I got this coffee machine from work because it was a maintenance nightmare. I'll tear it down, do the analysis on how it works and detail on some design problems as well.
It's going to be a rather long post with quite a lot of pictures. I've marked all the detected problems with an asterisk "*", I'm sure some have been forgotten as this teardown was performed 6 months ago.
(for troubleshooting see https://hackcorrelation.blogspot.de/2017/02/automated-coffee-machine.html)
General description
Initial view with some components off: the left side holds the water tank, the right side has the dregs (spent coffee) drawer and waste water reservoir.
Control panel: top left is the dregs full warning light, general warning light, descale light, coffee button, coffee quantity button, water quantity dial (ring), steam/hot water selector button (left).
The 'aroma' rotary button and coffee dispenser is disassembled and shown at lower right. Overfill drawer (drip tray / coffee cup holder) is off from the height adjustment assembly.
The pipe thing at the left is the steam outlet for milk frothing. If the droplet button (water selector) is pressed then it dispenses hot water for tea.
The top side held the beans reservoir.
From the top we can see the grinding inlet (yellowish), ground coffee outlet (round keyed hole, center right), steam selector valve (lower left), power supply heatsink (center), power button connections (lower right), infrared transceiver (bottom) and the gears from the water quantity adjustment.
Power board
The power board is responsible for supplying the control board with power and switching the heavy loads: grinder motor, boiler, water pump, flow-rate meter.
Some optocouplers at the bottom of the board and the small size of the transformer hint to a switch-mode power supply design.
*I've modified the steam selector valve (top picture, right; bottom left picture) a while back to block its output since it was leaking. I did fit new gaskets since the old ones were too worn out. New gaskets did not fix the problem so the faucet assembly (under the silver rotary button) was blocked with some screws and threadlock.
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*The green gaskets are special high-temperature silicone ones. You can see the left one has shrunk and been eaten away by hot steam during its life. If this wear is significant enough, any higher water pressure caused by finely ground coffee or scale deposits will force hot water past the faucet and down the frothing tube.
If the pressure and wear are high enough no actual water will make it into the coffee, it will all be sent down the tube.
The power board has two connections to the signal/control board on the left.
Whenever taking apart stuff it is useful to document it, for both reverse-engineering purposes and putting it back together. So I made an excel sheet having all the connections from all the boards, pin numbers and connector code:
| Power Board | ||
| 5p | JP2 | ->JP4 signal board |
| 8p | JP5 | ->JP8 signal board |
| 2p | JP7 | grinder motor |
| 2p | JP8 | intake pump motor |
| 3p | JP1 | N/C |
| 2+1p | JP4 | power switch |
| 2+1+1p | JP6 | boiler power + flow meter |
ASSY
From now on I will refer to the rotary assembly that takes the coffee from the grinder, to the water valve and to the waste drawer as ASSY. The manual refers to as 'brew group'. It is not pictured here but a quick search on Google for "Saeco Talea Giro Brew Group" will display it:
http://www.coffeemaker-spareparts.com/Saeco-Spareparts/Primea-Talea-Odea-Parts/Brew-group-for-Saeco-Talea-Odea-Primea::3896.html
The assy is operated by a motor and has the following positions and operations:
- N - low limit - lets the user take out the unit, no parts are engaged, coffee holder is in place
- rotate R
- H - high limit - coffee is compressed into the water port, lower outlet valve is connected to the dispenser
- rotate L
- I - intermediary position - the coffee holder bottom raises up causing the spent coffee to fall into the dregs drawer
- rotate L
- N - some of the waste water falls into the bottom of the assy and down the inclined plane into the waste water reservoir.
*The next pic shows how much dirt accumulates during one month of very light usage. *Not all the ground coffee pouring from the top reaches the assy.
*Also, during rotation, some coffee is dropped because of poor tolerances.
*Steam coming from the waste tank under the assembly condenses and causes the spillage to bind (stick) and trigger the waste water sensor. *The inclined plane gets fouled with waste coffee and the assy gets stuck as well not being able to shed all remains.
*The waste water reservoir is also not properly aligned with the inclined plane and some water makes it onto the bottom of the unit and then under it.
Inside the assy drive mechanism we can see:
- assy detection switch, upper right
- high (H) and low (N) limit switches, center
- drive motor, simple brushed type, with a worm gear
- reduction gears (gray)
- waste water sensor (second picture)
I will detail the water sensor principle of operation later on.
Water circuit
The vibration water pump, situated at the back of the unit, draws water from the reservoir and pushes it through various hoses. There's a small flow-meter at the bottom that is used to measure water rate as well as detect lack of water.
The horizontal white cylinder is the relay for the boiler. Since the boiler draws a lot of amps it cannot be driven by the power board directly.
The boiler is at the left side of the unit, just above the water tank. *Some wires are being run unnecessarily close to this heated part, though it might have been an oversight of the technicians that last serviced it.
*Above we run into another problem: the small black pipe at the center pushes the water tank valve before the tank is properly secured to the unit. This means that if the tank is not pushed all the way in water starts to slowly leak out of the tank and below the unit, making it a safety hazard and ruining everything under it.
At my workplace, this "feature" completely destroyed the table underneath it within one year. The only way to safeguard against this is to give the water tank a punch inwards once-in-a-while and preferably immediately after refilling the water.
*Also, jolts from the other side (emptying the dregs drawer) might cause the tank to slowly come out of place with the same watery result.
I initially assumed that there is a high-pressure pump that pushes water at high psi once the water is hot enough but it seems that steam is build up from the boiler room itself and a blowdown valve keeps it pressurized.
*Since the blowdown valve is downstream of the steam faucet a slight seal failure will cause the pressure to escape via the faucet and the (unobstructed) frothing tube or the milk island output, whichever has more wear.
Control board
This is the most complicated part of the unit requiring quite an extensive write-up.
Top left, under the two resistor arrays, we have VN770K, a short-circuit protected H-bridge drive for the grinder motor. The high power resistor underneath it is connected to the "SOURCE 4" terminal which probably goes to ground.
The U12 chip is an NDS9948 P-channel MOSFET, capable of driving 60V/2.3A.
The black potentiometer is actually connected to the water quantity ring/dial assembly, so it's probably sampled through the microchip's ADC. Below that there's a jellybean 78M05 and then a part marked "32C65". It has 4 pins and it's marked Y1 so I assume it's a ceramic/crystal oscillator, though I've never seen that marking before.
The chip under the revision sticker is MCP908AP32 - part of the 68HC08 family from Freescale, a Motorola 6800 compatible successor. Fun fact: the 6800 was one of the first processors to require only one voltage supply, back in 1974.
It does have 2kB of RAM and 32kB of flash, two 16bit CCP/PWM timers, two serial modules (one with IrDa), SPI, SMBus, 8ch/10bit ADC, 32 GPIO with 8 sink and 6 source (25mA) outputs.
Next to the CPU there's an ST95040 4K SPI EEPROM, probably used to store machine statistical runtime data like running hours, number of coffees, error count and other stuff. I suppose so because the service mentioned at one point that the machine lost its warranty because it was used in an office environment instead of a home.
The interesting bit about the CPU is the IrDa connection, there's what I guessed to be transceiver on the board with an IR transparent window on top of the unit.It's marked BU7032 and has 8 pins:
- GND
- GND
- +5V
- GND
- GND
- TX? (goes to CPU)
- RX? (goes to a pulldown transistor and then CPU)
- +5V
I was not able to find any info on it.
The rest of the components from the control board are just passives or jellybean actives, with a notable 3-switch selector on the right.
The front of the board has the user interface stuff: buttons and leds, along with the slot for the water quantity potentiometer.
*A design aspect of this is that the board is really prone to flexing when buttons are being pushed. The middle part moves about 1mm when the coffee button (most used one) is pressed and this gap will get worse as the plastic retainers wear off.
*The capton tape was probably put on as an afterthought as it's really not a suitable way to guard the board against scratches caused by the springs.
Back view of the user panel assembly, showing the tension/return springs for the water/steam selector button.
Just for reference, the steam selector valve/faucet is driven by a magnet coupled to the rotary button that closes some reed/magnetic switches.
The control board has quite a mess of wires and connectors so it's always a good idea to mark and document them. It proved especially useful (aside from the pictures) when I put the unit back together 4 months after I've taken it apart.
Initially the plan was to design a new board for the unit that worked around some firmware flaws: not being to rinse and descale the machine properly, dumping ground coffee AFTER figuring out that not enough water is available, dumping coffee randomly, poor indication of available water level, no auto power-off, etc.
You can see that after the initial rough documentation of the needed inputs and outputs this proved to be a non-feasible goal as too much R&D was required on my side, far outweighing the cost of dumped coffee or a better unit.
| Pins | Label | Ground pins | +5V pins | Signal/other pins | Description | Digital in (hall/mech switches) | Cap sensors | Analog in | Digital Out | Analog Out | Unknown |
| 2 | JP10 | 1 | 0 | 1 | boiler temp sensor (NTC/PTC) | 1 | |||||
| 4 | JP1 | 1 | 1 | 2 | steam valve selector | 3 | |||||
| 5 | JP7 | 2 | 1 | 2 | bean cover (2p) + grinder motor sensor (3p) | 1 | 1 | ||||
| 4 | JP2 | 1 | 1 | 2 | serial comm? | 1 | 1 | ||||
| 10 | JP5 | 3 | 1 | 6 | motor limit switches (3x2p), assy misplaced switch (2p), assy motor output (2p) | 4 | 2 | ||||
| 6 | JP16 | 2 | 2 | 2 | intake pump sensor (3p) + intake water level sensor (3p) | 1 | 1 | ||||
| 5 | JP4 | 1 | 1 | 3 | power/main board connector | ||||||
| 8 | JP8 | 0 | 0 | 8 | main board connector | ||||||
| 4 | JP3 | - | - | - | N/C | ||||||
| 2 | JP21 | 0 | 0 | 2 | side cover (assy/dregs) open switch | 1 | |||||
| 6 | JP23 | - | - | - | N/C (1 gnd + 1 5v) | ||||||
| 3 | JP22 | 1 | 1 | 1 | waste water level sensor | 1 | |||||
| I/O | |||||||||||
| PB1 | 1 | coffee qty button | 1 | ||||||||
| PB4 | 1 | coffee start button | 1 | ||||||||
| PB3 | 1 | water/steam button | 1 | ||||||||
| DL9 | 1 | empty dregs LED | 1 | ||||||||
| DL1 | 1 | heater on/heating LED | 1 | ||||||||
| DL4 | 1 | warning LED | 1 | ||||||||
| DL5 | 1 | descale LED | 1 | ||||||||
| DL2 | 1 | coffee on LED | 1 | ||||||||
| DL6-8 | 3 | coffee qty LED | 3 | ||||||||
| DL3 | 1 | water on/steam off LED | 1 | ||||||||
| P1 | 1 | water qty potentiometer | 1 | ||||||||
| 59 | 42 | 14 | 1 | 3 | 10 | 0 | 3 |
A good idea when sketching up these things is to count which pins are connected to ground, which are connected to digital power. The remaining ones will show you how many GPIO pins you require. Then you have to analyze the signal pins and figure out which are analog, which are digital and which are something else, so you can choose the uC with the required number of ADC channels.
Almost all the safety switches are hall sensors, thus magnetic-based. This includes the side covers open detection, bean cover and dregs drawer detection. It's useful to have a handful of magnets around when testing the unit with covers removed.
Water sensor
What I though initially to be capacitive sensors (for water sensing) are in fact a turnkey solution that outputs a digital level.
They are TS100 TouchCell units, probably custom tuned for Philips/Saeco.I think the two resistors along with the PCB capacitor on the other side forms some kind of configuration that oscillates only above a specific capacitance.
The 6-pin IC takes 5V, ground, a common pin between the resistors and the two [differential] RC inputs and outputs HIGH whenever the capacitance threshold is reached, within 150us.
This can be achieved with a 555 timer and a Schimtt trigger.
Consider the following article: http://www.digikey.com/us/en/techzone/sensors/resources/articles/liquid-level-sensing.html and the last schematic. If the output of that 555 is integrated through a capacitor and fed through an op-amp in a Schmitt trigger configuration then the required output will be seen.
Maybe a single opamp can do both integration and triggering. Maybe the entire design can be done with a single or dual opamp package in a relaxation oscillator setup. Who knows, it needs some experimentation.
*The only problem with this setup is that it is not able to tell how much water is present, making it impossible for the machine to estimate whether enough water is available in the tank for a coffee of the selected size.
*The same sensor is used also for waste water sensing where it is too sensible, especially when coffee residues are present.
Hopefully Philips did not pay a lot of money for these sensors because even though they simplify firmware development they are not really able to quantify levels of detection. My guess is that they just order a few tens of millions of these and use them everywhere they get the chance to, even in cheaper units which do not have a microprocessor controlling the stuff.
Grinder unit
The grinder has an interesting design starting with a clean isolation from the outside. You can see there is no coffee residue near the motor. Top is the rotating center shaft with the non-rotating adjustable gear. Upper right is the grinding outlet.
The small wheel in the center rotates the big adjustment wheel, changing the coarseness of the ground.
The adjustment actually varies the distance between the two ceramic grinders.
The lower wheel is driven by the brushed motor through a worm reduction. Notice the black rectangle with a connector on the lower side of the bottom cover. Also notice the two black magnets on the white gear.
The black box houses a 4-pin device marked 506K 6373. It's most likely a hall effect sensor and its output is sent to the CPU to determine the grinder rotational speed. From there, the CPU can determine if the grinder is stuck or out of coffee (spinning too fast).
Conclusion
There are a tons of things which I've forgotten since the time I opened up the unit. It was a good idea to take pictures at each step since without them the machine would probably still be in pieces.
What I assumed initially to a be a straightforward analysis of a simple machine yielded surprising findings. It is indeed not trivial to design a good automatic coffee machine, even less so to do one that gives good-tasting coffee like this does. I did assume however that many years of iterative design have gone into this and expected to find mostly only firmware mistakes. To my surprise, most of the problems with this machine and its slow death have been mechanical and hydraulic.
This article could have easily been five times longer and with ten times more pictures but everyone has a limited attention span. I might detail some inner workings and findings in separate posts.
Hi-
ReplyDeleteI have a Saeco Talea Touch Plus that although new (less than 300 dispenses less than 3 yrs old and flawless visual condition) has an interesting failure. If you power it on the LED touch screen display just barely flickers with no text or graphics shown, its just barely coming on and off (I think its the back light) but nothing else happens. Its totally dead but for that small sign of life. Then, if you leave it unplugged for a good while (days) and turn it on, sometimes it comes on completely normally with 100% functionality in every way and makes great coffee.
I was thinking about looking an the power supply capacitor as a possible failure point, perhaps the supply voltage has dropped enough that the back light is flickering and nothing else is coming on (or the LCD is trying to come on). Since you have managed to do what I also have done (this is my second one- I started with the Touch that was broken (30,000 dispenses) that I got free and replaced the motor, some liquid lines and the grinders and its still working... but leaking.. so I want to get my new (again, someone else gave it to me as dead) one working, but am unsure where to look for the issue.
It is very difficult to repair a automatic coffee maker but with these steps it now becomes much easier.Thanks for sharing.
ReplyDeleteRegards
Finn Felton
Kopi Luwak
Finn: thank you for the nice words.
ReplyDeleteRufessor: if you have and oscilloscope I would prove the 5V line, perhaps it's oscillating. Check for bulged caps, if the machine is one for extended periods of time the top gets quite hot. I'm sure it is by design as well, to warm up the cups left on top of the unit.
The backlight looks like a led one so there should be no high-voltage supply for it. But anyway, the symptoms point to a bad supply voltage (regulator or caps).
On my unit the leaking happened on the frothing dispenser which was never used anyway, so I just stuck the water line to normal coffee mode by putting blue threadlock on the internal [metal] element of the faucet/selector. It's like hardcoding, but for hardware :)
Hi, very interesting post and blog ! I have a Odea Giro ( wich from what i can see uses the same hardware) and im having trouble too with the steamer valve selector ! I cant stop it from leaking . Its leaking from the (top) metal clip. What kind of screw/repair did you perform here ?
ReplyDeleteThx
Mat from Montreal
I blocked the line for the steam/frothing completely. I did this by screwing a drywall screw with loctite into the "faucet" instead of the line going out to the steam pipe.
ReplyDeleteI did buy the o-rings for that piece (see picture 5) but they did not stop the leaking. The only thing fixing it (for me) would be a new water selector assembly but I don't need frothing. It makes cleaning harder though, when descaling all the water goes to the water waste tray, requiring frequent emptying.
Two questions:
ReplyDelete1. Brewing cycle time on my Saeco Syntia is 15 sec. It should at least 25 sec. What could be done about it?
2. With a hopper full of beans, at the very end of grinding cycle, machine displays "out of coffee" fault and throws ground coffee out.What could be done to force the machine to continue and the brewing?
Positive site, where did u come up with the information on this posting?I have read a few of the articles on your website now, and I really like your style. Thanks a million and please keep up the effective work.
ReplyDeleteclick here
See also http://hackcorrelation.blogspot.de/2017/02/automated-coffee-machine.html if you're having problems
ReplyDeleteHi pleas for help. I have problem with Saeco Odea Giro. TYP 0310R ser. number. 9007SA40523803 Please help for repairing the machine. I bought the automatic coffee machine second hand. After unpacking, I discovered that someone was intruding into it (cracked plastics and handles). By common check, I discovered the 1st fault - a broken piston (catalog number 11003468). This is quite a common fault with these machines. 2nd defect leakage of the valve. Even one O ring was missing. I replaced all O-rings with new ones. Then I went over to check the individual sensors: Level sensor in the tank - OK Sensor closed coffee bean hopper - OK Sensor of closed door on the brewing unit side. - OK Sensor on the waste container - okay When I wanted to try switching on a microswitch that detects the presence of the brewing unit in the hole, I did not find contact. So I removed the wall behind the brewing unit and found that there were two microswitches near the toothed wheel. I checked their functionality. Both well. I assumed that one of them was not at his destination. The one with the green connector I supposed to indicate that the brewing unit is in place. I moved him to the top. I checked the state of the electric motor and lubricated the gear. I returned the wall back. Next, I ran the diagnostic mode and checked other components: a) Boiler - Heats up b) The pump - presses correctly and the green diode flashes during its operation and shows the activity of the flowmeter c) solenoid valve - switches correctly d) the grinder grinds and during its operation the green diode flashes and reveals the activity of the speed sensor in the mill e) the brewing unit is moved to the top position and to the basic position without any problems Other things I've done: The whole coffee maker is cleaned, deep decontamination is performed using the diagnostic mode. Check the flow meter (clean without oxidation). Check the tightness of all hoses. Both boiler thermostats are checked. Removed and thoroughly cleaned the mill. Despite this, the machine behaves as follows: Turn on the machine and fne the mill shaft. The red exclamation mark flashes very quickly. The green light of the boiler heating is not lit or flashing. However, the boiler is heating up properly. When I eject the tank (water flow), the red exclamator lights up permanently. After the tank returns, the red exclamation mark will flash rapidly again and the green indicator (the boiler is heated) will light up properly. When switched on, the Indycatter does not light the cup. Only a drop of water drops and coffee beans lit up. Can not prepare coffee, can not refuel hot water. All this can only be done in diagnostic mode. In the diagnostic mode, I also de-aerated the machine. Both the nozzle and the coffee outlet through the brewing unit. Self-cleaning will not start. I do not know anymore, maybe there is a bug in the electronic panel. Will anyone advise me? Thank you. video on youtube https://www.youtube.com/watch?v=eJuBPC35hEs
ReplyDeleteSorry, video is not available.
DeleteDoes the machine run water through the steam pipe when you turn the knob above? (for frothing)
Rapid flashing usually means pipes are clogged or have air. Doing the above for a few seconds resets this.
Slow flashing usually means attachments are missing: water tank, dregs tank, beans cover, side cover. Most of those have capacitive or inductive sensors (you can use a magnet to check those).
The microswitches near the assy detect the end position for the rotating assembly. Check that you can manually rotate it, when outside the unit, make sure that the "rotating knob" on the assy lines up with the arrow when setting it back into the unit.
Amazing work. This is the most detailed post I found and is very helpful. I have a question...
ReplyDeleteI own Saeco Odea Giro. Having problems with the brew group motor.
After taking apart and using the test mode, I believe that the motor is faulty. It works but it's like it doesn't have enough power to move the parts as it should. Does that make sense?
When I let the motor run with no load, it works, but when it is properly connected through the gears to the brew group, it gets stuck mid way.
Should I replace the motor?
Which is the right one? And where would you buy?
Or any other idea?
Check to see that the brew assembly is in the proper neutral position when inserted and that it can be turned by hand. There is also a plastic clip that needs to be raised, on the inside, otherwise the assembly doesn't sit properly and cannot be turned.
DeleteCheck the lubrication and for missing teeth on the plastic gears.
Otherwise, I can check my old pictures to see if I took a photo of the motor, I remember being a DC motor at 12V or 24V.
Best if you search for your exact part as my machine may be different.
Again, I would suspect the gearing and meshing more than the motor.
bonjour ;j ai un probleme avec la machine le voyant point d exclamation ❗ clignote rouge et la machine s allume et ne fait pas de café .j ai fait un detartrage mais ca arrive pas a terme .merci de m aidé
ReplyDeleteIs it flashing quickly or slowly or is it steady? Steady LED might mean it detects water in the brew unit or no water in the tank. Slowly flashing might mean some parts are not properly fitted (microswitches or magnets broken). Flashing quickly might mean there is overpressure in the circuit, try force descaling several times.
DeleteLast, check that the faucet above is exactly on the coffee position and not in-between coffee and frother.
Hi,
ReplyDeleteI have the following problem on Seaco Talea Ring machine:
the machine makes good coffee when it works but most of the time rejects the freshly ground coffee in the dispersing bin and ask to add coffee to the grinder bin regardless that the bin is almost full of fresh beans... I wasted more than pound of coffee already trying to troubleshoot and find any dependencies of what or how is this happening. any hints please?
Possibly the engine rotation sensor is broken.
Deleteif anyone was wandering: I found the problem. II was feeding the machine with power from inverter that was not sine-wave but rather modified sine-wave. That was disturbing the electronic counter for the coffee grinder making it count twice as fast thus the logic was fulled that the grinder bin is empty. connected to line power and all works great! replaced the inverter with pure sine-wave and no problem ever since...
DeleteInteresting finding. Wondering if some clamp-on ferrite things on the power line or the motor wires would have mitigated this.
DeleteI have a Talea Touch that works with preground coffee but when I press the button to make coffee using the grinder, I am asked to shut off power so the machine can restart to correct an error. No error code is provided. Do you have any idea what the problem might be?
ReplyDeleteDoes it start grinding? If it does, but throws out the coffee, then the ground coffee sensor (funnel) might be damaged. If it start grinding but stops after a while the grinder motor sensor has a fault. If it doesn't start at all, no idea, never heard of this before, perhaps there is no power to the motor or the relay/SCR is broken. If you manage to fix it please share here so others can learn from this.
DeleteIt was a problem running on modified sine-wave inverter and generator. It runs fine on pure sine wave inverter and grid power. Obviously the coffee sensor/detector is too sensitive on clean power.
Delete