The ceramic filter strikes again !!

I had experienced this few years back with my handheld (https://icemanjeep.blogspot.com/2015/04/the-deaf-yaesu-vx-series.html - http://www.pakhams.com/index.php?option=com_kunena&view=topic&catid=4&id=421&Itemid=147) and this time it was an Icom IC2200H which is my jeep's rig.

 As in the video below, the symptoms were identical but the solution to the problem is different from the video. 

The myth popular on the internet is that the small DC voltage being applied to the filters is causing them to fail.  People are replacing the filters and installing DC blocking capacitors and of course this works.

However, the filter catalogues and data sheets all say that a small DC voltage will not harm the filter in any way. 

I also think it’s unlikely that Yaesu, ICOM and Kenwood engineers collectively got it wrong. If you look at the ceramic filters in a faulty radio, they will be covered in a white salt-like deposit.  If you break open the filter cases, you will find a turquoise deposit inside.  The plastic that the filter housings are made from is hygroscopic; i.e. it absorbs moisture…which it then releases when it warms up.  It then absorbs more when it cools down and the cycle continues until the turquoise copper compound shorts out the filter’s internal structure.

So…it’s down to hygroscopic TOKO plastic…not DC voltage; the electrons are innocent! It doesn’t matter if the radio has been kept in a warm dry house either; the filters will still eventually fail.

PY6TG in video uses a

in place of a  450KHz BPF below.

So lets start with the IC2200H, when opened from the bottom, the filters are as below

I ended up with the following as I was tired of desolder and solder near smd devices

made sure that the filters when plugged in are tight

Just a sample below, the soldering side and the extreme close proximity of smd devices that make it hard to do it again and again

Now for the fun part, almost 09years back, one of my first base station a kenwood TM271A, the story (http://www.pakhams.com/index.php?option=com_kunena&view=topic&catid=7&id=371&Itemid=147) low receive sensitivity. Back in the day didnt check the WBPF or NBPF and eventually packed it up for storage, didnt cross my mind when the-deaf-yaesu-vx-series event happened few years back but this time with the IC2200H, it just came to mind to test the TM271A W/N BPF and the N-BPF worked but deaf in W-BPF. Opened it up, and the below solution as with IC2200H

Now the signal has returned !!! 😀

Resources and Credits

SV8YM: The Mysterious Case of the Withering Filters
http://sv8ym.blogspot.com/2010/07/mysterious-case-of-withering-filters.html

Yaesu FT-897 Ceramic Filter Problem – M5POO…the website
http://www.m5poo.co.uk/yaesu-ft897-ceramic-filter-problem/ 

Repair: YAESU FT-857D IF filters replacement - YouTube
https://www.youtube.com/watch?v=sEENjwyzkw8

SV8YM: More on the withering filters case: The TS-2000 disappearing noise conundrum
http://sv8ym.blogspot.com/2010/10/more-on-withering-filters-case-ts-2000.html

SV8YM: The Withering Filters: A microscopic view
http://sv8ym.blogspot.com/2011/01/withering-filters-microscopic-view.html

Yaesu FT-897 Ceramic Filter Problem – M5POO…the website
http://www.m5poo.co.uk/yaesu-ft897-ceramic-filter-problem/

Kenwood TM-V71 Filter Issue – M0LMK
https://www.m0lmk.co.uk/2017/12/19/kenwood-tm-v71-filter-issue/

A cure for Kenwood and Yaesu Ceramic filter pandemic. – Nostalgia Microphones (Ham & CB)
https://lx2smlx2ooo.wordpress.com/2015/12/06/kenwood-and-yaesu-ceramic-filter-pandemic/

ft1900 IF filter replacement
https://qsl.net/k2mpw/FT1900/default.htm

September | 2014 | Radio – LF/MF to Microwaves
https://g3zjoradio.wordpress.com/2014/09/