wa9btv
2013-04-23 06:19:46 UTC
Hi ALL,
I just purchased a TS-790 and I thought is was a great deal until I got it home and its not working. I opened it up and the radio looks as if it were never used both outside and in. The radio does not have a scratch on it.....it looks like new out of the box.
The internal fan does not even have a speck of dust on it like the radio was not used. Its a later version with a serial number of 83XXX.
Upon applying power I noticed that it is drawing some current and the 2M band is transmitting low power with no mic attached and no transmit button being pushed? If I change the 2M frequency either up or down the power will vary from about 500mw to about 3 watts. The RF power out setting control when varied does not affect the output. When a mike is hooked up and TX is pressed it does not have any power out more than the three watts.
2. The main band side is not working in terns of receiving when either 144MHZ or 440MHZ is selected as well. It is totally dead. I injected a 1uv signal into the antenna jack with no indication or noise or otherwise comes from the speaker. No matter where the volume setting or squelch setting no noise is heard from the speaker except the beeps from changing functions or pressing buttons on the radio.
The frequency dial seems to work and will changes the frequency for the respective band when adjusted. the digital dial readout for frequency appears to work and the display is working fine. I checked the voltage on the memory back up battery and it was good at 3.1VDC.
I did confirm the radio it does TX a low power RF signal with good audio. I could hear my transmission from the TS-790 on an HT in the next room. But cannot hear the HT transmission on the TS-790. All of these tests being performed on the main VFO side.
3. Now on the sub band side I can hear either 144mhz and 440 MHz with full meter deflection on the TS-790. I could also hear both the 2m and 440MHz signal in the HT but again no power out just very weak output....almost like just a driver is working.
4. I took some voltage measurements of the driver and final output modules and they appear to be within normal limits of the service manual.
It really a bewildering issue, because of how the radio is acting.
I am not sure of anyone has any experience with these radios, as I do not and if anyone with experience can make a suggestion I where I might look for something that is in common with all of these issues that would be greatly appreciated.
73,
Paul
WA9BTV
I just purchased a TS-790 and I thought is was a great deal until I got it home and its not working. I opened it up and the radio looks as if it were never used both outside and in. The radio does not have a scratch on it.....it looks like new out of the box.
The internal fan does not even have a speck of dust on it like the radio was not used. Its a later version with a serial number of 83XXX.
Upon applying power I noticed that it is drawing some current and the 2M band is transmitting low power with no mic attached and no transmit button being pushed? If I change the 2M frequency either up or down the power will vary from about 500mw to about 3 watts. The RF power out setting control when varied does not affect the output. When a mike is hooked up and TX is pressed it does not have any power out more than the three watts.
2. The main band side is not working in terns of receiving when either 144MHZ or 440MHZ is selected as well. It is totally dead. I injected a 1uv signal into the antenna jack with no indication or noise or otherwise comes from the speaker. No matter where the volume setting or squelch setting no noise is heard from the speaker except the beeps from changing functions or pressing buttons on the radio.
The frequency dial seems to work and will changes the frequency for the respective band when adjusted. the digital dial readout for frequency appears to work and the display is working fine. I checked the voltage on the memory back up battery and it was good at 3.1VDC.
I did confirm the radio it does TX a low power RF signal with good audio. I could hear my transmission from the TS-790 on an HT in the next room. But cannot hear the HT transmission on the TS-790. All of these tests being performed on the main VFO side.
3. Now on the sub band side I can hear either 144mhz and 440 MHz with full meter deflection on the TS-790. I could also hear both the 2m and 440MHz signal in the HT but again no power out just very weak output....almost like just a driver is working.
4. I took some voltage measurements of the driver and final output modules and they appear to be within normal limits of the service manual.
It really a bewildering issue, because of how the radio is acting.
I am not sure of anyone has any experience with these radios, as I do not and if anyone with experience can make a suggestion I where I might look for something that is in common with all of these issues that would be greatly appreciated.
From my unexperienced guess it seems for sure that something is going on with the main band and the sub band appears to be working. Also why the 2m radio portion is always in TX is a mystery??? The 440 side only TX when the mike is attached to the radio and the TX button pressed....which is normal and you'd expect that.
Thanks for any help73,
Paul
WA9BTV