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FT-857D Static Noise Fix

There was a common problem with Yeasu's FT-857D ham radios, in which - for no apparent reason, static would chop through in almost every mode and any band. I believe this wasn't apparent in the AM band and possible less of an issue in the HF bands. But otherwise it seemed to happen everywhere

The issue was often an S9+ burst of static, which would not be steady, but would happen randomly, usually getting progressively worse as the radio warms up. It didn't matter if an antenna was connected or not, or what type of power supply was used.

The fix is actually fairly simple if you also have this problem. The reason for it is likely a 455khz AM filter which has gone bad. Below is a photo of a tarnished plate found inside my 455khz AM filter after removing it.

Filter

Usually the filter which is the problem is the 455H filter, located right next to the larger silver filter. I believe it is CF1, or perhaps CF3. I can't tell from this photo and I didn't momorize the silk screen printing when I was working on it.

455khz Location

Desoldering this filter requires moderate to high soldering skills. The pins are small, and very close to tiny surface mount components which are no bigger then a grain of sand. Not only hat, but 3 of the pins are ground references, and thus they are soldered to a huge ground trace which wicks heat away, making it very hard to desolder.

Desolder

The replacement can be cheaply had from Yeasu. Simply call 714-827-7600, ask for parts.
The "H" is part number H3900588. I also replaced the other 2 black filters while I was there. They aren't very expensive. My price was $0.71. So I ordered a "E" (H3900587) and a "G" (H3900589) as well. Also, they changed the part numbers and are now going with a different manufacture. So I do imagine these are of a better quality.

All in all plus shipping it ended up being $3.49

After all is said and done, the unit is working as if it is brand new again. I should of done this sooner!. Hope this helps! And if any of you want me to do this work for you... Contact me.

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28 views since Feb 2 2024

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