Can I fix an inaccurate electronic clock?

November 4, 2017 at 22:47:19
Specs: several
I bought an 8" Philips Digital PhotoFrame in late 2014. One of
the very small number of features it includes is the ability to act
as a digital clock, and I use it that way. But it gains time at a
ridiculous rate. Something like 4 seconds per day. So it will be
a whole minute fast just 15 days after I set it accurately.

I've never in my life seen a timepiece that was so inaccurate,
including the first wristwatch my parents gave me back in the
1950's when I was maybe seven years old.

There are screws fastening the back to the display, so it is
conceiveable that I can at least look at the guts. But even if
I can get inside, is there any way I can adjust the clock?

-- Jeff, in Minneapolis


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#1
November 5, 2017 at 02:47:11
I wouldn't bother trying to fix it's timekeeping accuracy, electronic clocks don't have a regulator like traditional spring-driven clocks.

Just use it as a photo frame, buy yourself a "proper" digital clock if that's all you need it for.


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#2
November 5, 2017 at 10:33:19
I have seen some with a very small screw adjuster but mostly it's a matter of changing the crystal - assuming you can get one. Maybe cannibalize from some other clock and hope it's the same frequency.

You could try putting a small capacitor across the crystal but I don't hold out a lot of hope for that idea. If it slows then it's a matter of finding the right value capacitor which could prove tricky.

Always pop back and let us know the outcome - thanks


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#3
November 5, 2017 at 18:32:16
If the clock is synchronized to AC frequency (60Hz?) then it is "normal" to deviate.

The graph below shows possible sync errors on a 50Hz AC synced clock:
http://wwwhome.cs.utwente.nl/~ptdeb...


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#4
November 5, 2017 at 20:09:15
Derek wrote:

> I have seen some with a very small screw adjuster

That's enough to get me to open it up and look, though I
very much doubt it has any such affordance.

> but mostly it's a matter of changing the crystal - assuming
> you can get one. Maybe cannibalize from some other clock
> and hope it's the same frequency.

That's an interesting idea! Sounds like it would involve an
almost microscopic soldering job, though. Extremely easy
for me to catastrophically screw up.

sluc wrote:

> If the clock is synchronized to AC frequency (60Hz?) then
> it is "normal" to deviate.

In the thread title maybe I should have described the clock
as "digital" rather than "electronic". It is powered by AC via a
(very small) wall brick, so I'm sure it runs on DC, the same as
a wristwatch or computer clock (which is a major reason I
chose to post here). So no AC synchronized motor. If there
are clocks synchronized to the AC power supply by some
method other than AC motor, I'm interested to learn more.

-- Jeff, in Minneapolis


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#5
November 6, 2017 at 07:26:26
I was assuming digital. [I've never known directly A.C. driven clocks to gain for the obvious reasons. Losing or stopping due to sticky rotor bearings can happen though].

I used to repair mechanical watches and clocks as a source of extra income in my younger days when my pay was low. I only repair my own watches these days - having stopped some years ago I lost a fair bit of confidence in dealing with small stuff, such as ladies mechanical watches.

Always pop back and let us know the outcome - thanks


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#6
November 10, 2017 at 09:23:12
You ask some of the oddest questions. Buy a new clock!

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#7
November 10, 2017 at 10:22:20
I don't need a new clock. I already have another one that isn't
being used. :-p

-- Jeff, in Minneapolis


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#8
November 14, 2017 at 05:04:48
I opened the digital picture frame. Curiously, the "frame" part
of it is identical to an ordinary picture frame. Wood and glass.
A surprisingly large number of individual components besides
the three large ICs. I didn't try to identify them. No obvious
clock IC. Two crystals on the underside of the PC board, in
silver cannisters of different size and shape. As expected,
nothing that could be adjusted.

Maybe if I put it outside, the cold would slow it down....

-- Jeff, in Minneapolis


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#9
November 14, 2017 at 07:15:00
"Maybe if I put it outside, the cold would slow it down"
or speed it up maybe - reduced crystal size faster vibrations

Always pop back and let us know the outcome - thanks

message edited by Derek


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#10
November 14, 2017 at 09:36:55
Derek,

I had no idea, and it is such an easy thing to understand,
it would make a great bit in a science fiction story.

Since I'm in an apartment building, and no longer in a unit
with a balcony, I really can't stick anything out the window.
I need to test it with a smaller timepiece in the refrigerator
or freezer. I have a brand-new digital stopwatch....

-- Jeff, in Minneapolis


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