There's actually a bit of story attached to this fridge. I just checked
and it turns out it's almost 7 years old - so well over 50000 hours on
the display. It displays the setpoint except for a little while after
you change the temperature it will display the current temperature. It's
been sitting with "4" and "38" all its life.

I remember walking into the kitchen at night and the blue glow was
pretty strong. Now the display is still readable with the room lights on
but looks real dim.

When we got this fridge I decided to replace the ice water line and
filter, so it was a week or so without the icemaker. After hooking up
the water I started noticing the fridge was running all the time. And
the freezer was really cold - you couldn't spoon ice cream. No change in
the freezer settings made any difference. I put a dual thermometer in
the two compartments and the freezer was running -26 F. Yes, minus 26.

To make a long story short, I think the icemaker is a little undersized,
so it's programmed to run the freezer full tilt unless the ice drawer is
full.

I called for warranty service and the repairman came out and told me he
would go through the paces and replace the temp sensor and motherboard
but it wouldn't fix it, and he'd call me in a couple of weeks when the
parts arrived. He never called me and after a month of me phoning it
seemed like nothing was going to happen, so I called Samsung and asked
for another repairman.

A week later there's a voicemail "this is Samsung in New Jersey and we
need your authorization to send you a refund check". I call back and
they say there's no other repair center nearby and so they are refunding
the full price of the fridge. I ask how to return the old fridge and
they say, "no, disposing of it is your problem, but you must peel off
the serial number sticker, cut off the power cord and send them to us".
What should I do for a fridge between no power cord and money for new
fridge? "splice a new cord on and keep using the old fridge, we don't
care."

I do the deed and get a check and think about a new fridge. But wait,
when we bought this fridge, my wife and I walked around and looked at a
hundred fridges until she stood in front of the only one that was
acceptable. So I didn't want to try to find another acceptable fridge.

But I had a check for $900. They basically paid me to fix an embedded
system. So I fixed it, and my fridge got a PIC16F876 to control the
icemaker.

It intercepts the ice tray thermistor, icemaker full switch, reads the
state of the display and controls the icemaker itself. I put a serial
bootloader in it so programming it was easy, and it sends debugging info
out also. When I did the work I didn't bother to note the resistor
values in the display driver, so I don't know how much current it's
getting.

A new control panel with display is about $45. I may buy a new one but
probably not. Seven years is probably the design life of the fridge,
I'll practice "benign neglect" and hopefully get another seven years out
of it.

Bob

On Fri, Jul 4, 2014, at 03:37 PM, Marcel Duchamp wrote:
> Curiouser and curiouser...
>=20
> Very interesting data, Bob.  Things that popped into my addled brain are:
>=20
> a) is that the setpoint temp or the measured temp?  Setpoint temp would=20
> never change but measured temp might... say, +/-1 count?
>=20
> b) you mention displays that have run longer but did you have some means=
=20
> of recording what the brightness was in their original state?  Or did it=
=20
> just seem that they did not age in such a differential fashion?
>=20
> c) your fridge probably does run in it's design spec but is that spec=20
> conservative or otherwise?
>=20
> Five years is, in this day and age, a long term observation: I like=20
> that.  If I have a single pet peeve, it is trying to scry meaning out of=
=20
> a single point of data but here you have five years of data.
>=20
> No fridge I have seen has had a 7 segment display of temps - what brand=20
> is yours?


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