This is NOT an isolated incident. This is a brand new unit. In fact it
is the EIGHTH unit with this problem. I have two of them(both brand
new) set up next to each other and BOTH are doing the same thing. The
others had the problem with most with worst time problems. The first 5
were from Walmart. Well, they don't carry it anymore. The next 3 were
from Sears and now they are out of them. I didn't buy them all at the
same time. I just kept exchanging them. It was about the 4th or 5th
one before I started tracking the date codes and have had a wide
variety of codes.
Any ideas on a fix?
GE, and a few others have some models that get their time from the NIST.
This means that you just have to set it close for the time, and after 24
hours, it would keep itself adjusted as long as it can get the signal. Just
make sure it is set for the proper time zone to start with. I have a few of
these clocks around our home, and they never go off time!
--
Jerry G.
==========================
"Rusty" <ru...@rusty.com> wrote in message
news:mct5i05qlcvt0hof0...@4ax.com...
If they all are the same model, then I agree, it's junk.
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And do you have some unusual kind of noise on the power lines?
See if they keep time correctly in your office, or in someone else's home.
>I recently bought the RCA RP3710A Alarm Clock radio. The problem with
>it is that it randomly gains time. Never loses time. What I mean is
>that it might run fine for 15 hours with the time right on to the
>second and then boom, it gains a random amount of time. It might only
>be 1 hour or 24+ hours before it happens. Today it kept the right time
>for about 6 hours and then it gained 4 minutes. Then for the next 8
>hours it kept that 4 minute difference and checking it just now, it
>gained another 2 minutes.
>
>snip
I have a Magnavox clock radio with battery backup. Every time I lose
power to the house, the clock radio gains between 3-5 minutes. I don't
know if this info helps at all.
That is extremely relevant. Do his problems coincide with brief power
outages?
I know some replies said junk, try another model and such. That is not
the key here. I am curious as hell and am trying to figure it out.
Now if I could find the schematics for this I would be set.
On 18 Aug 2004 08:30:22 -0400, Sam Goldwasser <s...@saul.cis.upenn.edu>
wrote:
Is the clock reacting to the offpeak switching signals from your
electricity supplier?
- Franc Zabkar
--
Please remove one 's' from my address when replying by email.
>I recently bought the RCA RP3710A Alarm Clock radio. The problem with
>it is that it randomly gains time.
Which chip does it use? Maybe the application circuit in the datasheet
will tell us something.
>I recently bought the RCA RP3710A Alarm Clock radio. The problem with
>it is that it randomly gains time. Never loses time.
Apparently you're not the only one with this problem:
http://electronics.kewler.net/rca-rp3710-amfm-clock-radio-with-09-backlit-lcd-digital-tune-dual-wake_B00008UVAG_i.html
> Only this model clock radio. No other clocks of any sort in the house
> is affected in this way.
So, out of curiosity, if you have been having problems with this model,
why have you puchased 8 of them? :)
The topic of the thread was remote-reading electrical power meters - you
could Google it. The gist of the topic was that there are many ways in
which a remote-reading power meter can work. Most cause no harm or
interference of any kind. But one of them involves "modulating the
zero-crossings" in the AC waveform, a signalling method which can be
triggered and read from a remote location. Apparently, this technique
can cause extra zero-crossings to show up, and a clock which counts time
by counting zero-crossings will gain time. There is any easy fix, IIRC.
So the question becomes, has the power company retrofitted the power
meters in your neighborhood recently?
Bill
I'm glad my semi-antique (30+ years) clock radio still uses a synchronouc
motor. Full cycles are all that matter! :)
How did a signally scheme like that ever get approved? A large precentage
of AC powered clocks must count zero crossings.
But, didn't he say he thought there was a crystal in the RCA?
> Bill Jeffrey writes:
>>The topic of the thread was remote-reading electrical power meters -
>>you could Google it. The gist of the topic was that there are many
>>ways in which a remote-reading power meter can work. Most cause no
>>harm or interference of any kind. But one of them involves
>>"modulating the zero-crossings" in the AC waveform, a signalling
>>method which can be triggered and read from a remote location.
>>Apparently, this technique can cause extra zero-crossings to show up,
>>and a clock which counts time by counting zero-crossings will gain
>>time. There is an easy fix, IIRC.
>>
>>So the question becomes, has the power company retrofitted the power
>>meters in your neighborhood recently?
> I'm glad my semi-antique (30+ years) clock radio still uses a synchronouc
> motor. Full cycles are all that matter! :)
Yup. But they are gettign harder to find. Electronics is cheep!
> How did a signally scheme like that ever get approved? A large precentage
> of AC powered clocks must count zero crossings.
Actually, the post that I read may have been referring to the signalling
scheme used by the X-10 products - a short burst of 120KHz at the zero
crossing. IIRC, the "easy fix" was to add a 0.001 cap across the clock
circuit, which would probably reduce the level of 120 KHz to an
insignificant level. Haven't yet found the post I am referring to, but
there wasn't much more than that.
> But, didn't he say he thought there was a crystal in the RCA?
Yes, he did. I assume that the crystal oscillator is there simply to
take over in the event of power failure. For "normal" operation, the
power line frequency (or at least aggregate number of cycles over 24
hours) is much more accurate than any cheap crystal oscillator.
So the next question for the OP is, have you recently installed any X-10
equipment?
Bill
>Sam Goldwasser wrote:
>> But, didn't he say he thought there was a crystal in the RCA?
>
>Yes, he did. I assume that the crystal oscillator is there simply to
>take over in the event of power failure. For "normal" operation, the
>power line frequency (or at least aggregate number of cycles over 24
>hours) is much more accurate than any cheap crystal oscillator.
I suspect the crystal also provides the clocking for the uP (?) and
LCD. AFAIK, a uP can't get much work done at 50 or 60Hz :-)
Thanks
>>>This is NOT an isolated incident. This is a brand new unit. In fact it
>>>is the EIGHTH unit with this problem. I have two of them(both brand
>>>new) set up next to each other and BOTH are doing the same thing.
Do they both do it at the same time?
If so, my guess is that there is some noise on your line occasionally
which fools the clocks into counting them as extra cycles. It might be
possible to add a filter to the input that would only pass thru
frequencies near 60 Hz, but I'm afraid that such a filter would
probably be rather large.
-
-----------------------------------------------
Jim Adney jad...@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------
also some devices has a hz selector on the back make sure it is set to
the proper setting.
In article <mct5i05qlcvt0hof0...@4ax.com>, Rusty
Take it back for exchange.
N