My AC digital clocks run fast. Cheap fix?

[Peter]

I can't seem to get my local power company interested, but I suspect they are
the cause of the problem. I've got numerous AC powered digital clocks in VCRs,
DVRs, microwave ovens and clock-radios. The appliances are all made by
different manufacturers. Some were purchased this year and some are more than
10 years old. All run fast, several seconds/day. I have no problems with
brownouts, flickering lights, etc. I use only typical home appliances and most
of them were used in my previous homes (in other cities) where the older digital
clocks that are now running fast kept almost perfect time.

Doing a little research on the web, I found an article "Solving the Fast Clock
Problem" which can be viewed at this link:
http://www.writenowcommunication.com/PDF_Files/Solutns/Sol03.pdf

This article leads me to believe that my problem is external to my home. I do
not own an oscilloscope or any other sophisticated electrical analysis equipment
and I don't want to spend the money to hire an electrical engineer to assess the
quality of the power being supplied to my home. All the "power conditioners"
I've explored seem quite expensive.

Some of the clocks that are running fast are plugged into surge strips that have
EMI/RFI suppression built-in, so I doubt that an additonal EMI/RFI filter would
solve my problem.

Is there a simple, inexpensive solution to my problem or am I condemned to
resetting about 7 digital clocks each week if I want my wake up when I want to
and record TV programs when they are broadcast rather than before they start and
miss the endings?

 

[Bill]

The electric company is supposed to closely regulate the "60 cycles" so all
those clocks will keep perfect time.

Complain to your state agency which regulates your electric company. Might
also call a TV station or two and a newspaper. Before doing that, find other
people in your area who have the same problem...



"Peter" wrote in message

 

[Rich.]

I can't seem to get my local power company interested, but I suspect they
are the cause of the problem. I've got numerous AC powered digital clocks
in VCRs, DVRs, microwave ovens and clock-radios. The appliances are all
made by different manufacturers. Some were purchased this year and some
are more than 10 years old. All run fast, several seconds/day.

Although it is easy to blame the power company, I would have to say it is
not their fault or problem. The business of the power company is just that,
to supply you with power. Nothing within providing that service indicates
they're responsible to provide a clock timing pulse. This business of clocks
being accurate falls back to the manufactures. It's up to them to make a
product that works correctly. Instead of building an accurate clock, they've
taken the cheaper shortcut of trying to use the 60 Hz power line as the
timing circuit.

 

[Rich.]

The electric company is supposed to closely regulate the "60 cycles" so
all those clocks will keep perfect time.

The problem has nothing to do with the 60 Hz sine wave. This problem is
caused by additional spikes on the power lines.

 

[krw]

Although it is easy to blame the power company, I would have to say it is
not their fault or problem. The business of the power company is just that,
to supply you with power. Nothing within providing that service indicates
they're responsible to provide a clock timing pulse. This business of clocks
being accurate falls back to the manufactures. It's up to them to make a
product that works correctly. Instead of building an accurate clock, they've
taken the cheaper shortcut of trying to use the 60 Hz power line as the
timing circuit.

There are requirements for long-term (30-day) accuracy.

 

[Tzortzakakis Dimitrios]

Although it is easy to blame the power company, I would have to say it is
not their fault or problem. The business of the power company is just
that, to supply you with power. Nothing within providing that service
indicates they're responsible to provide a clock timing pulse. This
business of clocks being accurate falls back to the manufactures. It's up
to them to make a product that works correctly. Instead of building an
accurate clock, they've taken the cheaper shortcut of trying to use the 60
Hz power line as the timing circuit.

Here, in Crete, south Greece, the local control centre of the utility
(www.dei.gr) has a special display on the control room, that tells how
accurate a 50 Hz clock would be, had it followed the mains frequency. So.
yes, utilities care for those clocks, at least in Greece.

 

[James Sweet]

I can't seem to get my local power company interested, but I suspect
they are the cause of the problem. I've got numerous AC powered digital
clocks in VCRs, DVRs, microwave ovens and clock-radios. The appliances
are all made by different manufacturers. Some were purchased this year
and some are more than 10 years old. All run fast, several
seconds/day. I have no problems with brownouts, flickering lights,
etc. I use only typical home appliances and most of them were used in
my previous homes (in other cities) where the older digital clocks that
are now running fast kept almost perfect time.

Doing a little research on the web, I found an article "Solving the Fast
Clock Problem" which can be viewed at this link:
http://www.writenowcommunication.com/PDF_Files/Solutns/Sol03.pdf

This article leads me to believe that my problem is external to my
home. I do not own an oscilloscope or any other sophisticated
electrical analysis equipment and I don't want to spend the money to
hire an electrical engineer to assess the quality of the power being
supplied to my home. All the "power conditioners" I've explored seem
quite expensive.

Some of the clocks that are running fast are plugged into surge strips
that have EMI/RFI suppression built-in, so I doubt that an additonal
EMI/RFI filter would solve my problem.

Is there a simple, inexpensive solution to my problem or am I condemned
to resetting about 7 digital clocks each week if I want my wake up when
I want to and record TV programs when they are broadcast rather than
before they start and miss the endings?

The line frequency should have excellent long term accuracy. It may
drift a bit during the day but should catch up at night. If you're in
the US, I don't see how the frequency could be off since it's one big
interconnected grid. You might have noise on the line causing this. Can
you tell if the clocks drift steadily and in sync with one another or do
they sporadically skip?

 

[Peter]

The line frequency should have excellent long term accuracy. It may
drift a bit during the day but should catch up at night. If you're in
the US, I don't see how the frequency could be off since it's one big
interconnected grid. You might have noise on the line causing this. Can
you tell if the clocks drift steadily and in sync with one another or do
they sporadically skip?

They drift steadily. I haven't actually taken the time to precisely measure the
amount of drift that each clock has, but after a week, each is about 9-12
seconds fast. (My calibration standard is the time on both my "atomic" desk
clock and wrist watch, which are never more than an infinitesimal amount
different from each other.) It's a real pain for my VCRs and DVRs when we are
out of town for several weeks. Inevitably we end up missing the end of programs
we recorded near the end of our absence. Lately I've been adding 1-2 minutes to
the turn-off time to avoid that.

From the responses so far, sounds as though I'm going to have to live with this
issue until I move. I'll check with some of my neighbors to see if they have
noticed the same problem. However, I suspect from the random pattern with which
they collect their newspapers off their lawns that they may be less compulsive
than I am and not even be aware of the problem if they have it. If they have
cable or FIOS TV service (I don't bother) their VCRs and DVRs probably remain
accurate from the time signal I believe is transmitted with those services. (My
VCR was accurate until the analog to digital transition.)

 

[Archimedes' Lever]

I can't seem

Turn them off for a few seconds each day, troll.

 

[Peter]

Get a cheap electric clock that runs on a synchronous motor. See if when
it uses the power line frequency, which all these cheap clocks do, if
they have long term inaccuracy. Even quartz crystal clocks can be off.
Most new VCR synchronize off of PBS YV statops.

Bill

My stove's clock is an old fashioned synchronous motor clock. It keeps good
time. I suspect the problem is noise spikes, and probably not frequency
inaccuracy.

 

[Peter]

Do your neighbours experience the same problem? Does anyone a few
blocks away have it too? You might be on a bad spur that has a lot of
spikes or a source of interference connected to it.

And if they too have the same problem, I still don't have a solution. My
electric utility is ignoring me.

 

[Capt. Cave Man]

And if they too have the same problem, I still don't have a solution. My
electric utility is ignoring me.

Idiot. They would HAVE to have the same problem. Duh!

 

[Capt. Cave Man]

yet these spikes can still play havoc with the mains frequency
detector in clocks.

AC synchronous clocks do not have any such "detector".

The frequency IS what determines their operating speed.

 

[krw]

AC synchronous clocks do not have any such "detector".

Wrong again, WrongAgain.

The frequency IS what determines their operating speed.

And spikes at the crossings *can* fool them, DimBulb.

 

[Capt. Cave Man]

Wrong again, WrongAgain.

You're a goddamned retard.

They are defined by their physical construction.

No fucking detector.

And spikes at the crossings *can* fool them, DimBulb.

There is no detector, and waveform differences can tweak the assembly
faster for a given baseline frequency or slower.

 

[krw]

You're a goddamned retard.

They are defined by their physical construction.

A "synchronous clock" does not necessarily contain a synchronous
motor, AlwaysWrong. They can also be electronic, Dimmie.

There is no detector, and waveform differences can tweak the assembly
faster for a given baseline frequency or slower.

There often is a "zero crossing detector", AlwaysWrong. You can go
hide now, DimBulb.

 

[Capt. Cave Man]

There often is a "zero crossing detector", AlwaysWrong. You can go
hide now, DimBulb.

The only moving part is the rotor. The other "work" part is the coil.
There are NO electronics.

 

[Capt. Cave Man]

Wrong again, WrongAgain.

You're an idiot.

And spikes at the crossings *can* fool them, DimBulb.

Nope. At the zero crossing, and NOISE that you want to call a spike is
an order of magnitude smaller than the sine wave that is driving the
motor.

In other words... it is negligible. The coil and the rotor of the
motor are locked to the line frequency, and all but the most extreme
noise signature is not going to change the speed ANY significant amount
at all.

 

[James Sweet]

My stove's clock is an old fashioned synchronous motor clock. It keeps
good time. I suspect the problem is noise spikes, and probably not
frequency inaccuracy.

It could be something within your own home causing the noise. Switchmode
power supply with a bad input filter?

 

[Pieyed Piper]

Is there a simple, inexpensive solution to my problem or am I condemned to
resetting about 7 digital clocks each week if I want my wake up when I want to
and record TV programs when they are broadcast rather than before they start and
miss the endings?

Buy radio clocks. They update to the atomic clocks in Boulder.