4CX250 Series

The 4CX250B/7203 has a maximum plate dissipation rating of 250 watts and a maximum input power rating of 500 watts. The 4CX250B/7203 is designed to operate with a heater voltage of 6.0 volts. 

The 4CX250BC/8957 is especially recommended as a premium quality replacement for the 4CX250B/7203, in applications where long life and consistent performance are of prime concern and the closer heater voltage tolerance and increased cathode warmup time are acceptable.

The 4CX250B/M is a ceramic/metal, forced-air cooled external-anode tetrode with a maximum anode dissipation rating of 250 Watts. The 4CX250B/M is intended for use in applications where tight control of electrical specifications is required and replaces the 4CX250B in all applications. This tube utilizes a ruggedized internal structure and utilizes a welded anode cap for improved reliability.

The 4CX250FG/8621 has a maximum plate dissipation rating of 250 watts and a maximum input power rating of 500 watts. The 4CX250FG/8621 is designed for operation at a heater voltage of 26.5 volts.

The 4CX250R/7580W is designed specifically for use in Class AB1 linear amplifiers where shock and/or vibration preclude the use of non-ruggedized tube types. The 4CX250R/7580W will replace the 4CX250B in equipments where the range of bias adjustment will tolerate this higher purveyance tube and where tuning range can compensate for the small differences in input and output capacitances. The 4CX250R/7580W will deliver more output in most linear amplifiers which presently employ the 4CX250B.

GRADING OF TUBES

RF PARTS COMPANY provides full testing and matching services to our customers in order to assure they will receive full value in their investment.

NEW TUBES TESTING AND MATCHING.

All new tubes we buy to sell under our Name, will receive our Standard Factory Testing at the RF PARTS facility before acceptance from the manufacturer. Tubes are tested for Transconductance, Filament Condition, Shorts, and Gas. After full testing, the tubes may be marked with either the RF PARTS or TAYLOR labeling.   The next step is to make electrically matched sets for the customer.  Any that fail our tests will be returned to the factory.  Each tube carries a Limited Transmitter Tube warranty.  Warranty period varies by tube number.

RF PARTS has a limited number of like new tubes with older date codes.  All tubes receive the Standard Factory Test for each tube type.  We still have U.S. made EIMAC and AMPEREX tubes available in limited quantities. 

TUBE TESTING AND GRADING.

After our full electrical testing, tubes will be cleaned, graded, and re-boxed for sale.  Following is a description of our grading process:

NOS – NEW OLD STOCK

NOS:  A like new tube which tests at 100%.  Silver plated tubes may exhibit some silver tarnish (which does not detract from performance).  Some tubes may show faint marks from the socket in our testing equipment.  All NOS tubes carry the RF PARTS Standard Limited Warranty covering workmanship and materials for 90 days.

NOS-1:  A like new tube, testing at 95-100%.   Tube may have some cosmetic blemishes, scratches, light tarnish, etc.  90 Day Limited Warranty.

NOS-2:  Full testing as we do for our NOS & NOS-1 Tubes (95%-100%), but having more surface tarnish, scratches, etc.  Still a perfectly good tube electrically.  90 Day Limited Warranty.

PULLOUT TUBES – CLEAN TUBES REMOVED FROM EQUIPMENT

P:  This is a “Good Used Tube” or “Pull”.  Some are removed from New or Reconditioned Military or Commercial Equipment.  This tube receives the Full RF PARTS Testing, and is electrically similar to our NOS-1 tube at 95%-100%.  There may be some scratches or discoloration indicating that the tube had been in a socket, etc.   90 Day Limited Warranty.

P-1:  Similar to our –P selection, but may have more cosmetic or older date codes.  Full RF PARTS Testing, and is electrically similar as our NOS-1 tube at 95%-100%.   90 Day Limited Warranty.

P-2:  Similar to the –P tube, but more obviously used due to cosmetic issues.  Tests in the 90%-100% range. Plenty of life left.   90 Days limited Warranty.