RM kl 500 relay chattering on ssb

[prettypolly]

I've got a silly problem with my RM kl 500 chattering on ssb ,,am FM is fine full power 200 watts plus but ,it's chattering like a set of false teeth on ssb when trying to modulate I've read around the net some are saying it's c3 ceramic disc capacitor the version of the board is rev 5.0 ,any help or tips would be very much appreciated thank you.

[cb4ever104]

I've had this same problem before with my Zetagi amps . Strange as it sounds , changing the patch leads cured it . Don't ask me why , but it did .

Sammy

[andymuza]

SSB/AM switch may not be functioning correctly.

Does it do it on all power levels from lowest to highest?

Check the drive from the radio in SSB is good enough to drive the linear by checking output power and mic gain.

[wa10]

Can you be more specific, there's different kinds of relay chatter, some of them don't mean the amp is faulty,

you get the relay dropping out between words or syllables when the ssb delay is not working, easy checked by keying on FM and listening for the difference in how fast the relay drops out when you unkey with the amp in FM vs ssb setting

relay will also drop out on ssb peaks if the power supply is not man enough for the job and its folding voltage back, you need a good 40a+ on ssb peaks,

the relay can sit chattering as soon as you key the mic in ssb if you have common mode issues,

changing patch lead length changes the electrical length of your common mode path down the coax shield & through your equipment to ground,
doing that can cure rfi issues if the change in length reduces cmc below what causes you rfi issues in the shack, no radial endfeds like imax are well known for cmc issues if you have an unlucky coax length,

other amps not usually RM500 are sensitive to the patch lead length/load on their input port,

having the radio & antenna coax reversed can also cause instant relay chatter on AM/FM.

[prettypolly]

I went over the schematic diagram and found something that should not be there I clipped it and the chattering has stopped the power is 300 ssb and 180 am FM

[prettypolly]

The psu is 12.20 volts at 65 amps ..

[wa10]

65a is more than enough, 180w is not pushing the transistors far beyond their rating either.

[cb4ever104]

changing patch lead length changes the electrical length of your common mode path down the coax shield & through your equipment to ground, doing that can cure rfi issues if the change in length reduces cmc below what causes you rfi issues in the shack, no radial endfeds like imax are well known for cmc issues if you have an unlucky coax length,

Thanks for the clarification