Recalibration After Repair - Tektronix 221 Instruction Manual

Corrective Maintenance—221 Service
Circuit Board Replacement.
beyond repair, the entire assembly including all soldered on
components can be replaced. Part numbers are given in the
Mechanical Parts List for either the completely wired or the
unwired board.
NOTE
Even though unwired boards are available w ithout
components, use o f the completely wired replace­
m ent board is recommended due to the large number
o f components mounted on most o f the boards.
Transistor Replacement.
placed unless actually defective. If removed from their
sockets during routine maintenance, return them to their
original sockets. Unnecessary replacement of transistors
may affect the calibration of this instrument. When tran­
sistors are replaced, check the operation of that part o f the
instrument which may be affected.
Replacement transistors should be of the original type or
a direct replacement. Fig. 3-2 shows the lead configuration
o f the transistors used in this instrument. Some plastic case
transistors have lead configurations which do not agree with
those shown here. If a transistor is replaced by a transistor
which is made by a different manufacturer than the original,
check the manufacturer's basing diagram for correct basing.
All transistor sockets in this instrument are wired fo r the
basing used for metal-case transistors.
Rotary Switches. Individual parts of the VO LTS/DIV
and SEC/DIV rotary switches are replaceable. Refer to the
Parts List for the applicable part numbers for replacement
parts.
Troubleshooting Aids
C ircuit board extenders are available to allow trouble­
shooting boards with power applied. Order Tektronix Part
No. 067-0760-00 for Power Supply board extender, and
067-0761-00 for Am plifier board extender
7-2
If a circuit board is damaged
Transistors should not be re­

Recalibration After Repair

After any electrical component has been replaced, the
calibration of that particular circuit should be checked, as
well as the calibration o f other closely related circuits.
Since the power supply affects all circuits, calibration of the
entire instrument should be checked if work has been done
in the supply.
REPACKAGING FOR SHIPM ENT
If the Tektronix instrum ent is to be shipped to a Tektronix
Service Center for service or repair, attach a tag showing:
owner (with address) and the name of an individual at your
firm that can be contacted, complete instrum ent serial
number and a description of the service required.
Save and re-use the package in w hich your instrum ent was
shipped. If the original packaging is unfit for use or not
available, repackage the instrum ent as follows:
1 Obtain a carton of corrugated cardboard having inside
dimensions of no less than six inches more than the
instrum ent dimensions; this w ill allow for cushioning.
Refer to the follow ing table for carton test strength
requirements.
2. Surround the instrum ent w ith polyethylene sheeting to
protect the finish of the instrument.
3. Cushion the instrum ent on all sides by tightly packing
dunnage or urethane foam between carton and instru­
ment, allowing three inches on all sides.
4. Seal carton w ith shipping tape or industrial stapler.
S H IP P IN G C A R T O N TES T S TR E N G TH
Gross W eight (lb)
0-10
10-30
30-120
120-140
140-160
Carton Test Strength (lb)
200
275
375
500
600
REV D, AUG. 1976