Filter    Part No.       -6db Bandwidth -70db Bandwidth Retail
CFK-455F  L72-0304-05    +/- 6 kHz      +/- 12 kHz       33.50
CFK-455G  (CFK-455G)*    +/- 4 kHz      +/- 10 kHz       33.50

* Not original part.  No computer part number.

Location: TR-9200, RX unit X55-1270-10 part, L10
          TR-9000, RX unit X55-1260-11 part, CF1

Complainte of FMing in SSB, or CW chirp may be eliminated by minor changes to the TX mixer circuit.

On the TX unit X56-1370-10, perform the following changes:

1. Cut the LT foil path.
2. Install a 47 ohm resistor on the foil side of the PCB.
3. Remove R27, 3.3 Kohm and delete.
4. Jumper the cut foil.
5. Install a 2.2 Kohm resistor from Q12 Collector to the modified LT foil on the foil side of the PCB.

Pulse noise heard during SSB transmission may be reduced or eliminated by adding one capacitor to the TX unit.

On the TX unit X56-1307-10 add a 22uF 16V radial lead cap to the PMB line, as illustrated, on the foil side of the PCB.
No adjustment are necessary.

Distorted sideband transmission may have one of two causes. If normal alignment docs cure the problem, distortion or poor carrier suppression may be improved by rercuting two leads in the wire harness.

Perform these initial checks first:

1. On early units, ascertain that R74, 47 ohm is on the TX unit X55-1370-10 between connector 33, the LT line, and R27, 2,2 Kohm (vicinity of Q5, Q6), and that R27 is 2.2 Kohm. (Service Bulletin #824).
2. Verify TR-900 Service Manual alignments, General section steps 4 (PLL), and 5 (HET frequency alignment).
3. TX section, steps #4 (power adjustment), 9 (SSB mic gain), 10 (carrier point) & 11 (carrier suppression).

Procedure:

1. Remove the bottom cover and unplug the speaker.
2. With the radio upside down and facing forward, locate connectors 8 and 10 at the front of the RX unit X55-1260-00. Connector #8, pin 3 (violet) is the -6V DC line from the TX unit, connector # 31, pin 1. Connector # 10, pins 7 (signal) and 8 (ground) (green coaxial cable) is the MS pins 5 (sig) and 4 (gnd).
3. Carefully cut the cable ties (without cutting any leads) securing these two lines in the wire harness which runs to the left, around the upright Control unit, and then right behind the front panel ad far as the Mode switch.
4. Carefully unplug each of these connectors by gripping the connector housing with a long-nosed plier.
5. Extract the terminal from the housing by depressing the locking tab and simultaneously withdrawing the lead with terminal. (See illustration below).
6. Reroute these two lines from the behind the Mode switch, between the chassis and control unit, then left to their original connectors. Reinstall the terminals in their original positions in the connector housing.
7. Coil the excess of each lead and secure with cable ties. Retie the harness behind the front panel, along the left of the chassis, and back behind the control unit.
8. Readjust carrier suppression. Mod SW:USB, Mic terminal terminated with 470 ohm. On the RX unit, alternately adjust TC1 & VR6 for minimum output at 145 MHz. Carrier should be at least -40dB down.
9. Work is complete. Replace the bottom cover.

PLL noise or unlock at high temperature may be cured by changing a mixer feed point in the PLL.

Measure TP3 on the PLL unit. If greater then 0.5V RMS signal is available, this change will not be required.
If less than this level is present proceed.

On the PLL unit X50-1620-00 at Q13:

1. Remove and delete C23.
2. Connect Q13 emitter to L5 "hot" (original C23 take-off.)
3. Realign L5, 6, 7 for at least 0.5V RMS at TP3.

Note: Installation time for this procedure is ½ hour or less.

Alignment note: To align L6 & 7, first position the slugs flush with the tops of the coils, then alternately adjust these two coils for maximum output at the first peak into the coil (fundamental frequency). Then align L5 for maximum.