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


TS-940S PLL Unlock                 4-8-86


Reports of a PLL unlock on the lower frequencies may be due to low VCO
levels.  The following change will increase the VCO level and should
prevent reoccurrance of this symptom.

Part Required

C168           change to 15 pF 50v (CC45SL1H150J)

Procedure:
1.   On the RF Unit (X44-1660-00) change C168 from a 33 pF capacitor to a
15pf 50v capacitor.
2.   Readjust the VCO BPF (RF unit L74-76) according to the instructions
contained in the TS-940S Service Manual.

This change is applicable to serial numbers prior to 606XXXX.

Time required for this modification is 1 hour or less.

(c) 121589TKC


TS-940S PLL Unlock                 10-18-85


Some users of the TS-940S have reported a blanking of the display
accompanied by a loss of transmit and receive.  Re-adjustment of the PLL
unit will correct this tendency.

PROCEDURE:

On the PLL unit

1.   Set the dial frequency for approximately 1.8 MHz (inside the band)
2.   Using an RF probe at TP5 adjust L22, L23, and L24 for a maximum
reading on the meter.  You should see approximately 250mv.
3.   Adjustment of L24 will produce the greatest change, which may be up to
a 90 degree adjustment from its present position.

Time required for this modification is 1/2 hour or less.
CLM
(c) 121589TKC
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