TA Instruments TGA 2050, Operator'S Manual

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TA I
NSTRUMENTS
TGA 2050 5–13
Fuse 1 is in the circuit between the main electri-
cal input and the POWER switch. All power for
internal operations and instrument functions,
except heater power, passes through this fuse. If
this fuse blows, you will get no response from
the instrument when you attempt to turn it on.
Fuse 2 protects the heater coils in the furnace.
Because fuse 2 does not power the internal
logic, you may not know that this fuse is blown
until you try to heat a sample; the TGA passes
the confidence test with fuse 2 open.
Fuse 2 is always checked at the beginning of a
method. Power supplied by this circuit is
switched by a computer-controlled relay. If fuse
F2 is open at the start of a run, error 73 “No
heater power at startup” is displayed, then the
run is terminated.
Power Failures
A power failure caused by a temporary drop in
line voltage results in one of two responses by
the TGA instrument:
• If the drop is fairly large and of long
duration (20 milliseconds or more), the
system will reset and go into its power-up
sequence when power resumes.
• If the drop is small or of short duration, the
system may halt. The instrument will not
restart until it is reset. To reset, press the
Reset button on the TGA’s back panel.
The TGA is designed for a nominal line voltage
of 115 volts AC (+ 10%), 50 or 60 Hz. It should
not be operated outside this range. Low line
voltage may result in poor instrument operation;
high line voltage may damage the instrument.
Diagnosing Power Problems