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Adjustment


The adjustment, confirmation point of the digital clock that ended the assembly are shown below.

Confirm that output voltage is +12V by using tester etc.

Confirm with the part that combined the resistor( 470 ohm ) and the diode that are connecting in the battery circuit.
If the voltage of about 5V is out in the both ends of the resistor of 470 ohm it is OK. It assumed that it is charging the battery with about 10mA.
Until adjustment finishes a battery is removed. This is to do so that the battery does not discharge.
When all the adjustment finish and operate continuously the battery is inserted.

Do not forget the connection of the TV antenna.
Adjusting VR2 of frequency divider a television receiving station is selected.
It adjusts while hearing the voice of the television in the case that it is connecting a speaker.
Usually I am getting used to select the TV channel with push button, it is bothersome. I think with same even you.
The channel where it is able to receive is from 4 to about 8 probably( It depends on your country ). The broadcasting station that is able to receive it finely is selected.
There is the case that the picture is not can receive well even if the sound is heard normally.
It is the most reliable method to see the picture signal with the oscillo scope. I adjusted by using the oscillo scope.

The frequency counter is necessary to this adjustment.
First of all, the oscillation frequency of case that does not synchronize to the color burst signal of TV is adjusted. It is the oscillation by a crystal oscillator.
The oscillation frequency of 3.579545MHz and the frequency of 10MHz( Inclusion even the voltage adjustment of PLL synchronization ) is adjusted.
Frequency by this adjustment becomes the oscillation frequency of case that the picture signal of the television ceased, then adjust it as precisely as possible.
In this condition when you touch the crystal with your hand, you can find the change of the output frequency. ( Frequency changes by temperature )
Next, the picture signal of TV is connected. Even if you touch the crystal with your hand, the frequency does not change it is OK.
It is the condition which synchronized to the color burst signal from the broadcasting station.
Exact 10MHz was obtained with this.

Confirm the frequency of 50Hz of output.

Confirm the digital display.
When the power supply is turned on the display part is flashing.
When the LOW( Slowly renewal ) switch or UPR switch( Fast renewal ) are pushed the flash stops and time is displayed.
That the display color changes( red to green, green to red ) for every 12 hours is confirmed.
That second display LED of the center of the digital figure display changes every one second is confirmed.
That even the display color changes like the color change of the figure is confirmed.

That becomes a display 0 second when the second reset( LOW switch is pushed while pushing the SEC switch ) of the digital clock main board is done is confirmed.
That changes in 0 second from 59 seconds is confirmed.
The counting up in the second goes up and counts when second display LED of the digital clock main board was lighted.
That the minute display of the digital clock main board goes up and counts at the time of 0 second from 59 seconds is confirmed.

Inserting the battery it charges for a while.( About 10 minutes )
The clock is set in correct time.
If it passes about 10 minutes the AC power supply is turn off. The AC power supply is turn on once again several seconds later.
At this time, if the clock is operating in correct time the backup is OK.
If the time display flashes the backup is not normal. Check the battery circuit.

With the aforementioned adjustment and also confirmation the digital clock has come to display exact time.
Set the time and insert the battery, you put the clock in the clear position.
Time hangs to the charging of the battery. Because it charges automatically you do not need to worry about.