Let me begin by apologizing if this topic would fit better in the repair forum - I figured I would have a better response by speaking with the lever machine guys directly.... If admins/members feel differently please let me know and I will repost there.

Background:
Over the past two weeks I decided to rebuild my La Pavoni Professional (1996) after having a very hard to push lever, and a rotated boiler (in respect to base plate). I bought the machine used, and although it was in very good condition, I suspected that it was unserviced for quite a while. I proceeded to do a full tear down as described by rpavlis (La Pavoni levers - simplified "full service" routine), and was pleased to be able to remove and replace a rusted circlip (with a stainless steel one) within the grouphead, and lubricate the internal seals with Molykote 111.

Problem:
When I rebuilt the machine and turned it back on, I began to notice electrical issues.

First, I noticed that the machine would not turn on (indicated by the power-switch light remaining dark). When I tilted the machine on it's side the power switch light would turn on, and therefore I concluded that the green power line from the pressure stat(?) to the power switch was loose at the powerswitch end. After some time I managed to push the plastic clip on the power-button end enough to the side to create a good connection and the machine turned on with no issue.

Next, after letting the machine warm up for 20-30min, I ran some water through the grouphead to remove (if any) excess residue from the grouphead lubricant. Now that the machine was warm, I wanted to straighten the boiler. Although I read about a method of rotating the boiler using a large punch at the bottom, I decided to see if I could rotate the boiler easily from grouphead using a dish towel wrapped around the grouphead and boiler like an S. It worked!....kind of... the grouphead was now straight with the base plate.

So I decided now that the machine was fully serviced and straightened, it was time to check if it would turn on. When I plugged it in and flipped the power switch, after 1-2 seconds a little puff of smoke (smoke? + steam?) came out of hole where the powerplug enters the base, and 0.5 sec later sparks exited the base plate from the same point and my breaker flipped....

After getting the power back on, removing any water remaining in the boiler, and letting the machine cool, it was time to gauge the damage. When I took off the plastic baseplate, I was shocked to see absolutely nothing. No melted wires, no black soot (although there were a few black marks left on my counter which I assume came out of the ventilation holes on the bottom of the baseplate), and no discoloration of the metal. It was as if nothing happened, although the smell of something that melted did remain.

Hypothesis:
When I rotated the boiler in respect to the baseplate I opened a small microcrack(?) in the gasket(?) of the heating element. I suspect this would have released some steam or water into the electrical section to cause the short.

Proposed Solution:
Prior to sending the machine to an professional service centre, I would like to identify the problem myself. Professional service centres are not easy to find in South Africa, and shipping to one in europe is currently out of the question.

I assume will eventually have to remove the heating element and inspect all seals along that interface, but prior to that my proposed course of action is:
1. Photograph where all the wires/plastic clips are currently located to ensure rewiring is done properly.
2. Check each wire for melting of their insulation and check every connection point for evidence of a short.

Assuming I find nothing, then I will have to go ahead and check the seals around the heating element and replace any gaskets. On my 1996 model, I am unsure whether I have a plastic gasket or a metal one, so I am hesitant to potentially break something without due cause.

After checking the above, I am able to use a voltmeter to test for resistance between components, but as I am no electrician, I am obviously resistant to put myself in unnecessary danger. I still hope I will be able to identify the issue visually and correct it without needing to turn it on.

Request to reader:
If I am lucky enough to have a La Pavoni expert read this, can you weigh in on:
1. Is my hypothesis/proposed solution appropriate?
2. Has anyone seen this behavior before?
3. Is there something I have not considered?

Any and all responses are welcome!

Please pardon my long-winded post. I aimed to provide as many details are possible to help identify and solve the issue, but also to detail the situation for anyone else who unfortunately experiences the same thing.

The assumption that your physical adjustment caused the electrical problem makes sense, but it may be unrelated. Since the problem at present is certainly electrical my first test would be continuity between different parts of the circuit to isolate the the short. Regardless of what caused it you should be able to find the part that went poof. Since you don't see anything burnt it must be a closed component like the switch. I think there are only 3 components like that in the professional: switch, p-stat, and reset thermostat.

I'm not an expert, so take it worth a grain of salt. I have done a lot of work on my machine, and dealt with shorts plenty. It makes it easier when you can see the burnt part.

It sounds like a posisble faulty switch. Is this plugged into a ground fault? (Would highly recommend if not).

Continuity tests with the machine unplugged can identify the short pretty quickly, especially if it caused a breaker trip. Start with the plug and work your way through. Make sure the switch functions, if not replace. Check ground to boiler, etc. if you are not confident with your skills ask or find someone who understands it.

Disclaimer: Electricity and espresso machines are not to be messed with by the inexperienced as it can kill you.

Absolutely agree with the above. If you use your multimeter, only do so with the machine safely unplugged.

lapavoni96 wrote:First, I noticed that the machine would not turn on (indicated by the power-switch light remaining dark). When I tilted the machine on it's side the power switch light would turn on, and therefore I concluded that the green power line from the pressure stat(?) to the power switch was loose at the powerswitch end.

No. With this switch, if the two connections from the cord to the switch are good, and the switch doesn't light you have a problem with the switch. The problem may have been with the little contacts at the lamp and turning it on its side improved that. You likely have a bad switch or a bad power cord or a bad connection between the power cord and the switch.

lapavoni96 wrote:Hypothesis:
When I rotated the boiler in respect to the baseplate I opened a small microcrack(?) in the gasket(?) of the heating element. I suspect this would have released some steam or water into the electrical section to cause the short.

I suppose it's possible that when you turned the boiler on the base, the boiler flange ring may have remained fixed with the base, resulting in a loosening or break of the element gasket. (The element is bolted to the flange ring, but seals against the boiler, so if the boiler is turned and the flange somehow stays fixed, the element seal could break.) Steam escaping from the boiler/element gasket is a common problem, and is the usual cause of rusting of the underside of the base. But I doubt this caused your serious electrical problem. An element gasket fix here would involve just removing the element with the three bolts and lubricating or replacing the element gasket. It shouldn't matter whether you have the metal or the plastic boiler flange ring if you do this.

Sparks and a breaker trip sounds like a serious short. It might even be in the cord, so check that carefully. Check for any continuity between the line-neutral and the line-ground prongs with the cord unplugged and with the line and neutral wires detached from the terminal or switch of the machine.

The machine is very simple, and could be checked out electrically by a trustworthy neighborhood appliance repair shop, even if not authorized for La Pavoni repair.

forbeskm wrote: Is this plugged into a ground fault? (Would highly recommend if not).

Good advice. In South Africa this might be called a Residual Current Device (RCD) or a Residual Current Breaker with Overcurrent Protection (RCBO) in the electrical panel. If you get a short to ground in the appliance they will trip within microseconds. They are there to help save your life but also can help save the machine.

Thank you all for your comments!

I performed continuity tests and I found that everything was fine, except for one of the main power cable wires which had a continuity value of 072 (and not closer to 000). Upon inspection of the main power cable, covered by the plastic housing where the cable enters the machine, was a 3-5mm wide hole in the insulation. I removed the main power cable, cut the cable to remove the shorted section, separated and stripped the 3 internal wires, and remeasured continuity. Continuity on all 3 wires was 008. I rewired the main power cable back into the machine and after putting the baseplate back on, it works!

I would also like to follow up at the proposed issue at the power-switch. I removed the power-switch to test continuity and have not noticed any issues. There is a little bit of discoloration on power-switch contacts, but I saw no reason to remove that. At present, there was no issue turning on the machine at an upright orientation, so I will adopt the proverb (if it ain't broke, don't fix it).

Following this thought, I eluded in my first post to a potential microcrack in the boiler to cause the short. As the short was found at the hinge-point where the power-cable exits the machine, I think it's much more likely a wear and tear issue. As a result, I have decided not to disassemble and check the boiler gasket.

It's hard to say I am out of the woods yet, as I have had the machine only up and running for about 30 minutes now. I do intend to keep an eye on any "quirks" that may resurface in the foreseeable future.

I have two conclusions I would like to share about my experience with handling an electrical issue with the La Pavoni Pro 96':

1. The simplicity of the machine, especially the electrical side, is fantastic. I feel it's not much of a stretch to conclude that if I had more sensitive electrical components, the solution would have been a remove and replace rather than a snip and rewire.
2. Electricity is dangerous. If it wasn't for a change in continuity I would not have found the short. Being able to test the continuity of the cable before plugging it back in gave me enough piece of mind that the solution was solved before reintroducing power to the system.

To those that commented: your comments were critical to help me isolate where the issue probably lies. I will remember this when I have the opportunity to enjoy my first espresso from the rebuilt machine. Thank you.