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The last page of the "Advanced Users' Manual" for the ARB-704 says this about Technical Assistance:

"If you have any problem with this unit first check the appropriate section of this manual. If the manual does not reference your problem or reading the manual does not solve your problem, call Ameritron at 662-323-8211. We can only help if you have your ARB-704 manual, radio manual, and information about your station available during the call.

We strongly recommend calling Ameritron with any questions, but questions can be mailed directly to Ameritron at 116 Willow Road, Starkville, MS 39759 or Faxed to 662-323-9810. Please be aware that MFJ is a separate facility, and as such does not always offer the best assistance with Ameritron products. Be sure to send a complete description of the problem, explain how this unit is being used, and include a complete description of your station."

I have several ARB-704s of my own, and since one was at hand and I had the necessary jumper cables and ohmmeter at hand, decided to see whether one can determine whether the ARB-704 is, indeed, working with just an ohmmeter. My meter is the moderately-priced Harbor Fright Centech-brand model 61593; your results might differ from mine depending upon your meter.

First, hook up the -704; plug in power, plug in a RCA cable to the Radio jack, then check that when you short the center RCA pin, the front panel Transmit follows your shorting of the center pin. Next, plug your ohmmeter into the jack on the rear panel labeled Amp. If your meter is like mine, I plugged my Red ohmmeter lead into the center pin of the Amp RCA socket and connected the black lead to the shell of the jack. Next, I set the meter to the "Diode Check-Buzzer" position on the Ohms range scale, which, on my meter, is just CCW of the Ohms ranges (it shows a tiny diode symbol to indicate you can check diodes on that switch position). Now, shorting the Radio jack's RCA center pin to ground causes the front panel LED on the '704 to light up, and also causes my ohmmeter to read around 0.63. Switching the ohmmeter to any other resistance range, I have to set it to a high resistance scale such as 200K or higher before it will read again. With the RCA center pin unshorted, the meter reads infinite resistance; shorting the pin makes the meter read some arbitrary resistance (we don't really care what resistance, since we're just trying to find out whether we can even test the ARB-704 with just an ohmmeter).

Now, if you plug your amplifier into the Amp socket on the '704, you should be able to switch it into Transmit as you manually short the center pin of the Radio socket on the -704. If so, move the Radio socket cable back to your FT-3000 and see whether it now works; it should. BUUUUTTTT....

The ARB-704 manual does mention this, on page 8 of the manual: "QSK Radios Some QSK transceivers (mostly early Yaesu's) have a control terminal or jack labeled "Inhibit" or "Linear that has to be grounded on transmit. Consult the radio manual for details on this particular requirement. This connection prevents hot switching of an external power amplifier, and is normally wired to a "handshake" line on a QSK amplifier that tells the radio the amplifier has successfully gone into the transmit mode." It is possible that while you were moving things around, you somehow moved this setting on your radio and it's no longer working the same way.

73,

Steve KJ0XP