Comtech EF Data SDR-54A - Manual (Page 33)

SDR-54A Satellite Demodulator Revision 4
Operation MN/SDR54A.IOM
4.3 Cooling Fan
The SDR-54A uses a 12VDC fan to provide adequate cooling of the unit. Be sure to
provide sufficient clearance (1 inch minimum) on the back and sides of the unit for
proper ventilation.
Units manufactured prior to May 1, 2002 incorporated a temperature control circuit for
fan operation. This control circuit would activate fan operation when the unit reached a
certain temperature and then shut the fan off when the unit cooled. Units built after May
1, 2002 have the control circuit removed thus allowing constant fan operation, resulting
in a more stable internal temperature. Any units sent in to CEFD for repair also will have
the control circuit bypassed.
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