Wiring the power board of a treadmill

[FrodoOne]

As an aside, it is hurting my head that they used Blue as Live and Red/White as Neutral.

While I tend to agree with you, I do not know if there are any regulations anywhere which "impose" on a manufacture of any electrical product the colour-code of the wiring that must be used within any product.
Such a "manufacture" could (possibly) argue that the device concerned should be serviced only by "authorised" personnel, who would have access/knowledge of all "service" information.

 

[SFK]

Frodo,
Fully agree.
And as is often said on this site - the colour of cable does not signify what it is carrying.

On a positive note they have numbered the cables, and labeled joint points, which suggests that they were conscious in their choice and were looking to ease/improve their manufacture process.

But (on a hurting my head note) I do wish they could have been consistent - even if only having that thin read wire as a thin white wire.

SFK

 

[Salwa]

Now I'm really scared. I thought it an easy task. The person who tried to fix it before, completely ruined the treadmill. There are definitely some missing wires. Anyway, I'm giving up.
Thank you very much for warning me. SFK and Bernardgreen, I appreciate your advice. Thank you.. all of you.

 

[FrodoOne]

Now I'm really scared. I thought it an easy task. The person who tried to fix it before, completely ruined the treadmill. There are definitely some missing wires. Anyway, I'm giving up.

Never "give up". (Unless there is more than the missing input connector and the wiring concerned, the treadmill has not been ruined!)

All the information that is necessary for you (or anyone else) to "fix" the device concerned has been imparted to you by those on this site - including myself.
Check back.
There is almost a step-by-step specification of which wire needs to go where (and why) and of what needs to be removed or replaced.

A "new" Green/Yellow wire is required from the "Earth" terminal of the input connector, including a screw connector to the point labeled "0" on the "chassis".

The "White" and "Red" wires, now connected together, need to be properly connected to the "N" (Neutral) terminal of the input connector. Shrink wrapped insulation over this connection would be a good idea - but not essential.

The Blue wire with the strange object on it should have that object disconnected and that wire should be connected to the "L" (Line) terminal of the input connector.
(Again, shrink wrapped insulation over this connection would be a good idea - but not essential.)