Tektronix Applications Expert

See the link below for the 2110 Service manual with the PV and adjust information. https://www.tek.com/en/manual/digital-multimeter/broad-purpose-digital-multimeters-manual-3-keithley-2110-series-5-digit-dual-display-usb-multimeter

Primary Manual can also be found here:
https://www.tek.com/en/manual/digital-multimeter/broad-purpose-digital-multimeters-manual-3-keithley-2110-series-5-digit-dual-display-usb-multimeter

Other links related to the 2110:
https://www.tek.com/en/search?keywords=2110&facets=_templatename%3dManual&sort=desc

The TDS1000 required an option communications module to communicate to a PC. All of these modules are no longer available for sale. If you have a module for the scope please reference the programmers manual for additional details.

Modules:
TDS2CM or TDS2CMA, any version, when used in TDS1000 or TDS2000 Series instruments, any version.

TDS2MEM any version, when used in most TDS1000 or TDS2000 Series instruments (except TDS1001 and TDS2004 models), any version.

SDLC is suppoted on MSO4, MSO5B, MSO6B, not supported on MDO4000

You can find the user manual here: https://www.tek.com/en/oscilloscope/tds1001b-manual/tds1000b-and-tds2000b-series

The best place is this customer's website: https://w140.com/tekwiki/wiki/453

Another one would be VintageTEK:
https://vintagetek.org/

Serial number location could be right under the 543A-4 on front.
Or lower left by Channel one on the 453A-1.
Sorry, not sure for the Rackmount verison.
Very old scopes liek this were usually on the front.
1980's and up were on the back.

The MSO4000 Series oscilloscope uses the P6516 logic probe, part number 071214901.

If by front cover you mean the protective front cover that comes on the unit, note the following: Standing in front of the scope grab in the center (middle) on both sides of the cover pull out then towards you or away from the scope.
If not see the link below to the service manual on tek.com
https://www.tek.com/en/manual/oscilloscope/6-series-mixed-signal-oscilloscope-service-manual-6-series-b-mso-mixed-signal-oscilloscope

Yes, the MDO3 Series is capable of field bandwidth upgrades. Option SUP3 BW2T34 will upgrade your MDO34 from 200MHz to 350MHz. Please reach out to buy@tektronix.com for the most accurate pricing information.

This information can be found on tek.com at this link https://www.tek.com/en/services/repair/warranty-status-search.
12 Months is recommended but it's up to the customers' use case.

You can change the display persistence by double-tapping in the Waveform View area to pull up the display menu. There are a couple options for persistence length, including variable and infinite. Variable persistence allows you to input the amount of time waveforms will collect on the screen. If you want to save a waveform file with a similar view, you can use the Envelope acquisition mode. This mode shows the extremes in variations over several waveform acquisitions. This mode can be found in the Acquisition menu.

The user manual is a pretty good place to start learning about the MSO68B: https://www.tek.com/en/manual/oscilloscope/456-series-mso-help-5-series-mso.