Splendor servos squeal

The Eflyte Splendor I have just purchased is now connected and the servo's (all of them) make a squealing noise, like you get when they are stalled or overloaded.

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2. I have removed the control arms and they still do not find a "happy quiet position" readily, although sometimes they are quiet (never all at the same time though)

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4. So I substituted the superb Taranis receiver (just in case), no change..

5. I used a different ESC, no change

6. I re routed the wiring no, change.

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8. So my conclusion is that Eflyte 7145 (26gm) servos squeal a lot sometimes?

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10. They seem to work OK.

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12. I am aware the aircraft has been idle for quite some time, so I am exercising the servos, I maybe delusional but they seem to find more happy positions?

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14. Technically I wonder if the PCM frequency adrift? and the servos are hunting, is there any such as (we say in Wales) thing "occurring"

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16. Any ideas welcome.

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18. I could of course scrap them but a lot of work and money for a squeal!!

19. Roger