Newly acquired Microcimbali Liberty: had a few restore questions - Page 4

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
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drgary
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#31: Post by drgary »

Here's the next phase of that contact restoration. I covered the post with some more of Doug's high heat epoxy and coated it with glyptal after it dried, making sure a screw can still fit into the threads for a contact connection.



Gary
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What I WOULD do for a good cup of coffee!

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drgary
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#32: Post by drgary »

Today I had a chance to ponder this machine. Essentially this is my model: http://www.francescoceccarelli.eu/Macch ... 34_eng.htm As a new restorer, there are many things I'm still learning for the first time:

How to treat slightly rusted screws? I used a wire brush to clean them and then oiled them (they won't be exposed to brew water).

How to rewire the machine? I've fixed the broken contact and have obtained new clips and a new wiring harness. But I'm still perplexed about the electrical connections and find that the picture I took wasn't adequate. Others have said to create a circuit diagram before taking a machine apart. I've never done a circuit diagram but did look at the basics on Wikipedia, and the circuits in this machine look very simple. In a next post I'll show the pictures I've got and will show the electrical components and ask for guidance. I did find an electrical diagram and description for a Microcimbali Liberty model here, http://www.francescoceccarelli.eu/Macch ... ecnico.htm but that's a later version than mine and has a single switch with the power regulated by a PSTAT. Mine has two on/off switches, one for low power (300 watts) and one for high power (1000 watts). How they interact? Nowhere to be found on the web, so I'll ask the good tinkerers here.

What about the pitted aluminum boiler? The seller only offered it to me for a low price on the condition I restore it, not part it out, so the boiler must still be intact. He said he'd been running the machine and it didn't leak. Since he was advertising it for much more and he said he'd already restored 20 machines, I find this credible, especially since his day job as guitar technician for top performers coincides nicely with his restoration hobby.

The gaskets all seem to be there and I have some Dow 111 to lube them.

There are still some parts to break down and clean, and fortunately there's a rebuild thread on the Orphan Espresso web site. Unfortunately they didn't address the rewiring of these machines, so I hope this thread will supplement that. One aspect of further disassembly is removing the spring to clean the piston and related parts. What clamp is adequate, and while I'm at it, what clamp is overkill so I can service the full commercial spring on my Conti Prestina if I ever need to do that?

I have received the case parts rechromed and powder coated, so they're ready for assembly, and I'll post pictures when I have a chance.

Anyway, I wanted to get my latest thoughts down while they're fresh in mind. The creative process here has been interesting. At first, looking at all those parts on my bench I was baffled and concerned. A couple of hours later the tasks and issues came sufficiently into focus to post them here.

What an adventure! :lol:
Gary
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What I WOULD do for a good cup of coffee!

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drgary
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#33: Post by drgary »

drgary wrote:Others have said to create a circuit diagram before taking a machine apart. I've never done a circuit diagram but did look at the basics on Wikipedia, and the circuits in this machine look very simple.
Today I found an excellent resource that is quickly teaching me all the basics of circuit diagrams, Ohm's Law, watts, volts, amps, and the various components that go into a circuit like switches, resistors and capacitors, as well as serial and parallel circuits, and AC versus DC. The site is here: http://ndt-ed.org/EducationResources/Hi ... _index.htm (I loaded this paragraph with keywords so others can find it.)
Gary
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What I WOULD do for a good cup of coffee!

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drgary
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#34: Post by drgary »

I also discovered yesterday on a visit to Christopher Cara that this is another machine that was once imported by Thomas Cara. So, I have to think Christopher's late dad for bringing me two of my machines in restoration, the other being my Conti Prestina.
Gary
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What I WOULD do for a good cup of coffee!

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allon

#35: Post by allon »

When rewiring an espresso machine, you have to take into account that the wires may be in a hot area, especially the wires going to the heating element. When I rewired my CMA lever, replaced the high current wires that go to the pstat/overtemp safety/heating element with 12ga appliance wire bought from a local appliance repair shop - it is designed for water heaters, ovens, and the like. For the low current stuff, I was able to use some leftover 16ga teflon insulated wire leftover from another project. I did a little bit of soldering to connect up to the socket for the Gicar autofill unit, and that was it.

Note that I'm pretty good with a soldering iron and understand electrical wiring.


To make a circuit diagram, make a drawing of all the things that have wires going to them, with a dot for each electrical connection; if there can be any way to confuse which connection on a thing is which, make sure there is a non-ambiguous way to uniquely identify each one. If there is no easy way, then use a sharpie to mark one and reference the rest from that one (make sure you mark the device, not the contact). Then draw lines between the dots indicating the wires.

There are some basic schematic symbols you can use for switches, heaters, etc.
Here's a randomly selected site which has some:
http://www.kpsec.freeuk.com/symbol.htm

and a useful example on drawing circuit diagrams:
http://www.kpsec.freeuk.com/cdiags.htm
LMWDP #331

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drgary
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#36: Post by drgary »

Thanks Allon,

Fortunately I got a wiring harness from Orphan's junkyard. What do you mean by a "sharpie"?

I'll soon post pictures of existing wiring and will label what I know versus what I'm not sure about. Fortunately this old lever machine is pretty simple, but I will be careful for sure!
Gary
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What I WOULD do for a good cup of coffee!

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allon

#37: Post by allon »

drgary wrote: Fortunately I got a wiring harness from Orphan's junkyard.
The insulation on wires can turn brittle and crack, especiall with heat and age.
I assume the wiring harness from OE is in good shape, though.
drgary wrote:What do you mean by a "sharpie"?
http://www.sharpie.com/

A permanent marker.
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drgary
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#38: Post by drgary »

allon wrote:I assume the wiring harness from OE is in good shape, though.
Orphan won't sell spare parts unless they're in good condition. We're talking about Doug and Barb, right? The replacement is that cloth-wrapped wiring of old but in very good shape, much better than what came with my machine, especially at the ends so that I'll be replacing fraying wire strands and rusty clips with nice, clean connectors.
Gary
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What I WOULD do for a good cup of coffee!

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drgary
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#39: Post by drgary »

You can find a split-off continuation of this thread here Rewiring a La Cimbali Microcimbali, where I'm actually working on rewiring the La Cimbali Microcimbali.
Gary
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What I WOULD do for a good cup of coffee!

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drgary
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#40: Post by drgary »

I'm returning to show further disassembly and cleaning after having figured out the wiring -- I think! :shock: I've shown that on the other thread and tried to explain the basics of electrical circuits and wiring for other beginners there. The test will come when I reassemble this Microcimbali.

At this point I've followed Doug Garrott's rebuild instructions to totally break down the machine and clean all of its parts. No need to repeat that here. Here's a link to his rebuild guide: http://www.orphanespresso.com/La-Cimbal ... 551-1.html

Here are a few details of the cleanup of what looked like hopelessly dirty parts. Cleaning them was much easier than anticipated, so I'm showing that to you. The tricky part was taking care of scale in the crannies of this elderly gentleman without exposing a pitted boiler to descaling solution. Here's an example of what I was facing, but it cleaned up very well with a wire brush.



I also cleaned up the element side of the boiler, carefully. No picture to show, but I used a small amount of solution so it didn't leak onto the wiring I'd so carefully completed. I also used a wire brush for a little more cleanup of the heating coils themselves.

One of the trickiest parts to figure out how to clean was the group cylinder, which looked like this to start:



I applied descaling solution at recommended strength (1/2 oz to 1/2 liter water) to the group cylinder with a paper towel and swirled it around with a chopstick, keeping away from the rest of the boiler interior. This and a good scrubbing with a toothbrush soaked in Dezcal cleaned it up pretty well.



Now that I'd freed it from the piston assembly and spring, I was able to immerse the piston in Dezcal for about 1 1/2 hours. Then I rubbed it with Bar Keeper's Friend on a paper towel, and it came out looking like this.

http://www.orphanespresso.com/La-Cimbal ... 551-1.html

I hope to reassemble this machine in about a week and have all the parts on hand. I'll post when that occurs.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!