ENABLE TR-7 TO TRANSMIT 1.5 - 30 MHz without AUX-7
Two methods:
Click to enlarge
Picture: JM CHERRY
- Unplug all interconnecting cables from the TR-7.
- Place the radio upside down, with the front panel facing you.
- Remove the Bottom cover plate by removing ten screws and sliding the plate to the rear.
- Refer to the attached photograph and figures and identify connector pin row 1, 2 and 3 on the front right-hand comer of the parent board.
- Carefully identify pin 11 in rows 2 and 3.
- Note that a foil trace connects pin 11 in rows 2 and 3. Using a sharp knife cut this trace in two. Use caution, and do not disturb any other circuits.
- Reinstall the bottom cover plate and reconnect all associated station equipment.
About This modification, I received
a very Interesting mail from:
Bart Pulverman, WB6WUW
8434 Periwinkle Drive
Buena Park, CA 90620-2119
I noticed a link on your home page titled "TR-7: How to transmit 1.5 - 30 MHz with or without AUX-7?" That method, which I have seen before, requires cutting a trace on the motherboard. That results in unnecessary permanent damage to the motherboard (from the perspective of maintaining a pristine, stock radio) and there is always the possibility of cutting the wrong trace.
Although I have an AUX-7 board on
my TR-7, I did not want to pay $52 each for the three programmed chips
required to add transmit capability when the WARC bands (30, 17 and 12 meters)
were reassigned to hams in the mid 80's. I found that by removing Q201 (2N3904
transistor) from the Digital Control Board (see Fig 2), that the
"Transmitter Enable" signal was permanently forced to the enabled
state. This results in the same continuous coverage without cutting
traces. I have saved the transistor.
If I ever want to delegate my TR-7 to museum status, all I need to do is solder
Q201 back on the board. The method described on your web page cuts the
"Transmitter Enable" trace on the mother board which is electrically
equivalent, but destructive.µ
Click to enlarge
The step-by-step instructions
are:
1. Remove the TR-7 top cabinet cover.
2. Remove the DR-7 Board.
3. Remove the board shield under the DR-7.
4. Remove the Digital Control Board.
5. Carefully unsolder and remove Q201 from the Digital Control Board.
6. Replace the Digital Control Board.
7. Replace the board shield.
8. Replace the DR-7 Board.
9. Replace the TR-7 top cabinet cover.
CAUTION: With "Transmitter Enable" always in the enabled state,
the user is no longer protected from inadvertently transmitting outside the
amateur bands.
Bart Pulverman, WB6WUW