Mahlkonig E80s GWB stalling on light roast beans - Page 2

Grinders are one of the keys to exceptional espresso. Discuss them here.
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BaristaBoy E61
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#11: Post by BaristaBoy E61 »

gabrielts wrote:How can I check the capacitor value?
You would need a digital multi-meter that could measure capacitance. That would be the easiest way.
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gabrielts (original poster)
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#12: Post by gabrielts (original poster) »

Yes I have dmm- just set it to measure capacitance but where do I probe?

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BaristaBoy E61
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#13: Post by BaristaBoy E61 »

gabrielts wrote:How can I check the capacitor value?
With the grinder unplugged, take a picture of the capacitor with all wires attached for reference. Unplug wires attached to capacitor. Discharge capacitor using a resistive load, such as a resistor (any low value) or even an incandescent light bulb (lamp with power switch ON) to discharge the capacitor gently, any resistive load will do. You can also, if you must, discharge the capacitor by shorting its terminals with a screwdriver. I would use that as a last resort but it's unlikely to cause any damage.

Place your DMM in capacitance mode making sure that you've selected the correct range for the capacitor your testing whose markings are on the outside. Test the voltage across the capacitor terminals to verify the voltage (DC) is minimal, if you think it's high, discharge again. Make sure that your probes are plugged into the correct sockets of your DMM to measure capacitance. Proceed to measuring the capacity of this capacitor that might in fact be two capacitors in one if there are more than 2-contacts. This would mean that it is both a start and run capacitor (2-capacitors), in this case measure between ground and hot (- to +).
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

buckersss
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#14: Post by buckersss »

BaristaBoy E61 wrote:With the grinder unplugged, take a picture of the capacitor with all wires attached for reference. Unplug wires attached to capacitor. Discharge capacitor using a resistive load, such as a resistor (any low value) or even an incandescent light bulb (lamp with power switch ON) to discharge the capacitor gently, any resistive load will do. You can also, if you must, discharge the capacitor by shorting its terminals with a screwdriver. I would use that as a last resort but it's unlikely to cause any damage.
Ideally I'd think you want to wear some resistive gloves if you are gonna discharge the caps. That may also make it hard to maneuver the load into place though.

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BaristaBoy E61
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#15: Post by BaristaBoy E61 replying to buckersss »


Not a bad idea but you're not discharging an old TV's CRT (picture tube) that can just about launch you through a wall even a month after it's been unplugged, if you get shocked. This cap will likely have a stored voltage way below the dry skin resistance threshold that is not likely to shock below ~80volts.

Point well taken if you're not used to working with electrical circuits.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

gabrielts (original poster)
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#16: Post by gabrielts (original poster) »

Checked the current today. On idle it is around 0.1 amp. When it is on it peaks to 10A and drops. Grinding is about 2 seconds as I only dose for 15g. No stalling today. Note it stalled when starting to grind and never stalled when grinding through the 15g doses.

Today it Ran smooth and hit the weight exactly 3 times I used it. Using Starbucks light roast verdana blend today which is medium roast to my taste. Very smooth and tastes a lot better than previous grinders. The onyx beans should be here tomorrow.

Checking the starting cap looks to be a bit of disassembly so will resort to that if it stalls again and will see vendor recommendations

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BaristaBoy E61
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#17: Post by BaristaBoy E61 »

Sounds about right.
Glad it's working!
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buckersss
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#18: Post by buckersss »

10 amps should be sufficient for those sized burrs I would have thought. Id be curious to hear what happens if you do what Steve said... Hot start and drop the beans in next time you buy a light roast.
BaristaBoy E61 wrote: Point well taken if you're not used to working with electrical circuits.
True everyone has different comfort levels. I'm use to working with it but I always second guess myself.

Compared to a friend of mine who is totally comfortable changing light switches and receptacles without opening the breaker.

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BaristaBoy E61
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#19: Post by BaristaBoy E61 »

buckersss wrote:True everyone has different comfort levels. I'm use to working with it but I always second guess myself.

Compared to a friend of mine who is totally comfortable changing light switches and receptacles without opening the breaker.

An abundance of caution is a good thing particularly if your understanding of what you're working with is limited. My experience is with high power audio amplifiers and transmitters both tubes and transistor, transmission lines, geothermal heat pumps and of course, espresso machines as well.


Sometimes knowledgable people can take things for granted or be in too much of a rush. It's good to slow down, assess and think about what you're about to work on before proceeding, to develop a plan that first and foremost includes safety.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"