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SC8560 AM/FM clock radio 50Hz drifts

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Greetings Audioguru!

In our Country illegal connections from Grid are a way of life, many times the Grid supply gets tripped b'coz of heavy industries resorting to Power pilferage.

recently the Main Grid stopped the supply b,coz the Freq. fell to 48.5 Hz.

the economics of Demand and supply come into picture here.
 
nura100 said:
In our Country illegal connections from Grid are a way of life
You live in a crazy country without any laws, police or morals.

the economics of Demand and supply come into picture here.
Here, if somebody wants something they buy it, not steal it.
 
audioguru said:
You live in a crazy country without any laws, police or morals.


Here, if somebody wants something they buy it, not steal it.

What, you mean there's zero crime in Canada?, what are all those mounties in the funny hats doing then?.
 
The Royal Canadian Mounted Police are for display. I think they were appointed by your queen.
They don't chase American criminals who sneak across the border. Their vicious dogs chase the criminals while these guys watch.:D
 

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You can also try to get hold of a 3,276,800 Hz crystal that will give you 50 Hz as well by dividing it by 16.
That one is more common and you should be able to source one of those with a bit of luck.
Jaycar sells it cat nr RQ-5271 for NZ$ 3.95 (US$ 2.60)

Good luck and let us know if you succeed.

edited for typo's RF.
 
RODALCO said:
You can also try to get hold of a 3,276,800 Hz crystal that will give you 50 Hz as well by dividing it by 16.
I've already suggested that and you mean [latex]2^{16}=65536[/latex] not 16.

Craplin sells them specifically for this purpose.

**broken link removed**
 
Also 4.9152MHz crystal can easilly give you 60Hz.

[latex]60 = \frac{4.9142 \times 10^6}{10 \times 2^{13}}[/latex]
 
Thanks for the correction, you are correct (2 to the power of 16) Hero999 i didn't see your post or must have read over it.
my mistake.
(Can't get the 16 up the higher level)

Cheers
RF.
 
Dear All,
Thanks for all your posts.

Atlast, I thought i will go will using two IC's and leave the idea to generate line frequency with a single IC.
So i am using CD4060 and CD4018. I have 2.4579Mhz crystal that is divided to 600Hz using CD4060 and then divide by 10 using 4018.
I am facing following troubles.

1. The 600Hz output at CD4060 pin 1 i.e Q12 does not come up immediately on power on. Most of the times, its take 20 sec for the wave form to come up. This is wierd, i have rewired the board 3 to 4 times, but the same problem.

2. How do i interface this in the radio ? It has a SC8560 that apparently works on negative voltage. Can i just swap the + and - points i.e Vdd and VSs for 8560 and CD4060 or do i need to take any other steps ? I have never done this kind of connections !!!
 
manoj.patil.1974 said:
Dear All,
Thanks for all your posts.

-----------------------

1. The 600Hz output at CD4060 pin 1 i.e Q12 does not come up immediately on power on. Most of the times, its take 20 sec for the wave form to come up. This is wierd, i have rewired the board 3 to 4 times, but the same problem.

2. How do i interface this in the radio ? It has a SC8560 that apparently works on negative voltage. Can i just swap the + and - points i.e Vdd and VSs for 8560 and CD4060 or do i need to take any other steps ? I have never done this kind of connections !!!

Hi Manoj,

1. Check reset capacitors any pull up resistors - for possible defects. otherwise 4060 never took seconds for output when we tried.
next you always depend on this clock source whether power is ON or OFF. thus no further worry.

2. reg polarity-- keep your child card isolated and connect to the relevent voltage- and if trsition to high or low is of importance, you may invert it ( i don't think it really matters. )
 
Attach the schematic of the malfunctioning CD4060 circuit including its power supply voltage.

The CD4060 has a binary counter. It divides by 512, not 600.
 
Hello,
Pls note that i did not mean divide by 600. I am using CD4060 to divide the crystal frequency of 2.45760 by 4096 i.e 2 power 12 available at pin Q12.
I will try to explain the schematic right here as its very simple ( as i dont have a diagram that i can upload right away, will try to figure out soon on how to do that)
The crystal pins are connected directly to pin 10 and pin 11. Each crystal pin is also grounded via 33PF capacitor. Pin 9 is left open ( may be this is a mistake, but datasheets dont mention anything about this)
Pin 12 i.e Reset is connected to a Capacitor (10mfd) & resistor 10K. Rest all other pins are left open.

I have tried this atleast 100 times and the waveform appears about 20 sec delayed.

However, i am facing a new and a larger problem. I get the 600Hz waveform neatly and then it gets divided by 10 using the decade counter 4018.

However, when i connect this 60Hz waveform to the SC8560 60Hz line frequency input, the LED displays goes in a hang state and none of the time setting or alarm switches function too.. everything just freezes...

I have tried to use the Zelscope shareware software which is a PC based oscillosope that uses the sound card for ADC. The 600Hz waveform shows up neatly in the time and freqency domain. However, the 60Hz shows up as 64.60Hz (not sure if this is due to software error or the probe problem)....

As of now, i have kept the whole thing connected for 2 hrs and the LED display still shows a frozen 1P:G8 code.... any ideas whats the solution ???

I even tried to add a BC547 at the output of 4018 (Q5) and then connect the collector to Pin25 of 8560.. but no use... !!!!!
 
The CD4060 crystal oscillator needs a high value resistor (1M to 10M) in parallel with the crystal to bias its oscillator inverter as a linear amplifier.

The supply voltage of the CD4060 crystal oscillator and CD4018 divider must be the same as the clock iC.
 
It would help us if you post a circuit of your counter and the relevant part of the clock circuit.

If you have paper copies you can either scan or photograph them.

Alternatively, you can draw them in Paint, PowerPoint, etc. and convert to a .gif before uploading.
 
manoj.patil.1974 said:
The crystal pins are connected directly to pin 10 and pin 11.
Correct, but did you connect the resistor suggested by Audio?
manoj.patil.1974 said:
Each crystal pin is also grounded via 33PF capacitor.
Correct although 33 pF may be a bit high
manoj.patil.1974 said:
Pin 9 is left open ( may be this is a mistake, but datasheets dont mention anything about this)
Correct. If you connect a scope or frequency meter to this pin you should read the oscillator frequency.
manoj.patil.1974 said:
Pin 12 i.e Reset is connected to a Capacitor (10mfd) & resistor 10K. Rest all other pins are left open.
You don't need to reset the counter in this case. As you are using it as a frequency divider, it does not matter what initial state it goes into at power on. Connect pin 12 to gnd (assuming that pin 8 is connected to gnd).

All other pins must be left open
 
Forum ! Hi,
Bingo !! A 4.7Mohm across the crystal did the trick and the CD4060 oscillates immediately on power on !!!

However, my larger problem persists. I have connected the CD4060 and CD4018 for power from the SC8560 power supply itself. But, when i connect the 60Hz output of CD4018 to SC8560, it goes into a flickering on LED as if its counting at a very high speed.
I tried using a AC coupling ( 1ufd polyster) capacitor, but that does not help...
Hmm.. i am short of any clues ? can u pls help !!!
 
Good, you made the oscillator the same as is shown in the datasheet.

Does the new counter circuit use the same power supply voltage as the clock IC and are both 0V lines connected together?
 
Have you connected 100nF decoupling capacitors across the supply to each IC?
 
-- CD4060, CD4018 Vss pins connected together. This is then connected to the Vdd i.e Pin 20 of SC8560
-- CD4060, CD4018 Vdd pins connected together. This is then connected to the Vss i.e Pin 15 of SC8560.
-- I have connected a common 33Pf capacitor across the Vdd and Vss power supply connector for the CD4060 and CD4018. ( I dont have a 100nf capacitor right now, its night here, will buy it tomorrow and try out that too)

-- 1 microfarad AC coupling capacitor does not help.
-- I tried to create a low pass filter. Capacitor (1 microfarad) grounded, another pin goes to resistor ( 10K, 4.7K, 50K, 330K, 1Mohms) connected to Vdd. The common point goes to the 60Hz input of SC8560. This does not help for all the values of resistors

Huh !!!!

Looks like the harmonics frequencies in the square wave are troubling the 60Hz input block of SC8560. Looks like the schmidt trigger in there is being fooled by something spurious. How do i block that ? Creating a band pass filter that would allow only 60Hz out is very difficult ( I have limited tools here)... I am thinking to use a optoisolator... would that help to filter out those harmonics or any spurious data generated by CD4000 series ???
 
An RC filter will probably do.

What trigger level do you need?
 
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