RCI 2990 talk back problem, can't get it turned off.

[euhara]

Radio Make and Model: RCI 2990
PCB Number: EPT295013z
PLL Number: ?????
Test gear available: DVM Freq. counter, watt meter, mod meter Solder station

Symptoms: Can't get rid of talk back

What is working: Everything

What has been tried: Checked and tested D78,D100,D47,IC16,IC19,Q41,Q42,Q45,Q52,Q53,Q55, C138 all voltages are normal.

Did it suddenly happen ?: Yes

Anything else that may be of help?: It all started with making a chirp then a loud continuous high pitched tone through the speaker whenever mode switch was changed to CW mode and keyed up, after that any mode would cause the tone to sound. It is not the roger beep tone. The only way to stop that was to turn mode switch to PA mode or switch the radio off.
Turned the radio off for the night, next day the tone was gone in any mode, never did that again but now it has permanent talk back, can't get the talk back to go away.
Other than this the radio works perfectly.

Any Ideas gladly appreciated.

Jim

[euhara]

Thanks anyway, I got it fixed

Jim

[captian_radio]

Please share what you found that was the problem with us.
Bob