Servicing Precautions

CAUTION: Before servicing instruments covered by this service manual, its supplements, and addendum, please read and follow the SAFETY PRECAUTIONS of this manual.

NOTE: If unforeseen circumstances create conflict between the following servicing precautions and any

of the safety precautions on page 1 of this manual, always follow the safety precautions. Remember: Safety First.

◆General Servicing Precautions

1.Always unplug the AC power cord from the AC power source before:

a. Removing or reinstalling any component, circuit board, module, or any other instrument assembly.

b.Disconnecting or reconnecting any electrical plug or other electrical connection.

c.Connecting a test substitute in parallel with an electrolytic capacitor in the instrument.

CAUTION: A wrong part substitution or incorrect polarity installation of electrolytic capacitors may result in a explosion.

d. Discharging the picture tube anode.

2.Test high voltage only by measuring it with an appropriate high voltage meter or other voltage measuring device (DVM, FETVOM. etc.) equipped with a suitable high voltage probe. Do not test high voltage by “drawing an arc”.

3.Discharge the picture tube anode only by: (a) first connecting one end of an insulated clip lead to the degaussing or line grounding system shield at the point where the picture tube socket ground lead is connected, and then (b) touching the other end of the insulated clip lead to the picture tube anode button, using an insulating handle to avoid personal contact with high voltage.

4.Do not any spray chemicals on or near this instrument, or any of its assemblies.

5.Unless otherwise specified in this service manual, only clean electrical contacts by applying the following mixture to the contacts with a pipe cleaner, cotton-tipped stick, or comparable nonabrasive applicator: 10% (by volume) Aceton and 90% (by volume) isopropyl alchohol (90%-99% strength).

CAUTION: This is a flammable mixture. Unless specified in this service manual, lubrication of contacts is not required.

6.Do not apply AC power to this instrument and/or any other of its electrical assemblies unless all the solid-state device heat sinks are correctly installed.

7.Always connect the test instrument ground lead to the appropriate instrument chassis ground before connecting the test instrument positive lead. Always remove the test instrument ground lead last.

8.Only use the test fixtures specified in this service manual with this instrument.