Elenco 30MHz Dual Trace - Manual (Page 63)

Maintenance
OSCILLOSCOPE INSTRUCTION MANUAL
60
A following instruction are for use by qualified service personnel only. To avoid
electrical shock, do not perform any servicing other contained in the operation
instructions unless you are qualified to do so.
High voltage up to 1,250 volts is present when cover is removed and the unit is
operating. Remember that high voltage may be retained indefinitely on high voltage
capacitors. Also remember that ac line voltage is present on line voltage input circuits
any time the instrument is plugged into an ac outlet, even if turned off. Unplug the
oscilloscope and discharge high voltage capacitors before performing service
procedures
FUSE REPLACEMENT
If the fuse blows, the “ON” indicator will not light and the oscilloscope will not operate.
The fuse should not normally open unless a problem has developed in the unit. Try to
determine and correct the cause of the blown fuse, then replace only with the correct
value fuse. For 115V line voltage operation, use a 800 mA, 250V fuse. For 230V line
voltage operation, use a 600mA, 250V fuse. The fuse is located on the rear panel
adjacent to the power cord receptacle.
Remove the fuseholder assembly as follows:
1. Unplug the power cord from rear of scope.
2. Insert a small screwdriver in fuseholder slot (located between fuseholder and
receptacle). Pry fuseholder away from receptacle.
3. When reinstalling fuseholder, be sure that the fuse is installed so that the correct
line voltage is selected (see LINE VOLTAGE SELECTION).
LINE VOLTAGE SELECTION
To select the desired line voltage, simply insert the fuse and fuse holder so that the
appropriate voltage is at the top (pointed to by the arrow). Be sure to use the proper
value fuse (see label on rear panel.)
PERIODIC ADJUSTMENTS
Prove compensation and trace rotation adjustments should be checked periodically
and adjusted if required. These Procedures are given below.
Probe Compensation
1. Connect probes to CH 1 to CH 2 input jacks. Perform procedure for each probe,
one probe at a time.
WARNIN G!