Termaline® Semiconductor Load Resistor
10
Coolant Level
Coolant lifetime will vary greatly depending on the operating temperature. For heavy use (full RF power for long
times, high ambient temperature, 50 Hz AC supply), check the coolant every 500 hours. If the load has only had light
duty (fraction of full power, low ambient temperature, 60 Hz AC supply), then coolant inspection may only be
necessary every 2,000 hours.
Note:
Correct any coolant leakage before inspection. (See “Troubleshooting” on page 11)
Inspecting the Coolant
1.
Remove the load resistor. See “Load Resistor” on page 11..
2.
Inspect the coolant for one of the following:
Good:
The coolant is clear, with a faint yellow tinge, and has a slightly sweet smell.
Bad:
The coolant is black with a burnt or acrid smell.
a.
Drain the coolant.
b.
Add about 2.9 gal (11 L) of coolant.
3.
Inspect the coolant level for the following:
With the load still on end, the coolant level should be 4
3
4
to 5 inches (125 mm) below the top surface of
the resistor assembly mounting ring, at ambient temperature.
4.
Add coolant if necessary.
WARNING
Disconnect the unit from all power sources before servicing. The unit may be
energized from multiple sources. The potential for electric shock exists.
CAUTION
Use only Bird coolant, P/N 5-1070, to prevent damage to the load.
