# Connecting mcu - mcu

**URL:** <https://forum.sovol3d.com/t/connecting-mcu-mcu/5233>\
**Category:** Sovol SV07 Plus\
**Created:** [June 29, 2024, 3:12pm UTC](https://forum.sovol3d.com/t/connecting-mcu-mcu/5233 "2024-06-29T15:12:39Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Ernst](https://avatars.discourse-cdn.com/v4/letter/e/9f8e36/32.png) [@Ernst](https://forum.sovol3d.com/u/Ernst)\
**Post date:** [June 29, 2024, 3:12pm UTC](https://forum.sovol3d.com/t/connecting-mcu-mcu/5233/1 "2024-06-29T15:12:39Z")

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Hello everyone  
I am a SOVOL newbie, wanted to start over after 7 years of 3D break, and got myself an SV07 Plus.  
The printer arrived within a week and I had no problems assembling.  
At the start, however, I could not get beyond the Klipper initialization.  
“mcu ‘mcu’: Unable to connect  
Once the underlying issue is corrected, use the  
“FIRMWARE\_RESTART” command to reset the firmware, reload the  
config, and restart the host software.  
Error configuring printer”  
After a 3D expert and I tried everything (firmware reflash, new USB cable etc.) I contacted the SOVOL support. The request was immediately forwarded to the engineers who promised to send me a new motherboard and a new USB cable. Both arrived today and I replaced the motherboard and cables, unfortunately without success, again the screen could not connect to the mcu.  
I must have reached into the toilet again and could not yet make a single pressure. I am now really angry and consider giving the printer back.  
Does anyone else have a solution?

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**Author:** ![tingo](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.sovol3d.com/tingo/32/1731_2.png) [@tingo](https://forum.sovol3d.com/u/tingo)\
**Post date:** [June 29, 2024, 5:11pm UTC](https://forum.sovol3d.com/t/connecting-mcu-mcu/5233/2 "2024-06-29T17:11:03Z")

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Are you sure that all cables are connected the way they should be, and are firmly inserted in the sockets? You probably already checked, but please double check against the documentation.  
It sounds like either a power cable or a data cable is missing / not properly connected.

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**Author:** ![WeeGudOleChap](https://avatars.discourse-cdn.com/v4/letter/w/ea666f/32.png) [@WeeGudOleChap](https://forum.sovol3d.com/u/WeeGudOleChap)\
**Post date:** [July 6, 2024, 5:52pm UTC](https://forum.sovol3d.com/t/connecting-mcu-mcu/5233/3 "2024-07-06T17:52:02Z")

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Ran into the same issue Ernst and checked everything do you know what wire was loose?

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**Author:** ![Ernst](https://avatars.discourse-cdn.com/v4/letter/e/9f8e36/32.png) [@Ernst](https://forum.sovol3d.com/u/Ernst)\
**Post date:** [July 6, 2024, 7:38pm UTC](https://forum.sovol3d.com/t/connecting-mcu-mcu/5233/4 "2024-07-06T19:38:00Z")

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Yes, it was the wire for the filament sensor.

Greetings, Ernst

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**Author:** ![JohnStef](https://avatars.discourse-cdn.com/v4/letter/j/8e7dd6/32.png) [@JohnStef](https://forum.sovol3d.com/u/JohnStef)\
**Post date:** [January 29, 2025, 12:40am UTC](https://forum.sovol3d.com/t/connecting-mcu-mcu/5233/5 "2025-01-29T00:40:37Z")

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I recently had a MCU Config error, I went thru the usual “restart” attempts and no go. At the time the error occurred it was 20 deg F in my garage, I just went out and turned it on and it fired right up and homed normally!  
It is 32 deg F. Whew! Very happy.

The colder temp exceeded the acceptable operating range.