# Electrical 101 help needed



## NightRave (Feb 28, 2020)

Hi All,

a while ago my Faema Carisma A1 (which is very similar to Carisma S1 and Casadio Dafnia S1) stopped heating up the boiler.

I tried many things and now I finally opened up and disassembled the machine. Now on one of the boards, I found a blown 800mah fuse. Ordered some new fuses. When I turn the machine on, and the water level is too low, nothing happens and I just get a warning on the machines screen that the water level is low. As soon as I fill up the tank with water and turn the machine again, the same fuse is immediately blown, so I suspect this has something to do with the heating elements on the boiler or smth. The pump still works and it will pump water through the head and the menu all works with no warnings. Just no heating the boiler.

I checked all the other boards and nothing is obviously faulty to me, but I have zero experience with electronics. I see there are two capacitors on two boards, that I could technically desolder and check with multimeter. Even after watching some how to videos on repairing electonics, I don't know what my path of troubleshooting should be now.

I checked the two poles on the bottom of the boiler with multimeter while having the resistance set to 200 and it gives me a reading of 37.

Unfortunately since I moved to Portugal I was not able to find any service around me so I am relying on my two crooked hands and the help of you 😐

I've attached the pics, perhaps someone sees something I don't


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## El carajillo (Mar 16, 2013)

Have you tested between the boiler terminals and boiler case / earth (in resistance mode).

Also check fill probe wire for damage to insulation / earthing.


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## NightRave (Feb 28, 2020)

I've tested the terminals and boiler case in lowest resistance mode and got no reading at all (not sure if it's good or bad).

By fill probe wire - do you mean the one that if I disable will overflow the boiler? then yeah, looks ok to me in regards to insulation.


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## El carajillo (Mar 16, 2013)

Check the element to earth (boiler case) on a higher resistance setting element to case = 0 element should be OK.

Looking on the I/n someone else had a similar problem, traced to the fill level sensor in the tank, (try raising it / moving it) also check leads from sensor.

It does sound as if the lead to the sensor is shorting out when the water in the tank closes the contacts ?


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## NightRave (Feb 28, 2020)

El carajillo said:


> Check the element to earth (boiler case) on a higher resistance setting element to case = 0 element should be OK.


 I tried both of the heating element to the boiler case. When I switch my multimiter to resistance it shows me 1 by default when idling. When I put in on higher resistance and check between the bottom elements to boiler case it doesn't change from 1.

I know the black wire goes to the fill probe, no idea what the red probe is. One thing I discovered is that when I wiggle very briefly the third probe, the machine switches into a mode with an exclamation mark and seems there is a bad connection on the wire. I also don't know if this probe suppose to be so short of if it's end broke and is now stuck in the boiler (on the picture)

Also, I blew through all my fuses, ordered 20 more for experiments. Anything else you think I can check while waiting for the fuses?


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## El carajillo (Mar 16, 2013)

Trace that lead back to see if you can find it's source.

Have you checked the sensor at / in the water tank ?


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## NightRave (Feb 28, 2020)

Sensors seem to be fine. I did manage to make sure the temp probe is good. Now I have a very stupid question though. Can it be that I might have ordered wrong Fuses? I was basing my assumption on the stuff I found online, but by looking at the machine I might also now guess, that instead of 800mah/10Amp fuses I'm trying to feed it, this board actually requires the 8A and 500mAh. Can you look at the image and confirm/deny?


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## allikat (Jan 27, 2020)

The "wrong" fuses will be ok for testing with. They are a higher rated than the ideal, but if you're going to use up some fuses testing, then they'll be fine. Just use the right ratings when it's finally working right.

The 8A-T means it's a time delayed 8A fuse. It's more resistant to short period overloads than a regular 8A. IE: You can run a 9-10A load on it for a few seconds without it blowing, say about long enough for half an espresso shot. So when the heater kicks in as the fresh water drops boiler temp during the shot and pushes total load up over 8A for a few seconds, it'll cope fine. It just won't like that load over an extended period. Note most fuses don't blow at exactly their rating anyway, and will accept short peaks above it fine, it's just not quite as predictable in action as a lower rated fuse with slow blow or time delay.

A normal 10A fuse should have somewhat similar characteristics.


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