FT-817 finals?

[WE...@aol.com]

It seem that I likely now have an FT-817 with a bad RF output module.  I suspect it happened when I was last portable and discovered I had the antenna hooked to the rear connector, but it was programmed for the front hookup-OOPS!  An expensive mistake, to be sure....if that is what caused the problem.

I believe there was a thread about this a while ago, and of course I was not interested enough to save it; nor to even remember the outcome of the discussion.

Is the final module available or not?

For some reason I cannot get into the PNWVHFS googlegroup search routine, to find the related postings.

Rod Johnson

 

[Eric Smith]

Actually that rig uses a single, wideband FET transistor as its final... I'd have to dig through my manual pile and locate the schematic for the exact part number... but its "bigger brothers" use the same device, paired, for a pre-driver stage on the main board.  I checked the price a couple years ago and its widely available from various parts houses, the price in the $5.00 range.  Trick is there are no "leads"... but "pads" underneath the device so desoldering would be tricky... I need a pair to get one of my FT 897's "on both feet" if you will.  Fortunately the '817 device is on its own "daughter board" so that whole assembly could be removed from the "chassis" board and likely make device replacement a whole lot easier than removing the paired devices from the "main" board of the bigger radios.  It might be a good idea to use this as an opportunity to put together some sort of "group purchase" so as to hit some "price break" point, and may result in a "collective" reduction in shipping charges...

Eric
KB7DQH

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[Mike Lewis K7MDL]

I think the most recent discussion was the about the FT100 finals.  A couple years ago I got a new FT-817 finals board (about 2" long) from Yaesu for around $50 I think.  Worth a call to them and see if you can still order from stock.   They are still sellingthe FT817, I would imagine they have a replacement board still.   Until the board arrived, it was still good for a microwave IF rig.
 
The final amp is connected to teh power supply input and charging circuits without much else in the way.  It is reported, and maybe happened to me, susceptible to damage by external power cord shorts (when a battery is installed) and other power supply issues.  As a result I built a small box on teh back that has a reverse polarity diode, a 8V regulator (switchable) and a powerpole connector to beef up that area.  It was from an article at http://www.wulfden.org/TheShoppe/ft817/index.shtml.   Much, much more info and a how-to reapir is located here http://www.ka7oei.com/ft817_rfpa.html
 
 


Mike Lewis
K7MDL
Grid Locator CN87xt
Member of Pacific Northwest VHF Society #C96 (www.pnwvhfs.org)
Visit the K7MDL Amateur Radio Pages web site at http://www.K7MDL.NET
Elecraft K2 #2633
 



 

---

Date: Wed, 11 May 2011 03:29:35 -0700
From: kb7...@donobi.net
To: PNW...@googlegroups.com
Subject: Re: [PNWVHFS] FT-817 finals?

[n6...@aol.com]

I have been using the 'power conditioner' as described below for the whole time I've owned an 817. Works out well.

 

The recent Yaesu multi mode rig thread WAS the FT100. I solved my loss of VUH/UHF final by purchasing a used FT-100 R/T from a friend who had had his face plate/control head stolen along with the pick-up truck the rig was installed in! 

 

bt73Pete, N6ZE

[Jim Lowman]

Rod, I haven't called Yaesu Parts Department on this, but was told
recently that a new final module with a heftier set of finals was available.
Apparently there was an issue with the older FT-817 (non-ND) models that
if the battery pack was left in for extended periods of time and allowed
to discharge fully, it could take out the finals even if power was off.
I was an early adopter of the 817, buying one at Pacificon about 10
years ago. Then the radio sat for a long time until I retired recently,
so I was afraid that I'd be buying new finals. I bought a new Yaesu
battery pack, fired up the 817, and all was well.

There is a very active FT-817 group on Yahoogroups, BTW.

72/73 de Jim - AD6CW