[VHFcontesting] Yaesu FT100D problem on 6m

[Dave Olean]

John,
    No one seems to have direct knowlege of what is actually wrong. I 
suspect that you need to find the SWR sensing circuit and follow the rf path 
to the output fitting. It must be a significant length on 50 MHz at least to 
ruin the 50 ohm path. The way to find it is to inject a  signal with a SWR 
bridge and sig gen right at the SWR circuit board and look towards the 
output connector. You can see what the SWR is with a 50 ohm load in the 
connector. Poke and prod to find what is making the SWR bad. An antenna 
analyzer would work ala MFJ or Rig Expert. I have a homemade bridge that is 
good to about 500 MHz along with a signal generator (with 1000 Hz tone) and 
an HP 415E SWR indicator. It would work swell for this too. Otherwise, you 
have to rely on your own lyin' eyes. I am thinking that a poor or missing 
ground might allow a part of the circuit to lift and act as a tuning stub 
and ruin the nice 50 ohm path. I wonder if there is any filtering after the 
SWR circuit. It could be flakey. Without a schematic or seeing it, it would 
be hard to guess.

Dave K1WHS
----- Original Message ----- 
From: "John Geiger" <af5cc at fidmail.com>
To: <gmitch at iowatelecom.net>
Cc: "vhf contesting" <VHFcontesting at contesting.com>
Sent: Thursday, February 12, 2015 4:36 PM
Subject: Re: [VHFcontesting] Yaesu FT100D problem on 6m


> What was the fix for this?  It is a late model (2L serial number range)
> that should have the grounding mod done at the factory.  It doesn't seem 
> to
> have problems with any other bands, like some of them did.  This is one
> temperamental model, that is for sure.
>
> 73 John AF5CC
>
> On Thu, Feb 12, 2015 at 10:12 AM, <gmitch at iowatelecom.net> wrote:
>
>> I had 2 of the "D" models that also did this as well as 3 of the pre "D"
>> models. I do
>> believe the "D" models I had (still have one) were the early models as
>> well.
>> I also had a FT-897 that did this as well.
>>
>> 73
>> Gene
>> N0DQS
>>
>> -----Original Message----- From: Tad Danley
>> Sent: Thursday, February 12, 2015 6:19 AM
>> To: vhfcontesting at contesting.com
>> Subject: Re: [VHFcontesting] Yaesu FT100D problem on 6m
>>
>> I think some early D models had this problem as well.  I purchased my
>> FT-100D in 2000 and had the high SWR problem on 6 and 10.  A warranty
>> trip to Yaesu fixed it with the additional grounding.
>>
>> 73,
>>
>> Tad Danley, K3TD
>>
>>
>> On 2/12/2015 6:08 AM, Mike (KA5CVH) Urich wrote:
>>
>>> On Wed, Feb 11, 2015 at 8:54 PM, John Geiger <af5cc at fidmail.com> wrote:
>>>
>>>  I have not seen this problem in a FT100D before.
>>>>
>>> Mike asks
>>>
>>> Are you sure its a "D"?  This was a problem on the "pre-D" models, not
>>> only on 6 but 10 & 12 as well.  My "non-D" had to go back to Yaesu so
>>> they could do the additional grounding that was necessary.  They
>>> repaired it and shipped it back to me at no cost.  They also flashed
>>> the firmware to the "D" firmware at the same time.
>>>
>>> No problems since.
>>>
>>>
>>>
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