Saeco Exprelia grinder "still" not working after broken spring "fix"

[lifeisfun]

Hi folks!
New here, and I hope someone can give me some pointers what else could be wrong.
Tried to fix the typical saeco cracked spring that holds the brushes and no longer making connection.
Done that without problems in the past on several machines, but this time this is not the only problem.
The grinder motor will still not operate ( test mode)on the Xprelia.
Also did quick Triac check ( did not remove them from the board for the test)
The ceramic 2.2 ohm resistor is ok, and both black coils are also OK.
Also tested with another motor.
There is steady 41V DC on the grinder terminals no matter what.
Any ideas please?

Thank you!

 

[Grisu]

Could be some sort of internal failure (short circuit) on the multilayer print.
For testing it might be easier to use an old lightbulb instead of the motor.
Uncommon failure you might have to search on your own or get a replacement board.

 

[lifeisfun]

Could be some sort of internal failure (short circuit) on the multilayer print.
For testing it might be easier to use an old lightbulb instead of the motor.
Uncommon failure you might have to search on your own or get a replacement board.

Thank you so much for reply.
There is absolutely no visible damage on the board, I had backlit under microscope and everything looks like new.
Good idea with the light bulb! I'll try that!
It would be shame to discard the old board but I just may have to do that

 

[uhrmacher]

Nonsense, don't dispose of the board, it can be repaired if it's defective at all. I think there is still an error in the motor, the 41V measured are not correct, so the motor would turn. I think he is high resistance.

 

[lifeisfun]

Nonsense, don't dispose of the board, it can be repaired if it's defective at all. I think there is still an error in the motor, the 41V measured are not correct, so the motor would turn. I think he is high resistance.

What discouraged me is that another (good tested motor) doesn't work neither.
I'll give it another shot today!
Thanks for the encouragement

 

[lifeisfun]

What I find strange is that there is always voltage (41.5V DC) on the grinder connector
Test mode on or off, even when the machine is in StandBy mode doesn't matter.

 

[lifeisfun]

Digging around here using Google translator I found this post, looks like same issue as me just different board

Saeco HD8769 - Servicecode 1, Mahlwerk funktioniert nicht

Guten Tag, ich heiße Lutz und bin neu hier. Ich habe folgendes Problem. Unsere Saeco HD8769 ist nun 4 Jahre alt und vor ein paar Tagen ist der rote Schraubenschlussel mit der Zahl 1 im Display erschienen. Ich habe den Mahlwerksmotor gewechselt, da dieser nach einer Überprüfung defekt war. Ein...

saeco-support-forum.de

 

[uhrmacher]

What bothers me, 41V at the connector (if you measure a lot, you measure a lot of rubbish ). That would make the engine run.

 

[lifeisfun]

What bothers me, 41V at the connector (if you measure a lot, you measure a lot of rubbish ). That would make the engine run.

Well, what can I say, it doesn't, the voltage doesn't even drop or increase if I test the grinder in the Test menu,
Again, tested with 100% working motor from Saeco Syntia and same result.
How would you approach this?
Also noticed that usually the grinder is controlled by one triac ( the post I mentioned and others as well)
Why are there two on my board?

 

[Grisu]

Incanto got 2 triacs too, one on phase and other to ground. One of them opens the circuit for grinder and something else (brewing motor I think).
And you can check the rectifier bridge.

 

[lifeisfun]

Incanto got 2 triacs too, one on phase and other to ground. One of them opens the circuit for grinder and something else (brewing motor I think).
And you can check the rectifier bridge.

I did check the bridge but once again same as those triac it was in the board. Starting to suspect that perhaps controllers (3SD12l that controls those triac could be also bad.

 

[Grisu]

These are photo-triacs which switches triac on/off.
If you desolder the output the grinder triac must be switched off if everything else is ok.
I think also it should be save to shorten input of it, so photo-diode is turned off and photo-triac off too.
Usually they only get old and weak and dont fully open (shorten) output.

Here you can see how they are usually used in similar way in all applications inside Saeco machines.

Elektronik - Schaltplanbeschreibung Leistungsplatine SUP021YBDR samt Halbwellenbildung Incanto S-Class

Schaltplanbeschreibung Leistungsplatine SUP021YBDR in Beitrag #11 inkl. div. Teilschaltkreise alle anderen Beiträge hier tun nichts zur Sache und können getrost ignoriert werden! Hallo in die Runde! Hat jemand von euch seinerzeit das PDF mit der Halbwellenbildung einer Sirius von @hmilbradt...

saeco-support-forum.de

https://saeco-support-forum.de/attachments/muehlenstromkreis-incanto-deluxe-x_p120_muehle-markup-jpg.37553/

 

[lifeisfun]

These are photo-triacs which switches triac on/off.
If you desolder the output the grinder triac must be switched off if everything else is ok.
I think also it should be save to shorten input of it, so photo-diode is turned off and photo-triac off too.
Usually they only get old and weak and don't fully open (shorten) output.

Here you can see how they are usually used in a similar way in all applications inside Saeco machines.

https://saeco-support-forum.de/thre...samt-halbwellenbildung-incanto-s-class.62359/

https://saeco-support-forum.de/attachments/muehlenstromkreis-incanto-deluxe-x_p120_muehle-markup-jpg.37553/

Thank you, that's very helpful!
The circuit looks a lot like this, except there is two coils missing on the DC leads towards to the grinder.

 

[Grisu]

They are only not shown in this pic, it ends on JP10 and rest is symbolic.

 

[lifeisfun]

Well, extracted the board while leaving all connectors plugged in....
First weird thing is that with 0V AC on the input to the AC/DC bridge there is 41V DC on the output
When I enter the test mode and go to the Grinder menu there is no AC passing the Triacs (both)
(I never used the test menu on the Exprelia but I presume one click on the button is grinder ON, then click again for OFF)
Both G and A1 terminals on those Triacs have 120V AC all the time but Triacs output A2 remain at 0V.

 

[lifeisfun]

Tested the grinder DC circuit connecting the bridge direct to 120VAC and the motor works fine.
Desoldered both Triac and they seams to operate fine as well.

I'm done...
I guess time to order new board.

 

[Grisu]

Like I said before, there could be a short circuit inside multilayer board you wont see.
You could do the relevant circuit outside the board.
Lets say if you get correct values out of photo-triac you can build up the 2 resistors and triac manually onboard.

 

[lifeisfun]

Like I said before, there could be a short circuit inside multilayer board you wont see.
You could do the relevant circuit outside the board.
Lets say if you get correct values out of photo-triac you can build up the 2 resistors and triac manually onboard.

You are probably right, even desoldering from that board is major pain.
Got new board for $89,
you win some you lose some, oh well....
Thanks for all the info I got from you!

 

[uhrmacher]

Danger!!! In the test menu, too, the bean hopper must be closed, the brew group installed and the door closed, otherwise the grinder will not run.

 

[lifeisfun]

Danger!!! In the test menu, too, the bean hopper must be closed, the brew group installed and the door closed, otherwise the grinder will not run.

OMG
Wish I knew that yesterday before butchering that board