Hey--
Picked up an old ECM Giotto a few weeks ago, and trying to get the thing running. (so far to no avail)

The machine's light turns on, but that's about it. The old over-temp sensor was broken, so I've replaced it. (even when bypassing it to the pressure-stat didn't have any luck).

I've read through a bunch of posts and sounds like sometimes it can be a bad control box that wont register water levels (either within the boiler or the reservoir) but I'm not exactly sure how to diagnose it. Dont really want to shell out the cash for a new control box (currently has a giemme) unless I know it's definitely the problem.

I wasn't able to unscrew the heating element, but checked it with a multimeter, and seems to be intact.

Any suggestions on how I could diagnose? Can I just short the boiler & reservoir to ground to bypass and see if they're the culprits?

Many thanks! can definitely provide more info as necessary

You have the same control box as the gentleman with the Nuova Simonsays. Note relay K1. This is where the internal power comes from to energize all the other relays. It is a form C relay which means that it has a set of NO and a set of NC contacts. The NC contacts power the light that you see. It is the low water sensor that initiates this relay and closes the NO contact and opens the NC contact. No water, no internal power, and no machine functions. The low level probe has to be clean or you can ground to the tank to get the pump running. The purpose of all this is to prevent a dry boiler heating element meltdown check writing experience. If you can't get any response out of the control box once there is water in the boiler or reservoir. (This box is used in a couple of different machines with either plumbing or you carry the water schemes.) then someone like me needs to look at the box or splurge and buy a new one. Remember, every new part out of Italy keeps that country afloat. They can't do it without us.
Remember, it's your right foot so your mileage may vary...
jpboyt

All of the electrical diagrams of Giotto that I have seen show that this light is simply powered by the main on/off switch and not by K1. Otherwise, K1 does what you say, for sure, but the light has the typical dashed lines on the box schematic.

The Nuova Simonelli problem that James Boyt is referring to is here: Oscar boiler won't fill

Your water reservoir should have two wires going to it. Assuming this to be the case, one of those wires is connected to a good chassis ground connection; the other makes its way back to the control box. If you connect these wires, you have fooled the control box into thinking you have water in the plastic reservoir.

Make sure you have that reservoir filled and have the heating element DISCONNECTED. The machine should now function normally (other than heat). If this be the case (possibly wishful thinking), reconnect the heating element and you can check the rest of the machine out.

I would suggest You unscrew and open the controlbox and and have look on the inbuilt reley. If the malfunction is in the relay You can see it's burnt. Then it's easy to repair to a low cost, less 5$ for a new relay.
I have had this problem with my Giotto.// Regards Johan.

I believe that the dotted or dashed lines you mention means that the connection is optional. You are correct on the Giemme box in the picture, as there are only 6 wires on the high voltage side. The Nuova Simonelli machine has 7 wires which means that the light is controlled by the form C relay. Either way, if the low level or reservoir sensor is not satisfied, there will be no power to the other relays. The burnt relay in this box is often the relay that controls the heating element. Real espresso machines use other forms of element switching and the pump relay is the one that gets toasted. That's my story and I'm sticking to it... Or at least until it get's real embarrasing to maintain the position...
jpboyt

My ECM Giotto looks identical inside, except for the wiring and controller. On mine, the light gets live and neutral directly from the switch with no help from the controller.

A while back I had the same symptom. I did a little troubleshooting mostly to make sure it was not due to a bad connection on the reservoir sensor and decided it must be the relay that shuts everything down when the reservoir is low (same thing jpboyt is referring to.) I wasn't up to tearing the controller apart and diagnosing and soldering relays, so I sent it to Boyt Enterprises who did a fast and reasonable repair.

Hopefully, Boyt Enterprises is still in the business - jpboyt would know for sure about that.

Thanks for the quick reply all--

So it definitely has something to do with either a relay or a sensor. Yesterday (after posting this) I bypassed the box and wired directly to the heating element, and it (the element) worked!

I'm a bit confused about testing the reservoir sensor. Basically-- it's a single wire that connects to the top of the reservoir. There are four prongs that hang down into the water, leaving a small gap at the bottom (for when the water gets low)

Is it supposed to provide a voltage, or act as ground? I read somewhere that sometimes these sensors have a few volts from the water?? if ground-- then I imagine just grounding the wire should do the trick? otherwise it's a relay in the box?

I did open up the box yesterday, and couldn't see anything that looked charred or different from normal. (not that I'm much of an expert in visual diagnostics of electronics)

The circuitry that senses the water level in the plastic reservoir is a "capacitive sense" . . . operating similar to the touch screens found on computers, ATM's, etc., etc. See this as but one example: http://ww1.microchip.com/downloads/en/A ... 01101a.pdf

As I said previously - there must be two wires or two connections to the reservoir. Are all four prongs electrically connected? Maybe two of them are grounded when the machine is fully assembled and the other two are connected to this one wire.

. . . it's a single wire that connects to the top of the reservoir.

If this one wire goes back to the control box, then yes, you can ground it and that SHOULD cause the machine to operate. How much water is in the boiler?

The prongs are electrically connected because they rest on a surrounding metal rim. A bit hard to explain so i took some pics

sounds like i should be able to ground it...

OK - so where does that blue wire go?