Star Micronics Radix User Manual page 189

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Basic Maintenance
175
RepJacing a Fuse
How can you tell when you've blown a fuse? Well, when the
printer won't operate and the power lamp on the control panel
isn't lit, even though you're sure that the power switch is on and
the printer is plugged in - it's likely a blown fuse.
To check the primary fuse, you start by turning the power
switch ofl and unplugging the power cord.
Warning: There is an extreme shock hazard inside Radix. To
avoid serious injury, it is important that the power cord is discon-
nected.
Next, remove the upper case, shown in Figure 14-4, by pulling
off the platen knob.
Caution: Don't twist or turn the platen knob; pull it straight off.
Then remove the fastening screws along the back side. Lift
the back edge of the cover and at the same time, pull it slightly
forward to release the front of the case. Lift it all the way off, being
careful not to pull the wires which connect the cover to the case.
When the case is off, check Figure 13-5 for location of the pri-
mary fuse, which you'll find held by its clamps close to the power
switch. The fuse is a commonly used type, with a metal strip sus-
pended in a glass and metal case. If the strip is broken, the fuse is
blown. Replace this fuse with a 3N125V slow-blow type fuse (Bell
5MT3 or equivalent). Now reassemble Radix and test-run it. If the
printer still isn't working, call on your Radix dealer/service center
for help.
Replacing the Print Head
The dot matrix print head has a remarkably long life, printing
perhaps 100,000,000 characters before it wears out. You'll know
when that happens when the printout is too faint for your taste
even after replacing the ink ribbon or cartridge.
Warning: The print head gets hot during operation, so let it cool
off for awhile, if necessary, to avoid burning your fingers.
To replace the print head, start by turning the power switch
ofi and unplugging the power cord.
Then, in sequence:
1. Remove the front cover and the ribbon cartridge.