Here goes some hints for modifying the TS-790 for 9600 bps.
... I am composing a mod file for 9600 bps to upload to my webpage... but it is not complete yet. I remembered it could be useful so i decided to send it to you (while not completed).
Follow the instructions on the mod files to find both discriminators (Main and Sub) and the modulator.
Instead of attaching only one discriminator, I used a small relay driven by a BC547 transistor, attached to the 144ATT switch (that otherwise is useless on the front panel of the TS790) to choose between terrestrial and sats packet!
Also, instead of soldering the RG174 directly to the ACC4, there are two pins just nearby ACC2 (you'll see two holes with solder) that are connected to pins 3 and 5. You can confirm it using a multimeter. It is easier and cleaner to use them instead of soldering it directly to ACC4.
You have three choices for attaching the ground braid of RG174 - please do it only from one side to prevent ground loops! Choices are: attach both braids (the one coming from the discriminator and the other from the modulator) to a ground lug mounted on the large aluminum heat sink near ACC2 and ACC4, attach to the DC-DC converter that is right near ACC4, or attach to the other end, that is to the other pins of J31 for the modulator and to pins 15 of MC3357 (if i am not mistaken now - you have to check with your multimeter).
And this is now a 9600 ready rig (hi!hi!hi!)!!!
The other thing I did not try yet... for 9600 operation you have to disconnect the mic and reduce mic volume to the minimum (and I like things to be just switch and play!)... I am connecting also the 1200 modem to ACC2 so i will use (i guess now is pin 13 of ACC2 - it comes in the manual) it to switch off the mic!! When you turn on one of the modems, mic is automatically switched off by applying a signal to pin 13 - as I did not try it yet, you have to try it or wait for me to try.
73,
Paulo, CT1EFS
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