The PMT in control of the Devil

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Re: The PMT in control of the Devil

Postby Harry Dalek » Sat Jul 29, 2017 3:18 pm

OK pretty much finished the wiring now i am not sure Steve if there's another chip or two to it ? but i am up todate now with the circuit i think i can fit something else on the board if need be .
Boards been used on one side twice before cleaned it up best i could and 3rd time lucky here .
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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 » Sat Jul 29, 2017 6:33 pm

When you do get the correct chips, don't plug them in all at once, start at the beginning, sort out the oscillator, then move on to the downstream stuff. Slowly, slowly, catchee monkey.

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Re: The PMT in control of the Devil

Postby Harry Dalek » Sat Jul 29, 2017 7:51 pm

Steve Anderson wrote:When you do get the correct chips, don't plug them in all at once, start at the beginning, sort out the oscillator, then move on to the downstream stuff. Slowly, slowly, catchee monkey.

Steve A.


No worries will do i will have to put this a side till they do turn up ,which i hope is next week .
bit on a 1964 flying spot scanner in the PDF for those interested /
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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 » Wed Aug 16, 2017 4:52 pm

All my ic's turned up this week so i am keen to see this working .
I am scratching my head as i am no where near the frequency numbers in the circuit i am pretty close to the input frequency i think looking at my new meter but whats coming out of the 4040 HC looks very wrong ! where i could i double checked with the limits on my little scope meter but looks like its not the meter.
The test output at pin 4 4046 first photo showing frequency here ...and on pin 1 output 4040 6.6khz same on both meters ...and other readings i took i put on your Schematic Steve.
The frequency control on the 4046 is very tight its doable but i think i will replace with a multi turn trimmer and it does drift a little bit you have to tweak it on power on its understandable at 3mhz....its some thing like 3278 to 3400 if i have turned it off and back on again .
Any case i have gone wrong somewhere here ...my new meter also does capacitor readings so the 47pf i put in for the 4046 is reading a touch lower at 44pf.
EDIT
looking at my readings next to yours Steve there a re a few that are close to those frequencies s but not on the same pin positions .
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Last edited by Harry Dalek on Wed Aug 16, 2017 6:18 pm, edited 2 times 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 » Wed Aug 16, 2017 5:48 pm

The oscillator in any 4046 or HC4046 is NOT a precision device. You certainly don't want to rely on it being stable outside a phase locked loop. It will drift sginificantly with time and temperature.

At 3MHz it should be fairly predictable but there will be signficant differences between different manufacturers and even between different parts from the same maker. For a 1 off amateur project it doesn't matter if you have to AOT component values.
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Re: The PMT in control of the Devil

Postby Harry Dalek » Wed Aug 16, 2017 6:11 pm

ppppenguin wrote:The oscillator in any 4046 or HC4046 is NOT a precision device. You certainly don't want to rely on it being stable outside a phase locked loop. It will drift sginificantly with time and temperature.

At 3MHz it should be fairly predictable but there will be signficant differences between different manufacturers and even between different parts from the same maker. For a 1 off amateur project it doesn't matter if you have to AOT component values.


Yes Jeff i would not expect the 4046 to be like a crystal oscillator thats fine with me just letting Steve Know when he see's this what i am seeing .
Funny enough i tested 8 out the ten i just got and at the pin 1 4040 test point ....and 7 of them i was getting the 6khz reading and 1 i got 4 khz !
The slight drift at the 4046 is only a minor thing ...the big difference as to what was expected out of the 4040 doe's have me wondering .
Last edited by Harry Dalek on Wed Aug 16, 2017 6:29 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 PMT in control of the Devil

Postby Steve Anderson » Wed Aug 16, 2017 6:19 pm

Wow! What's going on here? As ppppenquin mentioned these oscillators are not precision devices, I did say you'd probably have to fiddle around with some of the component values. But whatever is currently coming out of the 4046 make a note of it in frequency terms. Then go down the 'ladder' of outputs on the 4040 and each should be half of the previous. I have double-checked I got the correct pins on the 4040 against the Philips datasheet.

If they aren't my next move would be to fire up one of your 'real' oscilloscopes, OK they don't have a frequency readout but they should easily cover up to 10MHz. Measure the period (rising edge-to-rising edge) in us/ns of the waveform at the 4040 pin 10. First, is it stable? If yes then go down the 'ladder' of the 4040 and ensure that each output is twice the time (half the frequency) of the previous...ensuring they are rock-solid stable too, and a 50% duty-cycle, equal high and low time.

Without a specification for the little LCD scope I'm wondering if it can cope with these frequencies, it may only be good to upper audio frequencies even though it may display the waveform correctly(?).

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Re: The PMT in control of the Devil

Postby ppppenguin » Wed Aug 16, 2017 7:11 pm

When Steve and I say that the 4046 oscillator isn't a precision device we're guilty of understatement. There's no way I'd be using one free running 9as against phaselocked) unless I could tolerate perhaps 20% or even greater frequency error. For a better RC oscillator a HC14 schmitt trigger in a simple relaxation oscillator circuit will be a lot more stable. Obviously LC would be better and xtal better still. All are possible using simple HC gates and handful of passives.

As for the divider chain, Steve is 100% correct. Get a 'scope on it. Many problems become very obvious that way. A frequency counter is all well and good but you don't know if it's mistriggering on overshoots or failing to trigger on some transitions. I've been fooled in the past which is why I rarely use a counter. If the scope's calibration isn't good enough I usually measure frequency by putting the output of a synthesised signal generator on another scope trace and adjusting for minimum slip. That may not be an option for most people. Once you know the waveforms are OK then you can use a counter to check the frequency exactly.
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Re: The PMT in control of the Devil

Postby Steve Anderson » Wed Aug 16, 2017 7:33 pm

The 4046 was a start, as ppppenquin mentioned they're atrocious devices in terms of long-term stability and sensitivity to supply voltage. Once this divider error is sorted perhaps we could look at an alternative device or phase-lock this to something more stable - but that without getting more complex removes the ability to alter the frequency over a small amount, say +/-10%.

So perhaps a simple gate plus an RC oscillator is all that's required.

Why I suggested using a 'real' analogue scope is it removes the possibility of aliasing which these simpler digital scopes my be suffering from.

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Re: The PMT in control of the Devil

Postby Harry Dalek » Wed Aug 16, 2017 7:44 pm

Steve Anderson wrote:Wow! What's going on here? As ppppenquin mentioned these oscillators are not precision devices, I did say you'd probably have to fiddle around with some of the component values.


Thats no problem Steve fiddling with it due to the components used on the 4046 i would think the frequency is close .

But whatever is currently coming out of the 4046 make a note of it in frequency terms. Then go down the 'ladder' of outputs on the 4040 and each should be half of the previous. I have double-checked I got the correct pins on the 4040 against the Philips datasheet.


I will double check the philips against this one should be copies pin wise but never know .

If they aren't my next move would be to fire up one of your 'real' oscilloscopes, OK they don't have a frequency readout but they should easily cover up to 10MHz. Measure the period (rising edge-to-rising edge) in us/ns of the waveform at the 4040 pin 10. First, is it stable? If yes then go down the 'ladder' of the 4040 and ensure that each output is twice the time (half the frequency) of the previous...ensuring they are rock-solid stable too, and a 50% duty-cycle, equal high and low time.



OK thats some thing i can try some of the pin outputs of the 4040 are out of range of this little scope ...i could only check via the new Gm328 meter .


Without a specification for the little LCD scope I'm wondering if it can cope with these frequencies, it may only be good to upper audio frequencies even though it may display the waveform correctly(?).

Steve A.


Well i did check it against my scope frequency meter and seemed accurate ...The GM runs on a 8 Mhz crystal so i would think it can do testing at a few MHZ...playing with it its amazing how much it can do .
http://www.ebay.com/itm/DIY-GM328-Trans ... 2320389743
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Re: The PMT in control of the Devil

Postby Steve Anderson » Wed Aug 16, 2017 8:12 pm

The last couple of stages (6.6 & 13.2kHz) seem plausible, but above that it seems almost random. I still strongly suggest getting a 'real' scope on this first, we'll attack the actual frequencies later.

I had a look at the ebay pages, there's no mention anywhere of its performance or limits. It appears to be a transistor tester first and the frequency meter/scope is a bolt-on goodie. After all they illustrate it showing 5000Hz, not in the 100s of kHz or MHz.

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Re: The PMT in control of the Devil

Postby ppppenguin » Wed Aug 16, 2017 8:46 pm

A scope is essential for anything beyond the most basic design work. Obviously not everyone needs an all singing all dancing instrument but a simple dual trace 20MHz analogue scope can do a lot of work. In the UK there's a good choice of secondhand instruments for under £50. Hameg scopes are solid and reliable in that price range. Probably more so than Tektronix. Digital scopes have improved a lot. I have a Rigol DS1054 which was about £250 new and it will do everything you could possibly want for SD and NB TV. I still love my pure analogue 400MHz Tek 2465B - you'd have to prise it out of my cold, dead hands. But that's way more than you'd need here.

I'm very tempted by the Analog Discovery 2 USB based test set that my friend Nick has bought:
http://store.digilentinc.com/analog-dis ... er-supply/
http://golbornevintageradio.co.uk/forum ... p?tid=6222
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Re: The PMT in control of the Devil

Postby Harry Dalek » Wed Aug 16, 2017 9:03 pm

ppppenguin wrote:A scope is essential for anything beyond the most basic design work. Obviously not everyone needs an all singing all dancing instrument but a simple dual trace 20MHz analogue scope can do a lot of work. In the UK there's a good choice of secondhand instruments for under £50. Hameg scopes are solid and reliable in that price range. Probably more so than Tektronix. Digital scopes have improved a lot. I have a Rigol DS1054 which was about £250 new and it will do everything you could possibly want for SD and NB TV. I still love my pure analogue 400MHz Tek 2465B - you'd have to prise it out of my cold, dead hands. But that's way more than you'd need here.


That would be nice Jeff i have a few old scopes one from the 60s 70's 80s its been winter here so my scopes are in the shed where i do my work in the warmer months ,i have a little corner of the house a desk where i do my winter work like now ..
I can't with a family spend to much on the hobby as you can understand so i make do on the cheap very cheap :roll:
I see your point on the scopes no ones getting mine you are blind with out them , nothing like a scope waveform showing the thing really works i understand...with higher tv line rates my little scope i use for NBTV is not up to the job have to give it a rest in parts of this one .


Steve Anderson wrote:The last couple of stages (6.6 & 13.2kHz) seem plausible, but above that it seems almost random. I still strongly suggest getting a 'real' scope on this first, we'll attack the actual frequencies later.

Yes i was studying the doubling halving it does go strange ,i will get it out on the old scope and look ..

I had a look at the ebay pages, there's no mention anywhere of its performance or limits. It appears to be a transistor tester first and the frequency meter/scope is a bolt-on goodie. After all they illustrate it showing 5000Hz, not in the 100s of kHz or MHz.


Steve A.
[/quote]

What i saw searching was gos to 2 mHz or more what ever that meanings these Chinese kits always have poor translations ..seems to display up to 3Mhz ,have to make a crystal oscillator hook it up then i will know for sure know the crystal you know what the results should be.

Yes i will hook it up to the old scope and see tomorrow

Now i tracked down the philips data and my texas instruments version i think theres a problem if the pins Q letters equal the Q numbers of the other version ... at the 5th count divide they are different ?
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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 ppppenguin » Thu Aug 17, 2017 1:37 am

The ABC/123 pin equivalents looks fine to me.

Another data sheet: https://assets.nexperia.com/documents/d ... CT4040.pdf
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Re: The PMT in control of the Devil

Postby Harry Dalek » Thu Aug 17, 2017 12:57 pm

ppppenguin wrote:The ABC/123 pin equivalents looks fine to me.

Another data sheet: https://assets.nexperia.com/documents/d ... CT4040.pdf


Yes my mistake looking at it again jeff .....
i checked the frequencies on the scope apart from a bit of distortion on the higher frequencies it looks correct...
The frequencies out of the pins i am confused about as both my meters on the lower frequencies they both can work at are showing same readings so i can't say ones off which one works ..its unlikly.... where the frequencies go beyond my scope frequency meter and i just have the GM328 kit meter i will have to use a known crystal and make a oscillator and check its limits and how accurate it is .
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