18th Jan 2019, 1:43 pm | #21 |
Dekatron
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Re: Turntable Stroboscope
65pF Vishay ones here for £2.44 + £1.38 p&p from a UK supplier:
https://www.ebay.co.uk/itm/Miniature...8YQQ:rk:7:pf:0 Hope that helps.
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18th Jan 2019, 1:54 pm | #22 |
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Re: Turntable Stroboscope
The circuit in the Product data sheet for the HEF4060BP shows a bias Resistor with the values 100 kΩ to 1 MΩ - should this be a variable Resistor?
No, the resistor is there to provide bias to get the input into a conductive region. Anything in the quoted range will do. |
18th Jan 2019, 8:26 pm | #24 | |
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Re: Turntable Stroboscope
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10th Feb 2019, 2:27 pm | #25 |
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Re: Turntable Stroboscope
After a somewhat lengthy diversion to build a Raspberry Pi Wireless Print Server, now deployed and working, I'm back to looking at the 300Hz strobe.
I carefully followed the design for a Typical crystal oscillator circuit shown in the HEF4060B Product data sheet (page 8) and wired up all the required components on a Breadboard - see attached picture. Couple of questions though: - 1. Will 4.5V be enough to get the whole thing oscillating? 2. How will I know that it is working at this stage before I go any further? Thanks in advance...
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10th Feb 2019, 3:05 pm | #26 |
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Re: Turntable Stroboscope
1 Yes.
2 All outputs will measure about half Vdd. |
10th Feb 2019, 3:25 pm | #27 |
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Re: Turntable Stroboscope
If you have a 'scope, logic probe or logic analyser you can check the the outputs are oscillating (the first and last will also let you check the frequency).
Or a piezo buzzer (the passive type, not the type with internal electronics) connected between the '300Hz' output and ground will buzz at, not surprisingly, 300Hz. Now I can't judge pitch at all but even I can tell if it's oscillating. |
10th Feb 2019, 5:01 pm | #28 |
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Re: Turntable Stroboscope
For a lower price than the trimmer you can buy an entire crystal oscillator set accurate to within 50 parts per million ( 0.005%) runs on 5v
https://uk.farnell.com/qantek-techno...lator%204.9152 David
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10th Feb 2019, 5:49 pm | #29 | ||
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Re: Turntable Stroboscope
Quote:
In addition the HEF4060BP started to run very hot - too hot to touch - so there may be something wrong with my Breadboard circuit connections?? Quote:
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10th Feb 2019, 6:01 pm | #30 |
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Re: Turntable Stroboscope
What have you done with pin 12 of the 4060? It should be connected to 0V (pin 8) I think.
You are not using the Topward generator to feed a signal _into_ the 4060 I trust. That could cause the IC to overheat or damage said IC. You want to just monitor the signals coming from the IC. |
10th Feb 2019, 6:27 pm | #31 |
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Re: Turntable Stroboscope
Pin 12 is connected to Pin 8 which goes to GND.
On the Topward I'm using the COUNTER IN connection with the FUNC/COUNT button pressed in which shows the input frequency.
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10th Feb 2019, 6:37 pm | #32 |
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Re: Turntable Stroboscope
OK, that sounds right for pin 12.
Does the IC still overheat if the Topward (counter) is not connected? You have the oscillator wired as in the datasheet. Pin 12 is grounded. You have a 4.5V battery between ground (pin 8) and pin 16. Are there any other connections to any pins of the IC? |
10th Feb 2019, 7:25 pm | #33 |
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Re: Turntable Stroboscope
I'll check for overheating with the Topward disconnected.
Pin 8 (Vss) and Pin 12 (MR) as detailed above Pin 10 (RTC oscillator pin) and Pin 11 (RS clock input/oscillator pin) as per datasheet. Connection from the battery to Pin 16 (Vdd)
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10th Feb 2019, 8:56 pm | #34 |
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Re: Turntable Stroboscope
It's a complete crystal and oscillator circuit in one package with an accuracy spec that encompasses the whole thing. Logic level outputs, so you power it from 5v and feed its output into pin 11 of the 4060. don't fir the rest of your oscillator circuit and leave pin 12 not connected to anything.
Excess heat in a CMOS logic part means something is either running at high frequency or is stuck between logic levels where the thing tries to operate in an analogue way and can waste current from the supply down through two transistors to ground. This makes heat. I'd suspect spurious oscillation of some sort. David
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10th Feb 2019, 9:09 pm | #35 |
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Re: Turntable Stroboscope
It's diffiicult to be sure, even in the enhanced photo of the breadboard below, but the oscillator components don't seem to be connected as per the circuit?
The resistor from pin 11 doesn't appear connected at the left hand end ? The crystal appears to be connected across the trimmer ? One end of the cap isn't connected at all? As for the overheating - the +ve and -ve rails are connected to the opposite labelled busbars. - Not a problem unless you connect the battery as per the labels. That would likely get the chip hot! Cheers |
11th Feb 2019, 11:39 am | #36 |
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Re: Turntable Stroboscope
Thanks Trigon - oh dear, it's back to the Remedial Class for me!!!!
I note that "The resistor from pin 11 doesn't appear connected at the left hand end" and "One end of the cap isn't connected at all" - I'm assuming that this is one and the same missing link on the Breadboard? "The crystal appears to be connected across the trimmer" - I'll look more closely at this but my understanding(!) is that only two tabs on the trimmer need to be connected - one of the outer tabs and the central tab? As for the +ve and -ve rails hopefully I've got that right where the red denotes the positive (+) terminal, and black denotes the negative (-) terminal on the battery. I changed this slightly and had the red (+) terminal going straight to Pin 16 (Vdd). Nothing else on the board needs power. The HEF4060B was running very hot so what are the chances it is fried?
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12th Feb 2019, 1:06 am | #37 | |||
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Re: Turntable Stroboscope
Quote:
Quote:
Quote:
Cheers |
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12th Feb 2019, 12:53 pm | #38 |
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Re: Turntable Stroboscope
Thanks again Trigon for taking the time and effort to provide such detailed responses - much appreciated.
Translating circuit diagrams to actual layouts and wiring connections (and vice versa) in various restoration projects was never my strong point! Probably just need more practice but that is sometimes difficult with this hobby which is quite often put on hold for long periods of time due to other priorities. What I think I'll do is take the old fashioned approach and use some coloured pencils to mock up my circuit on a paper Breadboard template. I can then Post that here for advice, guidance and entertainment!!!
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13th Feb 2019, 5:23 pm | #40 |
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Re: Turntable Stroboscope
If you search for 4060 in Google and select shopping there are loads. As you are running at 4.5V even the HC and HCT series will do.
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