Installation
Overview
The basic upgrade kit adds to a Ten-Tec 1254 shortwave radio receiver finer step frequency tuning, more memory channels, new radio features, and removal of the need for a backup battery. It does this by replacing the radio's PIC processor with new firmware in a new Cypress processor mounted on a daughter board to fit the radios's existing processor socket. With the addition of an auxiliary circuit board, cables, and a new aluminum rear panel a full kit can also add line level audio output, and a computer CAT control interface. The computer interface can be ordered as either an RS-232 or mini-USB connection.
The upgrade kit does not change the radio as supplied by Ten-Tec in it's construction or alignment procedures. The alignment can be done with either processor.
1254 Upgrade Kit Contents
- Precision laser cut aluminum rear panel with mounted auxiliary interface board, 3.5mm line level output jack, computer communications connector with transmit and receive status LEDs, and AGC level input connector.
- Cypress processor mounted on a daughter board with components for analog and digital interfaces.
- Shielded analog audio input coax to connect the processor board to the radio's main board.
- Optional Ten-Tec 1254 display board mounted auxiliary LED. (see note 1)
- Ribbon cable to connect the processor board to the auxiliary interface board.
- AGC tie in wire and connector from the radio's main board to the auxiliary board.
1254 Basic Upgrade Kit Contents
- Cypress processor mounted on a daughter board with components for the extra analog and digital interfaces unpopulated.
- Optional Ten-Tec 1254 display board mounted auxiliary LED. (see note 1)
Upgrade Kit Installations
The processor daughter board is pre-assembled and ready to snap in place on the radio's main circuit board. All that is required is to carefully remove the PIC processor, if already installed, then line up the pins 1 to 1 from the main board's processor socket to the daughter board header and press the new board in place. (The section of the daughter board that holds the JP1 connector must be pointed to the back of the radio.) Note: do not use the 9 Volt that was required for the original PIC processor supplied from Ten-Tec.
For a basic kit this completes the installation.
The full kit adds to the upgrade an auxiliary interface circuit board mounted to a new rear aluminum panel. To install the new assembly first remove the speaker assembly from the radio by removing the four flat head black screws and unplugging the speaker wire connector from the main radio board. The original rear aluminum panel on the radio is then removed. It will be replaced by the auxiliary board and panel assembly. Before screwing in the new rear panel insert and lock in the flex cable feeding it under the auxiliary board and behind the main radio board, The blue part of the flex cable is inserted facing the moveable part of the flex cable connector.
Board Cable Connections
The processor daughter board has a vertical connector for a six wire flex cable which runs to the new rear aluminum panel assembly. A coax which plugs into connector X1 on the opposite side of the board is used to tie to the audio input on the main radio board. An unpopulated .100" header is on the bottom of the daughter board used only for programming the processor.
- JP1 INTERBOARD Connector for inter-connecting to the rear panel mounted auxiliary board.
- X1 AUDIO Coax for the low level audio input from the radio's main board.
The auxiliary board has a six wire flex connector for the cable to the processor daughter board, and a single wire on a two pin connector.
AGC Pickup Connection
The AGC voltage is used to determine the signal strength which is read over the computer control interface. Use the yellow wire with the two pin JST connector. Plug it into the auxiliary board's two pin receptacle. Feed the wire around the back of the radio to the top side of the main radio board. Solder the end of the wire to resistor R66, either side.
Audio Pickup Connection
The audio input to the daughter board is picked up from the input pin of the radio's
audio power amplifier. To access this point the shielded audio cable must be
plugged into X1 on the daughter board and threaded through to the bottom side of
the radio's main board.
There is a row of what looks like 10 pads in a row where the amp is soldered on to the radio's main board. Note only 9 of these pads go to the pins of the amp. Observe the picture of the bottom of the board around the speaker connector and the notch for the tuning encoder. Pin 8 is the solder point for the signal, center conductor, of the shielded cable. Note that it is easier to solder to the pad just behind Pin 8.
Run the coax so as to not let it's connector twist left or right shorting any of the components on the daughter board.
Daughter Board to Auxiliary Board and Panel Assembly Interconnect Cable
The six wire flex cable is used to connect the daughter board and auxiliary board together. Plug either end of the cable to their respective receptacles on both boards. Run the cable from one side of the board to the other between the gap of the main radio board and where the rear aluminum panel mounts.
This completes the full upgrade.
Note 1: There is also an optional additional LED supplied in the kit that can be installed in an existing, but unused location on the display board.
Display Circuit Board Auxiliary LED
This step is optional. It is more easily done during the radio assembly. Two green LEDs, D5 and D6, are provided with the Ten-Tec kit to indicate the receiver mode, either AM or SSB. The stock display board has three positions for LEDs though, with an unused and unmarked location available for a LED between the two designated for use in the kit's instructions. The upgrade makes use of this unused board mounting location. Take the provided new LED and place it in the two holes of the unused position. Mount it with the same polarity orientation as the other two, and at the same height off the circuit board. The firmware controls the illumination of this LED if present to provide additional information about the state for the radio.
