Magic Comfort+ redesign - Gear Motor Voltage High

[kwalker]

To Quickly to help you with your problem, we ask you to make the Following information:
- mechanical and electronic knowledge available? yes - limited electronic
- meter available? yes multimeter
- Precise name of the machine Saeco Magic Comfort + redesign. SUP012DER 120V ~ 60Hz Hello. I had a brewgroup Blocked message on this machine and found the voltage to the drive motor was too low. From the research I did, I Replaced the TIP33C transistor and the 33v 1.3W Zener diode on the PCB. My board Has Two 47 ohm surface mount resistors did tested 94 ohm across them so I did not replace these. After re-assembly, the drive motor brewgroup what going too far so the brewgroup would not lock into place Unless I released it. I opened the gear box and found the car and what overshooting the microswitch. I tested the voltage to the drive motor and now find it is too high. It is 69VDC instead of 33VDC ~. I ordered a new zener diode and Replaced it again and have the same problem. Is it possible I have a bad transistor or other trouble. Thanks for any assistance.

 

[hmilbradt]

Hi,

the problem is a bad solder point or a broken line within the gear motor voltage regulation. The gear motor voltage can't be stabilized at +/- 33 VDC.
In this situation usually the S07K35 varistor ist damaged und should be replaced after fixing the main fault ...... X_Grundprinzip_Regelung-Markup.jpg

regards
Harry

 

[kwalker]

Any chance of finding a board schematic? I have not found one. Thanks.

 

[kwalker]

Thank you. I will try to trace out these parts and the solder joints. I have a user manual and a service manual for my machine. Is there a place I can upload them so others could use? Thank you.

 

[hmilbradt]

Any chance of finding a board schematic? I have not found one. Thanks.

Hi,

There is no chance to find official board schematics at all. Saeco keeps them top secrete and does not publish board schematics. But some schematics were reinvented through reverse engineering by a forum member. Sorry, the MC+ redesign ist not included.

regards
Harry

 

[kwalker]

thanks for the schematic of this section of the board. As it turns out, the transistor was the only faulty part but I damaged some traces on the board on this circuit when removing it and the zener and ended up with high voltage to the gear motor. After repairing these traces with wire jumpers, my Magic comfort Plus is back in action. Thanks again for the advice.