[Yaesu] Fwd: Deaf FT-901DM

[Steve Sutfin]

Steve,
  I might have missed the latest but did you get this resolved? If  
so, how?
73,
Steve
k7dna

On Apr 26, 2015, at 4:10 PM, n3sb at qis.net wrote:

> Hi Wayne;
>
> Thanks for the suggestion. I will give that relay a close look.
>
> From the RF connector on the back of the radio, I can measure a  
> very low DC resistance to ground, which would probably be the  
> primary side of T1. When I hit the attenuator button, the DC  
> resistance goes up corresponding to the resistors in the pi  
> attenuator network.
>
> I hope to get some time soon to walk a signal generator through the  
> RF and IF stages in the radio, to measure their gain - hoping to  
> find the area where the problem is lurking.
>
> I still find it very unusual the way the calibrator level drops  
> when a load is connected to the radio. So I'm really suspecting  
> something in the front end.
>
> 73; Steve, N3SB
>
> Quoting wayne johnson <k9wkjham at gmail.com>:
>
>> have look at the change over relay
>> my ZD had a similar issue before tha magic smoke came out of the  
>> mains
>> transformer [?]
>>
>> On Sun, Apr 26, 2015 at 1:54 PM, <n3sb at qis.net> wrote:
>>
>>> I should add that I've tested the Attenuator switch and it is  
>>> behaving OK.
>>>
>>> 73; Steve, N3SB
>>>
>>> ----- Forwarded message from n3sb at qis.net -----
>>>     Date: Sun, 26 Apr 2015 14:45:35 -0400
>>>     From: n3sb at qis.net
>>>  Subject: [Yaesu] Deaf FT-901DM
>>>       To: yaesu at mailman.qth.net
>>>
>>>
>>> Hi Folks;
>>>
>>> I picked up an FT-901DM recently that's got a deaf receiver. I've  
>>> checked
>>> the antenna fuse and it's good. Also checked the first RF amp  
>>> transistor by
>>> plugging it into a Kenwood radio, where it worked fine. I've re- 
>>> seated the
>>> plug in boards and done a little other basic poking around.  
>>> Getting 50
>>> Watts out from the transmitter with an old pair of 6146's.
>>>
>>> The calibrator level is about S-7 on 20m, and the preselector  
>>> does peak
>>> the calibrator in a normal way. However, when I connect a dummy  
>>> load to the
>>> antenna connector, the calibrator level drops down to an S-1. Is  
>>> this
>>> normal behavior??
>>>
>>> 73; Steve, N3SB
>>>
>>>
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>
>
>
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