From your pic, I see you have 2 alarms,  I attached alarms explanations for you

you need to think why the alarm happen, such you did some changing in HW? 

Your machine is Manufacturer Defined/Configuration  , you can contact them for help

Sergio@TSA

Hello

I have tried to load the backup from two different dates and the alarm continues.

Can it be the HARD DRIVE?

Someone who can guide me?

Thanks in advance

 I am sorry that I cannot provide more help. I have known 840C from 1993--30 years !, I can call myself expert on that type of CNC, 

But I told you that  your machine is special case--1st --it is gear sharping machine, all axis and spindle should run in synchronous following certain rule

  and 2nd, it was manufacturer configured (customer defined --NO Siemens Standard) 

Even If I were on the site, I can do less than normal.--I really have local customer with same  machine builder , I did more than 3 times services for them. only I can do --I suggest try to load different date of back up . go into Machine builder menu/display to run reference 

.1--"go into Machine builder menu/display to run reference"

2- check some R parameters setting ref machine builder manual 

This machine builder still available, ( I know they made new machine using New type of Siemens CNC). try to Google their contact info. if you can not fix the problem contact them     

Sergio@TSA

 Hello Nulizhang

Thank you so much for your reply.

We received this machine from another company; I don't know if they made any hardware changes recently, but they said they were using it normally.

When we connected it here, it had some power section code wrong alarms (300714). A technician came and managed to clear them, but then this parameterization error appeared, apparently related to the main spindle.

A maintenance technician from the company that owned the machine then came and tried loading previous backups, but it's still the same as the 20190 alarm.

We'll try replacing the HDD with a reconditioned one.

For the other alarm, 13401, we have a procedure to move the axes manually, but we see the signal on the screen and no axes move. A photo is attached.

BR

nulizhang

From your pic, I see you have 2 alarms,  I attached alarms explanations for you

you need to think why the alarm happen, such you did some changing in HW? 

Your machine is Manufacturer Defined/Configuration  , you can contact them for help

Sergio@TSA

Hello

I have tried to load the backup from two different dates and the alarm continues.

Can it be the HARD DRIVE?

Someone who can guide me?

Thanks in advance