Re: 7000 intermittent?


Kurt Sweeny
 

Wow ! Interesting problem, can’t wait to hear the diagnosis.

 

Some thoughts:

  1. The antenna system has the possibility of becoming a  dynamic load (low probability), not so for a dummy load in working order.
  2. Doesn’t 6M share some / a lot of transmission circuitry with HF (same so-239) ?
  3. If the answer to b is yes and 1-30Mhz is OK, could this be a component failure that only occurs above a certain frequency.
  4. The problem is intermittent. What components can fail and briefly recover?

 

Kurt

KD6LZV

 

From: ic7000@groups.io <ic7000@groups.io> On Behalf Of david vanhorn
Sent: Tuesday, June 1, 2021 9:40 AM
To: ic7000@groups.io
Subject: Re: [ic7000] 7000 intermittent?

 

"Fire and glass"?

 

 

 

On Tue, Jun 1, 2021, 9:53 AM wabate via groups.io <wabate=verizon.net@groups.io> wrote:

Hi All,

After using my 7000  for years Murphy has shown up but in a way that defies my logic.  I typically do not use it on 6M.  I was testing on 6M and i twas receiving well.  Went to transmit (RTTY mode) full carrier but was only getting 20 watts out and the SWR was max.  Checked the antenna with another rig and the antenna was fine.  Put a dummy load on the 700 and got the same low output and high SWR.  Puzzled, I tried another dummy and got the same result.  Power was measured with my Bird meter. 

This is the goofy part.  Went back to the antenna and maybe one out of three key downs the output went to 80 W and a decent SWR,  Could not duplicate that anomaly with the dummy load.  Thought maybe the antenna relay was intermittent so I tried HF and got full output and low SWR into the dummy load.  Did not try UHF. 


My guess is the SWR sensing circuit is faulty.    Is the 6M SWR sensing circuitry different from HF?  I'm a fire and glass guy so limited on what I can do with SMD.


Comment?


73 and TIA,


Bill, K3PGB

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