Rigol Ds1054z channel 3 problem

[huu_tri0101]

Hi Everyone,

I recently "turn on" my Rigol Ds1054z after 9 years it has stayed in the dark.  .

I did "the self calibration test" and it get stuck at channel 3. So I hook channel 3 (purple colour) up to the generator on the oscilloscope and channel 3 can measure the signal but on the 1V,2V,5V and maybe 50V,100V scale it can't see the signal. I upload the clip here. so please take a look at it.

https://youtu.be/6JZo4Ek7j9I

I open the oscilloscope, the Pcb, the power supply,  everything looks fine to me. Does anyone have any ideas, suggestions or experience of this problem?

Any help would be greatly appreciated

Thank you


19/01/2023: More detail on the problem:

   * all remain 3 channels ( 1,2,4) are working fine with scope reference point.

   * Channel 3 problem:
           + Connect channel 3 to scope reference point
           + Push the "CH3 button": hear the relay clicks (no matter which range it's mV or V, this is the same for all channel 2,3,4 )
           + Start from 5mV to 500mV range: CH3 is able to see the signal.
           + At 1V and 2V range: CH3 is UNABLE to see the signal.
           + At 5V range: hears the relay clicks ( this is the same for other channels): CH3 is able to see the signal.
           + At 10V and 20V: CH3 is able to see the signal.
           + At 50V and 100V: CH3 is UNABLE to see the signal.


As the clip from Dave I can see there is only one relay for each channel. With this relay the Rigol Ds1054z can choose to by pass the attenuator or not. With my understanding, the function of Attenuator is reduces the power of a signal so if attenuator's CH3 is fail, it will fail on all the small voltage range but the CH3 is not act like it fails on attenuator. So now I'm thinking the problem is on the vertical control position part.




 
 

[beatman]

maybe after so long time the crap psu capacitors gone?what environment contitions was the scope for 9 years?humidity?hot room?

[huu_tri0101]

Thank you for your suggestion but all 3 remain channel are working fine.

[shakalnokturn]

I haven't been round looking for internal photos I have my own repairs to tackle tonight.
If it's displaying normally on low  V/div. settings (Is it or are there other issues there?) and not on high ones I'd be looking at whatever is used for attenuation on the front-end.