Final Cappucino Maker Fix (Hopefully)

Project:
Fix that bloody cappuccino maker for the 500th time!

Difficulty Level (Easy, Medium, Hard, Insane):
Hard

Process:
Other blog post/fixes for the same model cappuccino machine:

• Fixing my Coffee Machine - May 2013
• Cappuccino Maker Leak - Jun 2012
• Final Cappucino Maker Fix (Hopefully) - Jul 2013
• Fixing a Delonghi Magnifica EAM4500 Cappuccino Machine - Jan 2017

I've had my DeLonghi EAM 4500 cappuccino maker for almost 6 years now and put between 10,000 and 20,000 cups of coffee on it so it has served us well. But, it also cost an arm and a leg ($900 used on ebay) back in 2008. So needless to say, I didn't really want to give it up that quickly and buy another one since that would have probably been outside our budget. The only option then, was to try to fix it.

The issues I've had so far with this machine over the last 6 years were as follow:

1. Leak in the top boiler (Leak Fix)
2. Broken thermal cut-off switch (no blog)
3. Broken water hose connector (Connector Fix)
4. Generic alarm
5. Water pump

#1 was a pain in the butt, but it was simply a mechanical issue so after I figured out how to make a proper gasket it was all sunshine, rainbows and cappuccinos

#2 was a simple order and replace fix that cost me about $30 bucks a few years back

#3 was definitely the easiest one

#4 was a royal PIT@!!! This, and #5, is what this blog is about

Shortly after I fixed #3 above, the machine started acting up and giving the intermittent "Generic Alarm" which was quite dreaded on the DeLonghi forums. The solutions ranged anywhere from broken motors, broken pumps, broken sensors, broken boiler units all the way to a broken triac on the main electronic power board.

When I plugged in the machine it said "Heating up please wait..." for quite a long time and then it switched to "Generic Alarm".

Somehow I deduced that it had to do with the heating of the boiler units of which there are two: one on top which does the main hot water for brewing the coffee and a second one in the back which comes after the first one and is used to create steam for the cappuccino attachment.

There could be three possible problems:

#1 one of the two temperature sensors (one on each boiler)
#2 one of the two heating elements
#3 the main power board (I have a used main power board I'd sell for $100 CAD; they're $200 new)

I found a great Parts Replacement Resource Website so I figured that the chances are fairly small for both temperature sensors to go at the same time so I ordered one replacement sensor which came to about $30 bucks with shipping.

Two weeks later I got the part, replaced it, turned it on and IT WORKED!!! Except for, it only worked for about two days! So that was no good.

Then I measured the heating elements and they registered at 14.2Ω and 14.8Ω respectively. Using Ohm's laws, and knowing that the heating element were both rated at 1000W, the voltage was measured at 123V, the amps I was drawing through the heating process should be:


I=P/V
I=1000W/123V
I= 8.13A

I measured the amperage and it was 8.2A so that was good. Then I calculated the resistance which should be:

R=V/I
R=123V/8.2A
R=15Ω

So that was pretty good too, so I knew that the heating elements were working fine.

The only logical conclusion (and this was the painfully expensive realization) was that the main power board was fried. I took it off, had a real good look at it but it didn't look burnt or anything so I put it all back together and IT WORKED!!! Except for, it only worked for about a day or so!

So, I had to bite the bullet and ordered the $200 replacement power board. Crazy to think that I'd pay more for a replacement part of a cappuccino maker than most people pay for their entire coffee machine, but the only other alternative was either a $10 cheapo walmart coffee maker that makes nothing but slop, a $100 kuerig for which the k-cups are ridiculously expensive (and I refuse to pay 80 cents for a cup of coffee at home) or another real machine for another $1000-$1500. Needless to say, my tenacity (or stubbornness as Melanie calls it) took over and I ordered the replacement board (of course with Melanie's agreement, she missed a decent cup of coffee, too!!!).

About two weeks later I got it, put it in and whoohoo, IT WORKED!!! Except for, it only worked for two days. I was NOT a very happy man, that's for sure. Melanie was getting annoyed by this time so I didn't get any sympathy from her either and I still didn't have a fix.

I think what was bothering me more than anything is that IT DIDN'T MAKE ANY SENSE. Sometimes it would work and sometimes it wouldn't. I tested and/or replaced every possible scenario and it was so inconsistently not working that I was at my wit's end. I just could not for the life of me figure out what could possibly cause these malfunctions! Frustrating!!!

The last glimmer of hope I got when I remembered something I read about the water pump possibly causing the "Generic Alarm" but since (for the most part) the water came out fine I dismissed that possible cause until the power board replacement didn't fix it.

So, last week I ordered a new water pump (another $50, but the pump was on its way out anyways) and said to myself that if that didn't fix the machine I would take a sledge hammer to it and cut my losses and go back to drinking slop.

Last night I plugged it in again just because I couldn't let it go and luckily it worked for a couple of cups but then stopped working again. Out came the volt meter (AGAIN!) and I just happened to notice that there was a little spark inside of the thermal cut-off switch (TCO) on the back boiler. Interestingly I had tested that switch many times before and it always showed continuity (which it's supposed to have), but I never tested the continuity throughout the entire warm-up cycle. As a desperate last measure (before getting the new water pump) I by-passed the thermal switch in the back and wouldn't you know it: it never gave me the "Generic Alarm" again.

Today UPS delivered the replacement pump, I put it in, found another thermal fuse that I had lying around, rigged it up and put it all back together. This may actually have been the problem all along: The thermal cut-off switch would allow power through it until the back boiler heated up just almost exactly to the temperature it would have to be for the computer to register the OK, but then the TCO would open, the power would get interrupted and the heating element would cool down again until it was cold enough for the switch to close again. And so it would go, a continuous cycle of heating, opening the TCO, cooling, closing the TCO and heating it up again until the computer said something's wrong and threw the "Generic Alarm". I guess I'll find out in the next few days, but the sledge hammer definitely IS still a possibility!!!

In summary, I paid:

$900 for the cappuccino maker in 2008
$30 for the thermal cut-off switch (TCO) in 2009
$5 for the gasket material for the top boiler in 2012
$30 for a replacement temperature sensor in 2013
$200 for a replacement power board in 2013
$50 for a replacement pump in 2013

Total: $1215

Which works out to be only about 8 cents/cup over the years plus the actual coffee grinds. This is still a saving of $21,285.00 over going to Tim's (I guess I have to justify it somehow)!!!

Videos:

Pictures:

Power board close up of the two triacs and the heat sink

Power board that didn't end up having to be replaced after all. Anybody want a $200 power board?

Inside of the water pump

The housing of the water pump

The worn-out components of the old water pump

Another view of the water pump housing

The TCO that ended up being the cause of all my troubles

Tools:
Screwdriver
Pliers

Materials:
Salvaged thermal cut-off switch
Main control/power board
Water pump

Cost:
$250

Time:
30 - 40 hrs...WAY too much for my liking

Savings:
$21,285.00

Conclusion:
Lord have mercy on me! Let this be the last time I have to fix this oh so hated and at the same time so wonderfully loved machine!!!

Additional Note:
I've had some requests to write down the steps on how to get into diagnostics mode. There are actually two different modes. Here are the details:

1. To get into Regular Test Mode: press "one shot" plus "long shot" while plugging in the machine
2. To get into Display Module Test Mode: press "two shot" plus "long shot" while plugging in the machine
3. To get into the Coffee Count Screen, hold the "menu" and "change" button while plugging in the machine

in display module test mode, each button will display "button 1", "button 2" etc to test the buttons

in regular test mode, the buttons are as follows:

Button 1 (Menu):  Heater on

Button 2 (Next): N/A

Button 3 (Change): Pump on

Button 4 (OK): Grinder

Button 5 (On/Off): Motor up

Button 6 (Bean grind): Motor down

Button 7 (1 shot): EV1 on

Button 8 (2 shot): EV2 on

Button 9 (long shot): vaporizer