Kenwood TR-751E impulse noise during scan

[HG5AZR]

Hi!

If my Kenwood TR-751 is in scanning mode I hear impulse noise(about in every 0.1 second) from speaker if I near the speaker(5cm) or use a headphone.
Can you check and hear it with at other TR-751?
What cause this problem?
Other people doesnt have this problem with TR-751.
I realised that if I rotate the main dial I hear also this sound .Why?


Thanks
Zoli/HG5AZR

[CT2HMX]

Hello friend.What kind of impulse you heard in the speaker??You can measurement the impulse in a scope??I not have this radio but once a time in a CB who have the scaning function i had same as failure,during scan a sound like a beep about 0.2sec appears when channel moves.The beep frequency was about 400hz view in a scope.I study the diagram and service manual,once a time
i saw in the internet one failure exactly the same with my CB radio.The solution was change a few capacitors in the sound amp. and in the PLL and VCO, this capacitors is used to filter any harmonics generated by high frequency circuits who appears in low frequency circuit.
I know the radio is not the same but it is maybe one a solution for this kind of failure.

73 from Hugo Barata CT2HMX