[Yaesu] FT890 strange behavior

[Michael Tortorella]

Thanks to everyone who offered help and suggestions. Here's what I have concluded so far. the problem is definitely RF getting into the PS. It comes and goes depending on (1)where the PS is located relative to the radio and (2)which band I am operating on. The antenna system is a short center-fed vertical without radials (for those who remember, it's a Mini-Products C-4, possibly the last one on the air anywhere!) fed with 50-ohm coax. Unfortunately, I am currently on vacation and my options are somewhat limited so I think for now I will just fool around with PS placement. When I get home I can take more serious steps along the lines suggested (probably ditch the PS first of all, folks on this list are not the only ones who are not fans of Astron). 

Not exactly a pileup-busting setup, but I have worked a couple new ones this week and I am having fun learning the computer control/automatic logging software which I had never used before (still a bunch of boatanchors at home). i do have to say the 890 and built-in antenna tuner has handled the short vertical very well, it even loads up OK on 40 meters which the antenna specs do not support.

Thanks again to everyone, it's always a pleasure to be associated with a fine bunch of folks.

73
Mike

 
 
On 07/11/13, Earl Morse<kz8e at wt.net> wrote:
 
Rather than pile $25 worth of ferrite and filters on it why not take a divide and conquer systematic approach to resolving the problem.

Start with the supply. Can you draw 20-30 Amps out of it with just a plain resistive load? If not, the supply may be defective without even adding the RF part into the equation.

Next add the radio without all the microphones, CAT interfaces, external speakers, etc connected. Transmit into a dummy load at a low power level. Do you notice the issue? Check all bands. If the issue is still non existent increase power and repeat checking all bands. Check CW and Modulated modes. 

If the issue is still not recurring start adding the microphones, head phones, speakers etc back into the equation and recheck functionality to see what it takes to make that power supply fold up. 

The final stage will be adding the antenna and transmitting full power with everything hooked up.

Once you know exactly what it takes to make the supply fold up it is going to be much easier to determine the exact fix. Adding a ferrite bead (what mix??) to attenuate common mode currents when you are uncertain about which frequencies or which cables are even causing the issue (1.8-30 MHz is a big chunk of spectrum)is more of an exercize in how lucky you are rather than how good you are.

Good luck with the process. Let us know how it comes out.

Earl
N8SS

--- w2iy at verizon.net wrote:

From: Michael Tortorella <w2iy at verizon.net>
To: yaesu at contesting.com
Subject: [Yaesu] FT890 strange behavior
Date: Wed, 10 Jul 2013 22:32:10 -0500 (CDT)

Hi all, using an FT890 with Astron SS-30M supply and DX Lab Suite. Receives FB but the instant I hit the key, the xcvr shuts off, the supply voltage goes down to 3 volts. Turn everything off, restart, same deal: receives FB, as soon as I hit the key, the xcvr shuts off and supply goes to 3V. At first I thought it was RF getting into the supply so I separated the two by a couple feet and this _seemed_ to help. But tonight the problem is back fully.

This first happened two days ago. Then last night everything was fine, worked several stations OK. Tonight, problem. Has anyone seen anything like this before? Any advice greatly appreciated.
Thanks and 73
Mike W2IY
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