Leader Oscilloscope 8020 service manual

I have a model 8020 Leader Oscilloscope it works but needs to be calibrated. I have been looking all over the internet for a service manual and cannot find one. I just downloaded a manual from this site for Leader LS8050/LS8022 These scopes are similar but not the same and there is no service info in the manual. Any help would be appreciated.
Thank You,

Kevin