Tektronix Type B Plug-In Instruction Manual page 15

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HO W TO ORDER PARTS
Replacement parts are available through your local Tek­
tronix Field Office.
Improvements in Tektronix instruments are incorporated as
soon as available. Therefore, when ordering a replacement
part it is important to supply the part number including any
suffix, instrument type, serial number, plus a modification
number where applicable.
If the part you have ordered has been improved or re­
placed, your local Field O ffice w ill contact you if there is a
change in part number.