The PMT in control of the Devil

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Re: The PMT in control of the Devil

Postby ppppenguin » Thu Aug 17, 2017 6:10 pm

Now you know why I don't fully trust frequency meters:-) It's not the basic accuracy** which may or may not be good enough for a given job but mistriggering which you seem to be suffering here.

What probe(s) were you suing with the scope? They make a big difference at higher frequencies.

**Basic accuracy even with a rubbish meter is hardly likely to be worse than 100ppm or 0.01%.
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Re: The PMT in control of the Devil

Postby Steve Anderson » Thu Aug 17, 2017 6:45 pm

Well, that basically seems to be working OK, but you do have some ringing/overshoot which could be down to ground/0V runs and/or scope probe problems. You should be using a x10 probe to reduce the capacitive loading on the circuit. Otherwise the 4040 appears to be doing its job. So I think you can assume that the two LCD 'scopes' are useless at anything above high audio frequencies, or at least the frequency counter part is. No surprise really.

Having got that out of the way what is the frequency at pin 1 of the 4040? Is it still 6.6kHz? Is the Freq. pot centred? What is that frequency at either end of the pot track, clockwise and anti-clockwise?

The labeling of the pins is just down to each manufactures whim. In the two shown Q0=QA, Q1=QB and so on, there's no other difference, just the naming.

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Re: The PMT in control of the Devil

Postby Harry Dalek » Thu Aug 17, 2017 8:04 pm

ppppenguin wrote:Now you know why I don't fully trust frequency meters:-) It's not the basic accuracy** which may or may not be good enough for a given job but mistriggering which you seem to be suffering here.

What probe(s) were you suing with the scope? They make a big difference at higher frequencies.

**Basic accuracy even with a rubbish meter is hardly likely to be worse than 100ppm or 0.01%.


I have to have a look at the probes off hand i am not sure of the make but i might still have something with its maker onit ..

Pretty much for the high frequencies the 20mhz scope was on its highest range ...i was not sure why the probe problem i can swap them around and see .

But pretty much showed the 4040 is ok i am happy here i will not blame it now .
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 PMT in control of the Devil

Postby Harry Dalek » Thu Aug 17, 2017 8:44 pm

Steve Anderson wrote:Well, that basically seems to be working OK, but you do have some ringing/overshoot which could be down to ground/0V runs and/or scope probe problems.


I didn't worry to much about it here doing the test but something i will look into they should be ok they were first used on the 3bp1 got them new around that time .I noticed it got better as the frequency lowered.

You should be using a x10 probe to reduce the capacitive loading on the circuit. Otherwise the 4040 appears to be doing its job. So I think you can assume that the two LCD 'scopes' are useless at anything above high audio frequencies, or at least the frequency counter part is. No surprise really.


I was on X1 only sorry about that ,i will try and keep that hint in my memory for next time .

Having got that out of the way what is the frequency at pin 1 of the 4040? Is it still 6.6kHz?


Well i did an experiment ....i found another brand 4046 ( it is a cd but worth a shot ! )first took the pin 1 reading with both meters with the new HC 4046 ic's both showed 6.6 khz at pin one and all the strange readings as before i then replace the HC with the found Cd4046 took the same pin 1 reading it was now in the Hz range 611 hz and all the other readings were in range close to what would be expected here with the 4046 running at around 2mhz or so ....i am now blaming the 4046 ics i ordered if one shows what is expected and the other not which would you think is wrong ?

Is the Freq. pot centred? What is that frequency at either end of the pot track, clockwise and anti-clockwise?


Yes i tried that it has a small range ...in the photos below its set at top trimmer range so pin 1 4040 reading is 611 hz Cd 4046 and 7khz HC 4046 !!!!!!!!!!!!!!!!! what the hell ! that a bit of a jump !

The labeling of the pins is just down to each manufactures whim. In the two shown Q0=QA, Q1=QB and so on, there's no other difference, just the naming.

Steve A.


Yes the 4040 seems fine from your suggestion doing the crt scope test i am happy with that but i am very very sure its the HC 4046 giving my trouble .
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Last edited by Harry Dalek on Fri Aug 18, 2017 11:17 am, 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 PMT in control of the Devil

Postby ppppenguin » Thu Aug 17, 2017 10:20 pm

Just a thought. Do you have decoupling caps across the power pins of each chip? You really need 100n on each chip for HC. Inadequate decoupling can cause all sorts of grief. Likewise a poor 0V rail. If you can't have a gruound plane then a solid bit of wire is ideal. Make it grid of wire, round the edge of the board and connections across. The more solid the ground, the more predicatble the circuit.

If you don't have decent x10 probes then the DIY approach is a lenght of co-ax and a resistor. Terminae at the scope end with a T piece and a resistor the same impedance as the co-ax. At the other end of the probe put a resistor that's 100x the value of the termination. The voltage accuracy won't be brilliant and you'll need to crank up the gain of the scope but for logic neither of those usually matter. The extra loading on the circuit doesn't matter either in most cases. Don't forget to earth the braid to the circuit under test. A probe like this, even crudely made, is good to at least 1GHz. Far better than any x10 passive probe that I've seen and a lot more tolerant of long earth connection etc. And its cost is approximately zero.
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Re: The PMT in control of the Devil

Postby Harry Dalek » Thu Aug 17, 2017 11:31 pm

ppppenguin wrote:Just a thought. Do you have decoupling caps across the power pins of each chip? You really need 100n on each chip for HC. Inadequate decoupling can cause all sorts of grief. Likewise a poor 0V rail. If you can't have a gruound plane then a solid bit of wire is ideal. Make it grid of wire, round the edge of the board and connections across. The more solid the ground, the more predicatble the circuit.


Yes picture posted a page back but i will check just in case i missed the power rail and i hit another pin that could cause a problem mmmm but why it would effect the HC chip and not the the other any case i will check and report back .
The good ground idea is a good idea i will check and see if it can be improved i tend the use one side of the boards edge as the ground and the other side as the positive so the length of the board either side ,i do check the ground more than any thing .

If you don't have decent x10 probes then the DIY approach is a lenght of co-ax and a resistor.


Mine do have X10 switch i just didn't use it in this case seeing i should of i will keep that as some thing i will do next time .

Terminae at the scope end with a T piece and a resistor the same impedance as the co-ax. At the other end of the probe put a resistor that's 100x the value of the termination.


I have made a probe before but not to that standard

The voltage accuracy won't be brilliant and you'll need to crank up the gain of the scope but for logic neither of those usually matter. The extra loading on the circuit doesn't matter either in most cases. Don't forget to earth the braid to the circuit under test. A probe like this, even crudely made, is good to at least 1GHz. Far better than any x10 passive probe that I've seen and a lot more tolerant of long earth connection etc. And its cost is approximately zero.


Thanks for that jeff i had to make one and fix one around the time i started my 3bp1 monitor i ended up just buying 2 for my dual trace scope ..when you have a good one least you can check how accurate one made up is ...
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 PMT in control of the Devil

Postby Harry Dalek » Fri Aug 18, 2017 2:24 pm

OK i did learn a bit with todays work on the circuit ...first up i got the HC ic working correctly but only with a big change the the main PF capacitor from 44pf to 1533pf with a lot of trial and error testing capacitors with it ! and now works a treat ...using the trimmer to adjust pin 1 frequency 800hz its adjustable to mid range of the trimmer .
Below photos of the 4040 pin frequencies pretty much what is expected in Steves Schematic ...
I am please on 2 fronts that the circuit now works and my frequency meters are accurate enough...very much so on the gm328 not bad for a 15 dollar kit it out does my scope meter as you see its struggling at 100 khz i had to swap over to the GM328 kit meter for the rest of the higher frequencies .
I found BTW very correct on the frequency limit of the non HC 4046 ic's i tried to increase the frequency of the Non HC posted last post and i could not get it any higher it was pretty much working at its top range ,
Now thats sorted on to the next stages !
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INPUT pin 10 4040 out put 4046 3MHZ
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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 PMT in control of the Devil

Postby Harry Dalek » Fri Aug 18, 2017 3:29 pm

Happy to report Steve so far the Frame ramp generator works ..the line will have to wait till later test have to go out for a bit but looks very promising !!
:D

I just noticed i had a switch open the line ramp generator works as well here it is on the highest setting flipping the switch to the other positions every thing works ...thats nice no wiring mistakes ...now things get interesting ....Thanks to Steves circuit
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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 PMT in control of the Devil

Postby Steve Anderson » Fri Aug 18, 2017 6:12 pm

Progress indeed! Some of the scope traces look a little 'rough' but that could be down to the rather scattered layout of the project. Once it's tidied up a bit those may clean up.

I know I keep banging on about decoupling/bypassing and nice fat ground conductors or where possible ground planes, here you can see that it becomes essential when dealing with frequencies over 1000 times those usually found in NBTV circuits.

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Re: The PMT in control of the Devil

Postby Harry Dalek » Fri Aug 18, 2017 8:14 pm

Steve Anderson wrote:Progress indeed! Some of the scope traces look a little 'rough' but that could be down to the rather scattered layout of the project. Once it's tidied up a bit those may clean up.

I know I keep banging on about decoupling/bypassing and nice fat ground conductors or where possible ground planes, here you can see that it becomes essential when dealing with frequencies over 1000 times those usually found in NBTV circuits.

Steve A.


Yes its looking good Steve once i worked out the non HC 4046 was pretty much working at top frequency range i knew all the HC 4046 needed was dropping its frequency ,testing at the pin 1 800hz test point of the 4040 i just had to get that and all the other frequencies would fall in place ...
Any case looks good now .
I have put decoupling caps across the 6 ics..... no no i understand good to be reminded i will see i can add some more in different positions other ends of the ics shouldn't hurt .
Bit of cleaning up of the wiring i might next see how it works driving the The Thylacine .
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 PMT in control of the Devil

Postby Harry Dalek » Sat Aug 19, 2017 8:25 pm

Finishing off the circuit wiring to the case today and testing ...first up finishing off the decoupling capacitors one thing i did forget and added here was caps across the negative supply of the DAC chips .
Next working on covering and mounting the PMT in place nothing like a finished toilet roll and foil and duct tape ...needed to get the PMT in the focus area of the lens adjustable :wink:
Then wiring outputting the signals controls ...i can adjust the 4046 cock from pin 1 800hz test point plug ,it needs a slight adjusting on turn on ...i will show the frequency switching next post .
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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 PMT in control of the Devil

Postby Harry Dalek » Sat Aug 19, 2017 10:40 pm

Heres the frequency test 12 khz line frequency to 400 hz frame 12 to 50 hz .
So if i have it right line numbers with is can be ....this should be fun testing
On the 400hz 12 hz 25hz 50hz 33 line 16 line 8 line
800hz as above 66 32 16
1.6khz 133 64 32
3.2khz 266 128 64
6.4khz 533 256 128
12.8khz 1066 512 256

Bottom gif high line rate to low switching so 12.8khz to 400hz
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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 PMT in control of the Devil

Postby Harry Dalek » Sun Aug 20, 2017 11:25 am

BTW Steve i forgot to mention i looked into the PMT preamp i checked all connections and looked into then the parts used ..i didn't have a meter for the caps across the pin 2 and 6 of TL071 ic's i found checking one which i was thinking was 100pf ended up being 15.33NF i couldn;t check the 22pf but having a meter to double check i now have the right cap values in place and new TL071 ics in place ..i can check while working both input to the preamp and out put so once i get to that it should work better this time .
Next i am going to hook the saw tooth out of this to my monitor it should give better results than the scr sawtooth oscillators . if so can the PMT digital line and frame rate circuit be synced ? There are a few ways i can go from here hard wire it or make the video signal.
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 PMT in control of the Devil

Postby Harry Dalek » Sun Aug 20, 2017 6:27 pm

There are now a few paths to take on the signal to the monitor ...one path is what i am testing today and see how it works is to hard wire the pmt saw tooth oscillators direct to the Thylacine monitor V H deflecion circuits ....it works..... i would have more control over the size but the pmt case is screwed shut with the circuit for the ramp amplitude controls and i can see it works for to days test .
This sawtooth will be fed to the oscilloscope in time but no reason why it could not be fed to the monitor at the same time there would be no syncing problems .
Not putting all my eggs in the one basket doing it easier as above i would still like to make the video signals for the flying spot camera to feed to the monitor ,,bit harder but can't be any worse than doing it with a mechanical camera as i made a few month ago then again easier said than done i suppose .
i would think the lower line rates will be in the audio range so ok to upload the video signal for others to look at but the higher rates i would say i would just have the monitor and scope screens to show .
Advice welcome is all i can say when i get around to it !
The monitors screen display size is something to work on but nothing to stop it now displaying the flying spot video...so i will start thinking on and working on the ways i can go on the flying spot light side of it using the scope either a side projected side via the scope raster trace and my goal scope light projected off a subject .
the video circuit side needs to be made video driver for the crt may as well copy klass SSTV one should would here same sort of idea ...oh well getting the there .


youtu.be/wvE3Y0zCQF8
Testing 400hz to 12khz line rates and frame 12hz 25hz and 50hz rates
8 lines to 1000 lines
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disconnecting the Thylacine sawtooth oscillators and connecting the PMT circuits
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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 PMT in control of the Devil

Postby Harry Dalek » Thu Aug 24, 2017 3:29 pm

I have to work out how to make the compost video signal which is really multi system compost video signals ! and also having to do it the other way around for the monitor ,as i said a post of 2 back i can just hard wire the camera scanner idea right to the monitor cut out any syncing problems and circuits ..
But if possible i would like to try the harder way and make the video with horizontal and vertical sync pulses ,i will try and do this but any advice welcome here .
I am looking at it in a similar way to The PMT Nipkow camera i put together last year and using what worked there ..
I think the circuit below is Klass's club circuit and my changes that i used on the mechanical camera ,i think it would have the bandwidth the for all this but i am posting up here before i build just in case any one sees a problem with it .
Last time I was only adding horizontal sync to this circuit .... adding vertical to the same input point i should work again by adjusting its own pulse level ...
i am thinking to get the sync frequencies from the outputs of the saw tooth that will feed the oscilloscope the DAC pin2 feeding it to a monostable then adjusting its pulse width via the mono trimmer and sync level to circuit below 1 meg trimmer one for each of the sync V H pulses.
IF any thing it should work on the devil monitor at 32 64 range and be recordable .
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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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