Hello All. I recently bought a 110V '91 Brasilia Century.
Here's a pic:


Here is a pic of a familiar touch pad:

Here it is from the back:


The machine works great in every regard besides the fact that when I press the continuous pour button, the pump may only engage for a second or three or not at all. I may press it a few more subsequent times and I may get three to five to one to zero seconds before the pump shuts down again. Other times it may run continuously. This misery also affects the dosed buttons. The touch pad's preset times are controlled by tiny screws on the back of the pad.



I've tried in vain to adjust these to last my desired duration. I have to wonder if there is a failing electrical part or if I'm not using the force. I have no user manual for the unit, so I don't know exactly what I'm doing when it comes to programming.

Two other factors that you should know:
- I'm running water to the Century from my kitchen sink line, via a 3/8 line for about 20 feet. I have soft water in my area. I would imagine the water pressure is fine, but you may know better.
- The Century is attached to a timer. I have no reason to think that the tank is partly empty when the unit receives electricity in the AM, but you may know better.

Could this be a bad control unit? Bad touch pad? Bad water inlet valve? Bad water pressure? Could it be related to the timer?

Things to note about the machine:
I have no idea how long the unit sat and whether water was in the unit at the time. I plan on descaling it soon. I found some brown sludge in the water faucet, making me think it needs a round or two. Also, I'll backflush it soon. I don't think these things have to do with the problem, but are worth mentioning.

Many many thanks for any help you can provide!

Does changing the preset screws on the back appear to have any effect at all? The touchpads should purely operate as momentary make switches, i.e. it shouldn't matter how long you press them for once you have made contact. I had a similar problem on another machine that turned out to be a bad contact in the ribbon cable rom the touchpad to the control box, but looking at your setup, it looks like all timing, etc is done in the touchpad box, and the wires coming out are to enable the solenoids.

You still might want to try carefully removing each cable in turn (so you don't inadvertantly put one back on the wrong connector) and spraying some contact cleaner or something like WD40 or Q20 oil onto the lug and working the terminal on and off a few times to break any corrosion that may have built up. (Please be careful not to break the contacts or the lugs; it's pretty easy to do ...)

Changing the preset screws does have an effect, but it's not logical beyond the fact that clockwise = shorter and counter-clockwise = longer. However, even if I get a 20 second duration, when I return an hour later, that button is no longer 20 seconds, but 13, say. and the 13 seconds is repeatable, but an hour later, it will have changed.

I'll let you know how the contact cleaning fares. Thanks for the help.

frogsickle wrote:Changing the preset screws does have an effect, but it's not logical beyond the fact that clockwise = shorter and counter-clockwise = longer. However, even if I get a 20 second duration, when I return an hour later, that button is no longer 20 seconds, but 13, say. and the 13 seconds is repeatable, but an hour later, it will have changed.

I'll let you know how the contact cleaning fares. Thanks for the help.

I wonder if there is an RC (Resistor/Capacitor) used to regulate the time (you're likely adjusting a resistor) and perhaps the capacitor has gone bad? Or power supply issues to the timing circuit?

Mark

An update for you all:

I called Espresso Resource in LA, per the recommendation in another thread and was given the following explanation for each issue.

My first concern is that there is varying duration for each button. It was explained that we're talking volumetric dosing here, so each tiny screw is not modifying time, but volume. There is a cylindrical electonic component that has within it a small turbine. When water flows through the cylinder, the turbine spins and the elctronics calculate how many revolutions have been made. Depending on the screw setting, the delivery of water volume is measured and limited. I've done a bit of experimenting this morning, and I'm able to find some peace.

The second concern is that the delivery of water is ceasing prematurely in some cases. (I know this as the continuous pour button is ceasing.) I suspect one of the following to be the issue in the order of most likely to least:
1. Sludge/goo has collected in the cylinder, preventing the turbine from freely spinning. I have some Urnex Descaling solution on the way. I may go so far as to pull the cylinder and inspect the contents.
2. Loose electrical connections are leading to the water shutting off. (I will re-set each wire junction by un-screwing the fastener one half turn, then re-tightening.)
3. An electronic device has failed, or is failing. If this is the case, I was told that the touchpad and the control unit can be replaced in one fell swoop by migrating to a more recent touchpad that has a control unit built in. It was interesting to note that one could upgrade from one architecture to the next.

I'll follow-up with my progress.

Cheers. -Joe

Ah, it does it by volume! My Elektra T1 has one of those too. They are likely similar. When I took mine apart, it seems to be a simple affair. There is a shaft onto which a plastic impeller sits which contains a magnet. The top has a sensor that is contact free (likely a Hall Effect sensor, but this is a guess) which counts rotation of the impeller.

Mark

A final update: I loosened and tightened every wire junction and the issues (except for one that I will post in a new thread) are resolved. I'll rack it up to a loose connection. Thanks for everyone's help. Cheers.

IR receiver and emitter for dosing, no magnets. First of its kind, developed by Rossi and used on Brasilia's and early Astoria's.

Doesn't count, actually build capacitance against which the resistors (screw settings) are measured. When the charge exceeds the level set by the resistor it shuts off. There is a global setting in the computer box which you should NOT touch.

Purely analog system, the first not to use probes in tanks or servos.

Loose connections are the cause of many issues with the earlier machines. Loosen them all 1/4 turn and re-tighten.

You cannot retrofit the flowmeters to halls effect units without replacing the box.

You can replace the touchpad with a digital unit found on later portafinos. Pretty easy.

Urnex descaler with NOT help your situation. Use descaler only as part of an overhaul and use a product specifically designed for commercial espresso machines like yours.

What if you don't trust that the control box's global setting wasn't ever screwed up by a previous owner? Is there a way to calibrate it?

Because something like 4 people in the United States know that it's there and half of them our in our office.

It's a global sensitivity setting. I have never seen any adjustment fix anything. When the machines dose properly it is always something else. It was used at the factory to get it close, the small trimmers took it the rest of the way.