Can someone please help me identify these power mosfets in the attached pictures (I assume that's what they are!)
It is from a Rancilio epoca e2 espresso machine (circuitboard E14) They handle 220v and control 1000w heating elements....there are three heating elements in the boiler so one for each. they do not have any markings or numbers on them. they were attached to a heatsink. Looks the the resistors for them are 46ohms.
Rancilio wont help, instead they want me to buy a new board which costs nearly $2000
Thanks in advance!

 

Do you know for sure that the devices are defective, or are you ASSUMING that they are defective?

Since you are unsure about exactly what type of devices they actually are, my feelings is that this is only a “Hail Mary” troubleshooting method.
I would think that these devices are actually Triacs, not Mosfets.
Take a good close up photo, which is properly focused, and the characters clearly legible, of the white ICs which are a little away.

 

Triac eh? That is interesting. No there is definitely no identifying labels or nunbers on them

 

I edited my post. Sorry.
Please re-read again, I got other questions.

 

Thanks for the reply. You've already been more helpful than Rancilio!
For context, Im still in the troubleshooting phase with this board. I pulled it only briefly but had to put it back. Will get a better chance when the temporary replacement machine arrives tomorrow.
One of the heating elements arced (2nd hand machine, pulled off the protective cover to find limescale buildup and a water bridge)
Since then it is heating up but not shutting off so it overheats, overpressures & shuts down. I pulled the contactor, disassembled and found the corresponding element wire contact fused closed. Fixed it up but found it's not disengaging the electromagnet...turning main switch off turns it off. Circuitboard appears ok, no fuses blown and heating lights come on and go off at 1 bar pressure as per program...but a component controlling the contactor isnt working. Theres a bank of mosfets (or triacs!) over there which i will be looking into when i get the chance. Two of them lead to the contactor.

Iniially started investigating those three triacs(!), the one corresponding to the arced element isn't responding like the other two are when i poked around initially with my multimeter in continuity and diode mode

 

Triacs are easy to identify. The control terminal is on the right, whereas for MOSFETs it is on the left. There were a few old MOSFETs in the TO218 case made by Philips and SGS-Thomson.
If the power terminals are centre and left (as you look at the front with the leads downwards) then it's a triac or an SCR.
No other power devices are wired that way.
If the tab is isolated from the other two terminals, then it's a triac or SCR - No MOSFETs were made in that type of isolated-tab case.
If it switches AC then it is a triac (to switch AC would require TWO SCRs or MOSFETs)
If it is a triac, then is it faulty? Triacs generally fail short circuit. If the left and centre pins are not short, then the odds are that it works. There is usually about 40Ω between the outer two terminals in both directions on a good device.
If it has failed, then it can be swapped for almost any other triac with adequate voltage and current rating, because there are no odd triacs (e.g. sensitive gate devices) in the TO218 case.

 

Thanks Ian0, this is all great information. I am also going to focus my attention on a bank of 5 triacs on the right hand side of the board. These are controlling things like the main pump and three way solenoids and also the contactor. They are in turn being driven by a bank of white optocouplers (i googled their part numbers, TLP3062) which I will also test. It seems there's a short/closed circuit somewhere that is keeping that contactor permanently engaged.

 

OK, so I've taken the board off the espresso machine and got an ID on those three triacs:
It wasn't easy, the lettering is nearly invisible but it says BTA26800BU which I found one reference for here:
https://www.aliexpress.com/item/32393257347.html

I watched a youtube video which said I should be getting readings of about 70 if I tested with a multimeter. I'm getting readings of 25-30 for all three. Is this bad?
I tested the opto-couplers that came with them and they are good

Then I tested the bank of triacs on the right hand side and they are all giving me readings of about 70 (the opto-couplers for these are also good).

 

I watched a youtube video which said I should be getting readings of about 70 if I tested with a multimeter. I'm getting readings of 25-30 for all three. Is this bad?
I tested the opto-couplers that came with them and they are good

Then I tested the bank of triacs on the right hand side and they are all giving me readings of about 70 (the opto-couplers for these are also good).

The larger ones will give lower readings because they have bigger chips. Anything that isn't a short or open circuit indicates that it is probably OK, provided that there is no reading between MT1 and MT2

 

Aha. I have a short between MT1 & MT2 and between the gate and the centre leg on two of those big triacs. I also found a broken 317T voltage regulator, which I just replaced. I'll have to order in some triacs. Will have a look at the rest of the board and see if I can find anything else that shorted.

 

Check that the heating elements are OK. It takes a lot to kill a big triac.

 

Check that the heating elements are OK. It takes a lot to kill a big triac.

Will do. Heating isn't a problem....they will not shut off at the contactor so it overheats. I'm trying to figure all this out in my mind why the electromagnet in the contactor will not disengage...(but it will when you switch off the machine) assuming those two triacs are shorted causing the elements to stay on, the brains are thinking they are off and wanting them to stay on...or ordering them to shut off and they can't. The triac controlling the contactor is fine though, as is the contactor apparently. Then there is the faulty voltage regulator that i replaced. I would like to have this logic squared up in my mind as to what exactly is going on.

 

I was going to suggest that there had been a short and the contactor contacts had welded, but obviously not.
Is this product problematic? No-one uses a TO218 triac to switch 1000W, unless they had problem with 12A or 16A triacs failing, and someone who doesn't thoroughly understand it decides that a bigger triac would solve the problem.
Is there enough heatsinking? A 26A triac dissipates the same amount of power as a 12A triac!

 

I'm not sure if this is a problematic issue or not. Rancilio's technical support specialist just said we don't have any circuitboard schematics, we can't really help you because the board is bad, so just buy a new board. But a new board will cost nearly CDN $2,000 (yes, two thousand dollars) so they can go do one. I have a big incentive to repair this if I can. Otherwise It would be better to cut our losses and get something else that works for a similar price.

I wasn't there, but apparently there was a pop and a grrrr/crackling nose, smelled electrical smell at the elements and the breakers shut it off. I took off the heating element cover off to find that the elements had arced and shorted. Looks like there was limescale buildup over the years and this had created some sort of water bridge. The plastic spade connector covers were literally disintegrating to flakes in my fingers as I pulled the 6 connectors off. I cleaned it all up, pulled the heating element, cleaned all the caked on limescale off the elements put it all back together, covered the contacts with heat shrink, they are all nicely insulated now from any water that might drip on them. It hasn't arced since. This machine is over 10 years old, but it still pulls an excellent espresso. Well, it was I have noticed it heats up pretty quick now.

The contactor is an ABB B6-40-00, which I took apart and found one of the contactor switches welded together. I cleaned it all up, rebuilt it and it appears to be working normally, all the contacts disengage and there is no current flowing when I turn off the machine, and there is continuity and voltage when I turn it on (But I have just just ordered another one, just in case). It just won't autoregulate and switch off when it gets up to temperature and pressure (which I factory reset to 1 bar, so the board is taking programming and seems to be operating normally otherwise - the 3 LEDs indicating the heating elements are on, go off at the correct pressure, the yellow led comes on when it is filling etc.)
We also replaced the thermostat and the pressurestat, (as per our espresso machine tech repair guys suggestion) but that hasn't worked. So following this through logically, I am at the circuitboard. So I'm very keen to find components that are actually broken instead of just more throwing more random parts at it in the hope it might fix it. If the boards were maybe $200, I probably would have replaced the board. But not at $2,000. Unfortunately these aren't like xboxes where they made millions of them and there are plenty of videos & information on how to repair them.

 

Which breakers did it trip? MCB or RCCB?
The trouble with coffee machines is the best ones are designed by Italians. I have a Gaggia Cordona, and I live in an area where the water is so hard is has more carbonate than the stuff they sell as mineral water, so it does get descaled religiously.
It's like Ferraris - if you see one on the road, it's on its way to be serviced.

 

Which breakers did it trip? MCB or RCCB?
The trouble with coffee machines is the best ones are designed by Italians. I have a Gaggia Cordona, and I live in an area where the water is so hard is has more carbonate than the stuff they sell as mineral water, so it does get descaled religiously.
It's like Ferraris - if you see one on the road, it's on its way to be serviced.

Yeah and like Ferraris they come with a #$@%&! premium price to match. Don't think this was ever descaled frankly. It's the #1 enemy of espresso machines all over the world. Breakers are 20 amp dipole Siemens (not sure exactly which type), down from 30 amp circuit because the socket was initially a 3 pin 30 amp 220v, but the plug is a 220v 20 amp, instead of the standard 115v we have here in Canada. So he dropped the breakers down to 20 amp siemens ones and fitted a 220v 20 amp socket to fit the plug. Machine is pulling around 16 amps; voltage is actually 208v

 

I replaced the faulty triacs and it's working perfectly again, boiler pressure is right on the nose at 1 bar. The 3 triacs cost me $46 including shipping from mouser. Phew!
The replacement contactor should be arriving in week or so. Thanks for helping me ID those things and steering me on the right path.

 

Give it a good insulation test.
Then check how hot those triacs are running.

 

Hmmm, what would be a normal temperature? They are screwed into a heatsink, which is bolted to the metal box housing the circuit board. I did apply thermal paste to the triacs.

 

60°C is about the maximum.
I would say that if they are too hot to touch then they are too hot! But that's not sage advice for mains-connected triacs.