Hello,
I have the Synchronika for a bit more than a year now. Two days ago, while steaming milk for two cappuccinos, the steam became very weak toward the end of the steaming. It has never happened before and though the pressure (naturally) drops through the process it is still high enough to steam this amount of milk. This is where it gets stranger. Stopping the steam and waiting for a short while brought the boiler to full pressure again, but the steam remained very weak and now keeping the valve open barely moved the needle on the pressure gauge, as almost no steam is coming out.
Well, the obvious answer would be a blockage somewhere in the steam pipe, and the first guess would be the wand tip. I took off the tip and cleaned it (even though there was nothing out of the ordinary). A day later I'm making my afternoon cappuccino again. Turning the steam wand I behold full steam pressure. OK the tip must have been the issue. No, the same problem again - toward the end of the the steam become very weak and doesn't recover.
Ideas?
I realize that I should check for a blockage somewhere else, however if the steam pipe is blocked than it's blocked. Why does it repeatedly starts normally and then gets weak without recovery.

Cheers

If it were my machine, I'd first pull the steam wand and rod it out (careful, it's lined with a Teflon tube). Finding nothing, then I'd pull the pipe that runs from the top of the steam boiler to the steam valve. See photo

You could then satisfy yourself that the opening at the top of the boiler isn't partially blocked (unlikely), Likewise the input to the steam valve (possibly manufacturing debris). And, you could easily rod-out the tube with a piece of stout copper wire, totally eliminating the possibility that there's something inside (possibly soft and moveable). Finding nothing there, I'd reattach the tube to the valve and blow in the open end, operating the valve. If still no dice, that only leaves something in the valve.

I hate saying this on a Sunday night when I'm not at work and can't check the parts-breakdown...
But I am almost certain that the Synchronika has spring-closed valve stems with the common red valve faces. Your valve face may be loose in the valve stem, when steaming, all's well for 5 or 6 seconds as the steam blows by the loose valve face heating the valve and the valve stem, eventually the valve stem heats to boiling temp, the water that's trapped behind the loose valve-face expands and extrudes the valve-face into the valve blocking most of the flow... Once the valve is allowed to shut, the valve stem recaptures the valve face, the spring forces it to, and it's hard to believe this happens, but it's the only explanation I have and replacing the valve-face, or sticking the valve-face in position with silicon so that water can't get behind it and blow it out has seemed to fix it the 2 or more times I've seen it since I figured it out. Replacing the valve-face is probably the manufacturer's recommendation, make sure the brass is very dry. A little silicon required no parts to be ordered, unless you don't have silicon at home.

Thanks JRising and Nunas! One thing I didn't mention is that I use the machine with a water reservoir. Hypothetically speaking, if there was a water contamination, e.g few coffee grains that somehow found there way in the reservoir or whatever, can it find its way into the steam pipe? As I said on the initial post if something is blocking the steam then I assume the blockage will be there causing the steam to be weak until removed. For few days now the steam starts strong and weakens after 10-12 seconds and doesn't recover even after the pressure returns to maximum, JRising theory Is more likely to explain it.

I'm reasonably sure that there's a filter under the reservoir on Synchronikas. That said, I've never had any reason to go looking for it
Now, even if a few grains of something made their way past there into the steam boiler, those grains would likely just sit on the bottom (if they were floaters, they'd still be floating in the reservoir). The steam that is taken off the boiler is from right at the top. Thus, it would be nearly impossible for something to make its way into the valve. I've not run into the situation that John mentioned, but it seems to me to be a likely possibility. There's nothing much in the steam path, and if it isn't some bit of manufacturing debris scooting back and forth in there, then the valve seat is really all that's left. I bet John nailed it; please let us know .

Monday now, and I can open the book... A Synchronika has joysticks, so I'm second guessing myself. The valve face in the joystick pushed valves is very much like the valve faces on the three valves in the E61 head. It's possible for those to deform, muffin-top, or crumble, but I'd guess that it's actually falling apart and bits of the valve face block the steam flow, rather than the valve face un-seating.

There are about 25 seconds of steady steam before it becomes very weak. After 25 seconds the boiler pressure (and temperature) is still high enough and before the problem started I have never witness such behavior. As said, even after waiting for the boiler to reach max pressure the steam is very low. Here's a link with a video to the problem
https://1drv.ms/v/s!Ak_OcW8wz1T3rmMHI3MKJzVAAMRQ
Letting the machine to cool down and then turning it on and waiting for max pressure bring us to the same starting condition.
The steam becomes weak very close to the time it takes me the steam milk for two cappuccino cups (I probably need 5-10 seconds more) for my wife and myself. I rarely needs making more than that. However, the Synchronika is designed to handle much greater workload than that

JRising wrote:Monday now, and I can open the book... A Synchronika has joysticks, so I'm second guessing myself. The valve face in the joystick pushed valves is very much like the valve faces on the three valves in the E61 head. It's possible for those to deform, muffin-top, or crumble, but I'd guess that it's actually falling apart and bits of the valve face block the steam flow, rather than the valve face un-seating.image

If that was the case, why does the steam flow is strong at the beginning? I understand that the mechanism can crumble (I like less the fact it happens in one year old machine with a once a day usage of the steam wand), but then the blockage would be permeated.
Do you understand how the mechanism works? I see two springs in the e diagram, if those get heated and then lose their ability to serve their purpose, maybe the steam flow becomes partially closed.

I'd take the valve apart and have a look, instead of second guessing what may or may not be happening inside.