Tektronix WFM91 Stereo System User Manual


 
Maintenance
6–4
WFM 90 and WFM 91 Service Manual
After cleaning, carefully check the instrument for defective connections,
damaged parts, and improperly seated transistors or integrated circuits. The
remedy for most visible defects is obvious; however, if heat-damaged parts are
discovered, determine the cause of overheating before replacing the damaged
part.
Periodic checks of the transistors and integrated circuits are not recommended.
The best measure of performance is the actual operation of the component in the
circuit.
Instrument performance should be checked after each 2000 hours of operation or
every 12 months. This will help to ensure maximum performance and assist in
locating defects that may not be apparent during regular operation. Performance
Verification and Adjustment Procedures are included in this manual.
After Repair Adjustments
It is recommended that you perform the Adjustment Procedures starting on
page 5–1 whenever you have removed the Top or Bottom cover during the
service of this instrument.
Repackaging Instructions
Use the following instructions to prepare your instrument for shipment to a
Tektronix, Inc., Service Center:
1. Attach a tag to the instrument showing: the owner, complete address and
phone number of someone at your firm who can be contacted, the instrument
serial number, and a description of the required service.
2. Package the instrument in the original packaging materials. If the original
packaging materials are not available, follow these directions:
a. Obtain a carton of corrugated cardboard having inside dimensions six or
more inches greater than the dimensions of the instrument. Use a
shipping carton that has a test strength of at least 250 pounds (113.5 kg).
b. Place the instrument in its carrying pouch or surround the instrument
with a protective bag.
c. Pack dunnage or urethane foam between the instrument and the carton. If
using Styrofoam kernels, overfill the box and compress the kernels by
closing the lid. There should be three inches of tightly packed cushion-
ing on all sides of the instrument.
3. Seal the carton with shipping tape, industrial stapler, or both.
Visual Inspection
Performance Verification
and Readjustments