TS-930 transciever mods ======================= Part 1 of 2 The following changes are quite simple and do not require the addition of any switches. NOTE: In the operator's manual supplied with the 930, there is an error on one of the drawings. On the upper left corner of the DIGITAL UNIT schematic locate connector 8. The lead designations are as follows (note that some of the designations do not appear on this sheet so you can add them to the drawing): Pin Desig. 1 100 2 MU 3 SCN 4 M2 5 MIN 6 FSK 7 B2 8 FT On the main drawing, called SCHEMATIC DIAGRAM, the pin numbers shown on connector 8 are reversed from the way they are numbered on the DIGITAL UNIT schematic. In the following changes, I am assuming that the numbering on the DIGITAL UNIT sheet is correct. In any event, it will be obvious which end is which since the end pin is vacant. CHANGES ~~~~~~~ 1) The resolution of the main tuning digital readout can be increased from 100Hz to 10Hz. No digits are lost since the readout has the extra digit for this purpose. This change is accomplished by grounding pin 1 of connector 8 on the DIGITAL UNIT. 2) The tuning rate is 10kHz per revolution of the main tuning knob. The tuning rate can be changed to kHz per revolution by cutting one end of diode D-13 on the DIGITAL UNIT. (Note that the black marks on the tuning knob itself are exactly 500Hz apart. The knob can be "corrected" by tuning in an exact frequency, for example 10,000.00kHz, pressing the DIAL LOCK switch, then turning the knob to line up a black line. As long as you don't spin the dial too fast, it will track nicely from one end to the other. With the slow rate modification, the dial increments become 250Hz per division). You may desire to switch this reduced tuning rate on and off. For example, you can select the new rate on just VFO B by using an unused section of the "FUNCTION" switch. Another possibility is to use the display "DIM" switch. 3) There are an additional 8 memories available. These can be obtained by grounding pin 5 of connector 7 on the DIGITAL UNIT. (This lead is designated "M3"). The 8 additional memories can be selected by using an unused contact on the "FUNCTION" switch. 4) Each group of 8 memories can be scanned at a rate of about 1 per second. Unlike a normal scanner, The unit will not stop scanning when a signal is present, but it is a good way to search favorite frequencies for activity. A method of turning on the scan function without affecting normal switch functions would be to wire the unused section of the DIAL LOCK switch in series with the unused section of the METER switch (meter switch in the "VC" position). 5) A handy option is to be able to momentarily unlock one VFO when the DIAL LOCK is on. This can be useful during split frequency operation when you want to keep the receive vfo locked (the DX station's xmit freq), yet quickly QSY to the frequency he is listening to with your transmit VFO. This change can be made by wiring one lead from the DIAL LOCK switch in series with extra normally closed contacts of the "T-F" switch. 6) This change permits automatic disabling of a linear amplifier during full break-in cw operation. This is desirable since the relays in a linear cannot properly follow each keyed character element. This change should also be done if AMTOR operation is contemplated. Assuming that your 930 has the aux. relay board in it, merely wire the +28 volt lead to the relay coil in series with the extra contacts of the "FULL-SEMI" switch. 7) For AMTOR operation, the T-R switching speed must be increased. Two suggested changes are to remove C-500 (4.7uF) on the SIGNAL BOARD (located top center near connector 30), and to ground the junction of R-476 / Q-100. 8) In early units, the WARC band transmit was not enabled. If this is the case, solder a jumper from pin 12 of IC-23 to ground on the DIGITAL UNIT. (Ground can be obtained at pin 8 of IC-24). 9) Transmit can be enabled on all frequencies between 1.5 and 30MHz for MARS and transverter use by adding two jumpers on the DIGITAL UNIT: Connect pin 9 of IC-11 to pin 12 of IC-21. Connect pin 9 of IC-12 to pin 12 of IC-22. Cont'd in part 2