SB-913 TS-940S Signal to Noise Ratio Improvement 8-26-86 The following changes will reduce the tendency of the Zener Diode in the Noise Blanker circuit to cause an increase in the ambient noise level. This change ensures that no current flows thru this diode in the normal receive position. Parts Required: 560 ohm 1/4 watt resistor Procedure: On the IF UNIT X48-1430-00 change R23 from 330 ohms to 560 ohms. This change will be incorporated in all models beginning with serial number 603XXXX. Time required for this modification is 1 hour or less. (c) 121589TKC