
IMG_0722.JPG
IMG_0718.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 Thylacine higher line rate monitor

Postby Harry Dalek » Thu Jan 25, 2018 7:58 pm

I did hope to have a better report at this stage but finally got the deflection amplifier wired up and i have a deflective transistor ,i think its one of the power transistors ,,i will look into that tomorrow .
EDIT
Ok worked that out was one of the power transistors but my fault i forgot one of the pnp's was earthed to the heat sink so when i mounted it on the case i was pretty much earthing the collector of this transistor causing a short across the negative supply :roll: live and learn,,,
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IMG_0737.JPG
IMG_0729.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 Thylacine higher line rate monitor

Postby Harry Dalek » Fri Jan 26, 2018 9:07 am

Things are looking better today the deflection Amplifiers are working again getting full deflection across the horizontal vertical i have the sawtooth waveform knocked back a bit for the scope raster so lower deflection here at the moment on the Thylacine monitor.
Display i think i have it on 50 hz frame and 400hz line reason for low line number ,
BTW just about all apart from the PCB and a few bits are all junked parts .
Attachments
IMG_0741.JPG
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IMG_0738.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 Thylacine higher line rate monitor

Postby smeezekitty » Fri Jan 26, 2018 10:04 am

I don't know much about CRTs but is there are way to defocus the beam for lower line count? Either that or to make the picture smaller?

When there are big gaps between the lines, it really affects the picture quality
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Re: The Thylacine higher line rate monitor

Postby Harry Dalek » Fri Jan 26, 2018 1:25 pm

smeezekitty wrote:I don't know much about CRTs but is there are way to defocus the beam for lower line count? Either that or to make the picture smaller?

When there are big gaps between the lines, it really affects the picture quality


i have a multi system of line and frame frequencies i can mix to produce different line numbers that mix was 50hz and 400hz so 8 lines .
As you know 12.5hz line frequency 400 32 lines so i can have if i use the pmt cameras DAC circuit that gives me 8 16 32 64 128 256 and a bit more depends on if i use 12.5 25 50 hz as the frame rate ..
That's also here if i use this as a slave monitor a big viewfinder to my PMT camera which i will have it so i can switch its sawtooth oscillator's in to the monitors deflection amplifiers .
I also want it to work on its own so i am for a start at least get it to display up to 64 and 128 line from a video signal .
I got to the point here where i had to case it before i could move on so here i was checking how it would work with its own power supply ..those deflection amplifiers are very current hungry .
Your Question on the gaps raster size and such when i started this project i had the same questions but now i know you can adjust all these for low line rates you have to shrink the raster a touch and the lines will match up or if you like a large sawtooth signal to the deflection amplifiers will increase a low line rate system to full screen with gaps .
Line thickness seems to be self adjusting to the size and frequency of the sawtooth waveform fed to the deflection amplifiers ..below is a 625 line monitor nothing changed just feeding a low line rate video to it .
Magnetic CRT's are i think harder than electostatic but i went with this because these have a finer focus for a higher line rate and are smaller and easier to still to find,but like every thing soon these will be rare to in time.
Attachments
IMG_0724.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 Thylacine higher line rate monitor

Postby Harry Dalek » Fri Feb 02, 2018 11:02 pm

I decided to go with Steve's DAC circuit for the sawtooth generator since it worked so well in the PMT camera project and i know it works hooking it up to the monitors deflection circuits .
Only change is i have replaced the 4046 3.2MHZ oscillator with a crystal oscillator ,reason is at these frequencies there is a large amount of drift in frequency with this oscillator ,i did give it another go but i got the same results so again went with a crystal oscillator as in the below schematic ,not sure if i would get the same drifting with another RC oscillator design but i see the 4046 has a constant drift in the MHZ range .
I am not sure if it matters that much or how far off the circuits clock is off frequency for a monitor i wanted a raster when there is no sync ,but just in case better go with an accurate master clock .
I will look into syncing via pin 11 of ic201 line side of the circuit for a start ,i had forgotten Steve designed this that it could be synced so a no brainer to reused this design for the monitor .
Attachments
download (1).jpg
download (1).jpg (12.56 KiB) Viewed 3235 times
Harry%27s Timebase Logic 1.gif
Harry%27s Timebase Logic 1.gif (14.4 KiB) Viewed 3235 times
Line %26 Frame Ramp Generators l.gif
IMG_0748.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 Thylacine higher line rate monitor

Postby Harry Dalek » Sun Feb 04, 2018 7:34 pm

Well a first i had a fair bit of trouble here giving it a test go ,making this circuit before worked first go this time it has tested me and looking at the problem area ic201 ic203 74hc4040 ic's .....so far i have been fault finding the framing side of the circuit and have got it going ,decoupling capacitors did help but again it was really ic203 area that was the trouble maker.
Got a nice sawtooth now out of this side of the circuit ,
Attachments
IMG_0756.JPG
IMG_0754.JPG
IMG_0750.JPG
Last edited by Harry Dalek on Sun Feb 04, 2018 8:45 pm, edited 1 time in total.
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 Thylacine higher line rate monitor

Postby Robonz » Sun Feb 04, 2018 8:30 pm

Harry, your bread boarding skills are looking good, nice to see it working. You got all the caps on too!

One note to be wary of is when you make all those jumper wires really tidy by running them all together you run the risk of cross-talk between the wires. Most of the time it does not matter but occasionally if you have a sensitive high impedance line running close to an output it can wreak havoc and be very hard to find

Well done the waveform looks great.
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Re: The Thylacine higher line rate monitor

Postby Harry Dalek » Sun Feb 04, 2018 9:06 pm

Robonz wrote:Harry, your bread boarding skills are looking good, nice to see it working. You got all the caps on too!

One note to be wary of is when you make all those jumper wires really tidy by running them all together you run the risk of cross-talk between the wires. Most of the time it does not matter but occasionally if you have a sensitive high impedance line running close to an output it can wreak havoc and be very hard to find

Well done the waveform looks great.


I should of really listened to my self before i started as i was going to do a closer copy of the original lay out but i wanted to see if i could do it a touch easier and neater with rats nest wiring ,i hardly ever use it ...But yes when i got nothing at the start and did some fault finding and found all the wiring was correct i was suspecting what you are thinking .
lucky for me all i had to do on checking any ic problem was plug it in the to PMT camera all those checked out fine ...the wire bundle and and some decoupling was the next on the list so far it seems to work fine when the decoupling side was added to the circuit ..
Next the lIne side of the circuit see how that go's now .
Last edited by Harry Dalek on Mon Feb 05, 2018 8:57 pm, edited 1 time in total.
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 Thylacine higher line rate monitor

Postby smeezekitty » Mon Feb 05, 2018 4:26 am

I have to echo what Robonz said. Those are amazing looking boards. Whenever I try to build boards like that, they always look like rubbish.
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Re: The Thylacine higher line rate monitor

Postby Harry Dalek » Mon Feb 05, 2018 9:17 pm

smeezekitty wrote:I have to echo what Robonz said. Those are amazing looking boards. Whenever I try to build boards like that, they always look like rubbish.

Thanks i tend to try to never use or try to use least amount of plastic coated wire as possible .
I use the copper wire strands out of house wiring cable its a nice thickness i find not to thick and not to thin for the matrix board connections between components .
This one due to the amount of wiring i would of had to use a larger matrix board if i wanted to do that all under the board so old rat nest wiring was a easier approach to cut down size of the matrix board but as i found out did cause me grief this time for a while .
I still have to look into the other half of the circuit i did test the frame side on all frequencies frame and line multi system standards it can do so i know this half would work as either /.
when i have some spare time later this week will finish it off and hook it up to the deflection amplifiers .
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 Thylacine higher line rate monitor

Postby Robonz » Mon Feb 05, 2018 9:37 pm

Hi Harry

This is my method I have stuck with for many years. I solder a row of pins down the side of each chip and wire wrap between them. It has been very reliable and there are no wires on the bottom Just some caps like yours, This method is nice as reconfiguration is effortless. Density is high. And you only really solder it once. Another rule I try to stick with is every external wire must be plugable so I can whip the board out when I need to do soldering etc. I solder surface mount resistors and caps between the pins on the bottom too.
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Re: The Thylacine higher line rate monitor

Postby Harry Dalek » Tue Feb 06, 2018 9:06 pm

Robonz wrote:Hi Harry

This is my method I have stuck with for many years. I solder a row of pins down the side of each chip and wire wrap between them. It has been very reliable and there are no wires on the bottom Just some caps like yours, This method is nice as reconfiguration is effortless. Density is high. And you only really solder it once. Another rule I try to stick with is every external wire must be plugable so I can whip the board out when I need to do soldering etc. I solder surface mount resistors and caps between the pins on the bottom too.

Hi Keith
I have never tried this type of wire wrapping but had a tool for years ,i think i went right from twisting components wire to each other to soldering so skipped this idea ..
It is interesting as i am sure every one has their own wiring style of some sort ..i can see yours is good for testing with out wasting solder and you pretty much can keep the tested circuit without having to remake it to solder so its a good idea .
Some times i have flipped the circuit board over and soldered parts on top of the matrix looks messy but the board bottom which really it the top can be screwed right flat to the metal case with out shorting any thing ...suppose there's lots of ways to do the same thing as long as it works doesn't matter ...i do find soldering therapeutic :mrgreen:
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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