TenTec Argonaut V Repair Part 2

Part 1 see here:
• TenTec Argonaut V Repa...
The Argonaut now works after having replaced the bad filter. There is not much more to say about it and I goofed up the footage of the actual repair :-(.
This is the link of the Greek page mentioned in the video -- thanks again Bob Ograv for pointing this out:
sv8ym.blogspot....
Part number on mouser.com for the murata CFWLA450KEFA-B0 filter used as replacement:
81-CFWLA450KEFA-B0

[@aureliobelloiz8egm627]

Matt - fortunatly I found your video. My Argonaut V is showing the same problem. Just i have bought the filter Murata on ebay to repair the rig as soon as possible thanks

[@eduardopower5254]

how it goes??

[@aureliobelloiz8egm627]

@@eduardopower5254 very easy to repair

[@h2otek312]

Glad to see the follow up. Those were poor conditions for SSB but that 516 excels at digital modes which are perfect for those conditions! Very happy to see the successful repair. 73 de AF6IT

[@PapasDino]

Matt - many thanks for the update! I would be interested in your proposed experiment to see if the filter failure mode could determined. Funny about the band conditions, nothing ever seems to work when you're trying to demonstrate it! Look forward to your future video episodes. 73 - Dino KL0S

[@loughkb]

Corrosion can certainly be accelerated by electrical current. But it has to begin somehow. I wonder if the supplier of those filters is in a humid climate. Maybe a small amount of moisture is in the case from the factory and they will all die eventually. If they're corroding, then it's definitely a manufacturing process problem. Thanks for the look inside the failed filter. I sometimes do autopsies on failed components myself.

[@MrCircuitMatt]

Thanks for your comment, I fully agree. I've also been wondering about the following: Even if you implement the AC coupling caps, you will still end up with a small amount of DC. A super small amount of leakage current but it's there... I guess that reducing the current will increase the time until the filter goes bad, but it would still happen. Then again we're talking many orders of magnitude so the effect is probably just negligible. Interestingly my dad hat this radio on the shelf for many years, it wasn't used much. I don't know who supplied the original filters, but the replacement filters are murata brand.

[@AF2Zradio]

Ten filters to experiment with! Here in the US I can't find any of these "EFA" filters to fix my ArgonautV. Mouser has some "HFA" series- same center freq & similar impedance, but the bandwidth and selectivity are different. I only use the rig for CW so maybe will give it a try. I guess that will by my filter experiment, haha...

[@MrCircuitMatt]

Unfortunately the filters I got for experimenting are not the exact same type, otherwise I would have sent a few of them over to you of course. Any chance of getting them from those guys? octopart.com/search?q=CFWLA450KEFA-B0+

[@chuckbaldwin7858]

Matt - So glad I found your video. My Argonaut V showing is the same problem. Just wondering where you purchased the filters you have. Thanks! Chuck KD8PFE

[@MrCircuitMatt]

I'm glad I could help. The filter is model CFWLA450KEFA-B0 from Murata. I ordered from mouser but the part was discontinued in the meantime and mouser doesn't stock it anymore. Looks like you can still get it from places like rf-microwave.com or ebay, though. When sourcing a replacement filter, it's important to get the center frequency, the bandwidth and the input impedance right. (Compare with datasheet of the original part.)

[@MartinPHE]

Epoxy seal it would be the best guess just do it in a low humidity spot until cured. Here's a little information of interest while not the same component still same theory tetech.com/wp-content/uploads/2013/10/ICT97MJN.pdf . Doesn't look like it's hermetically sealed from the datasheet. They are not going to be replaced as they are end of life, maybe stock up if you don't find a solution.

[@MrCircuitMatt]

Heh that would be a fun test condition to add if I actually replicate the experiment, thanks for pointing that out. Although a number of people suspect that the contamination is there initially because it's introduced in the manufacturing process. Sealing would surely help for conditions like those described in the paper, but if it's contaminated before sealing then it would still go bad eventually (I think).