41-605 Squeal/Motorboat - Printable Version

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+--- Thread: 41-605 Squeal/Motorboat (/showthread.php?tid=22936)

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41-605 Squeal/Motorboat - glwells - 10-28-2021

I'm working on a 41-605, replaced the obligatory caps as well as some dominos, out of spec resistors, checked tubes, general socket and pot cleanups, etc. The AM side plays fine up to about 1400 where the oscillator starts the infamous squeal and motorboating right up thru the top of the dial. All good below 1400. The SW side works fine with no issues. I have it isolated to most likely issues with the oscillator circuit. A NOS 14AF7/XXD didn't help. Resistance specs of the oscillator coil are good. I've maneuvered lead and component placement as much as I dare in the oscillator area around the XXD. Oscillator padder 17A does impact the intensity but doesn't eliminate it. Can anyone offer any suggestions or hints as to what I may have missed?

Much appreciated.

Gary
WB9AYD

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RE: 41-605 Squeal/Motorboat - vinzer - 10-29-2021

Are all tube shields on?

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RE: 41-605 Squeal/Motorboat - glwells - 10-29-2021

These are Loctals and I cleaned all of the tubes and sockets.

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