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Topic: Alpenrost malfunction after cleaning (7 msgs / 165 lines)
1) From: David Kingsley
Hi,
New to list, hoping this falls well within scope:
After thorough cleaning of inside of Alpenrost, heating element seems to go
full on at beginning of roast cycle, and stay on bright orange like a
toaster element. Then after a way premature 1st pop at a little over 8
minutes, element goes off for long time (about 8-10 minutes?) stays black,
no doors open or anything for cooling, then element come back on for a while
to a rapid 2nd pop nearly burning the batch before manually initiating cool
cycle. 
Using measured 225g batches, last try with Tom's Ethiopian Sidamo.
There used to be an oscillation between two tones, as though the element
comes on and off every few seconds. This would be the case from a minute or
so in right to cool. Now just one long tone that only changes once every
8-10 minutes when the element goes on or off.
Took it apart to see if anything obvious, nothing I can tell. Swissmar not
much help until after Nov 7.
Anyone have a schematic? Similar experience? Any help greatly appreciated!
David

2) From: Rick Farris
David,
It sounds like your Alp has a problem, but much of the behaviour you're
describing is normal.
At the beginning of the roast cycle the chamber is cold and the heater
comes on full blast to bring it up to about 500F.  As the beans get
closer and closer to 500, it doesn't take as much heat input to
maintain the chamber at the proper temperature.  After a while, the heat
being input to the chamber isn't enough to make the heating element glow
orange any more.
If you have a variac with a current meter, or even better a
"Kill-a-Watt," then you can watch the forementioned effects.
It sounds to me like your loop feedback is being attenuated, so that
you're having some serious over- and under-shoot on your temperature
target.  It is most likely an electronic problem, but could be something
as simple as the feedback temperature sensor coming loose from it's
mounting.  On the Alp v1.1, the sensor is near the left hand side (as I
remember, anybody else with better memory, jump in here), near the air
inlet slots.  You might check it and make sure it's mounted securely.
-- Rick

3) From: Rick W
Hey Dave,
Was your cleaning job limited to with the skins "on" or did you take the
Alp apart?  About once a year, I take mine apart and do a more thorough
cleaning and lube of the flapper door gears.  If you didn't take it
apart and didn't possibly dislodge a connector, then is it possible some
liquid from your cleaning efforts may have gotten down to the circuit
card under the fan?
I know what you mean about the "two tone" sounds that start about 2mins
into the roast.  That is the heater cycling on and off and a working Alp
will do that all the way until the Cool cycle is initiated.
What's up with SwissMar not being able to help you until Nov 7th?
Rick Waits
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appreciated!
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4) From: David Kingsley
Alp apart. Would the thin two ended wire attached to the bean cup end of the
element have something to do with a temp sensor feedback loop?
On 11/3/03 6:38 PM, "aW"  wrote:
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5) From: David Kingsley
Bruno is out until then.
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6) From: Rick Farris
It might.  I never took mine apart to see exactly what it looked like...
-- Rick

7) From: Rick W
Yes it very well could, especially if your Alp is one of the newer
designs that adjusts itself due to ambient air temp changes.  My Alp is
the original design that doesn't have that capability.  It would make
sense that there's a sensor near the cool end of the Alp (bean cup area)
to sample the air temperature.  I don't have any schematics of the Alp,
but would like to have them.  Please keep us tuned into what you find
with your Alp.
Rick Waits
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Alp
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