Texas Star DX667V, Relay bad, or parts that trigger the relay?

[skiman1]

Texas Star DX667V, all Toshiba's. It takes near a 2w deadkey to key it up and by then the amp deadkey out is 180w, so using the variable to tame it back to 120'ish and the swing is the expected 500w PEP. I was told it could be the relay is dirty, so I cleaned it, still the same thing. My question is could it be the relay, or parts that drive the relay?

I tried this, keyed the radio with 1w, didn't trigger it, TAPPED the relay and voila, it kicks in and with the expected 120'ish out without turning down the variable. I was able to repeat this several times. To me its more than likely a mechanical issue with the relay than an electrical one.

Has anyone else had this issue? I ordered a replacement relay and will be changing it this week. Thanks!

 

[Shockwave]

More than likely, the capacitor, RF diode or transistor in the keying circuit. I doubt it's the relay. You could measure the voltage being applied to the relay coil, by checking it across the black diode that is in parallel with that coil. If it's under 10.5 volts with the microphone keyed, and the relay has not pulled in, it is the circuit.

 

[skiman1]

Thanks Shockwave, I'll check it out. So C4, D1 and Q1?

 

[skiman1]

More than likely, the capacitor, RF diode or transistor in the keying circuit. I doubt it's the relay. You could measure the voltage being applied to the relay coil, by checking it across the black diode that is in parallel with that coil. If it's under 10.5 volts with the microphone keyed, and the relay has not pulled in, it is the circuit.

With keying the mic and relay not engaged, it was a little over 5v, when the relay was activated, it was a little over 2v.

Not sure it mattered, but this was with the variable turned down and the Dial-A-Watt depressed, so there would be no output when it keyed up.

 

[skiman1]

More than likely, the capacitor, RF diode or transistor in the keying circuit.

Shockwave, was the cap you were referring to C2? The SSB delay is fine so I would guess that C4, the 1000uF, is still good.

 

[Shockwave]

The capacitor I was thinking about will look more like C1 C2 or C3. It's the one that feeds our RF into the keying transistor. Also check L1 and L2 to make sure they are not burnt looking. In this case, D1 will not be burnt out but it is the diode you could measure across to check the coil voltage.

 

[Shockwave]

With keying the mic and relay not engaged, it was a little over 5v, when the relay was activated, it was a little over 2v.

Not sure it mattered, but this was with the variable turned down and the Dial-A-Watt depressed, so there would be no output when it keyed up.

This rules out the relay and makes the circuit suspect. I remember something about if L1 or L2 were overheated, it reduces the sensitivity of the RF keying circuit.

 

[Robalo]

Or maybe this under the relay that was the problem on mine

 

[Shockwave]

Or maybe this under the relay that was the problem on my

I wanted to be an optimist, before having to consider problems under the board.

 

[skiman1]

Thanks guys, LOTS to consider here, sounds like I need a pro to take care of this, way beyond my pay grade.