[Yaesu] New Rig: an FT-840. Your experiences ??

[Dr. Gerald N. Johnson]

The standard 6 pin ham gear power connector uses .084 pins, not the most 
easily found .063 or .093 pins. So sticking in plain .093 pins probably 
has expanded the pins in the radio connector. They should take squeezing 
in gently in several angles with small needle nose pliers or forceps.

The pilot lamp has three requirements, size, voltage, and current. Check 
the circuit diagram to see how its powered, then look for the available 
lamps that run on that voltage and will fit the space available. There 
may also be selections for various lifetimes where the longer lived 
lamps will have less light output.

In general, lowering lamp voltage with a series resistor has a great 
benefit in lamp life. One lamp reference book I have says lowering 
voltage 5% cuts light output 10% but doubles lamp life. In addition a 
series resistor limits the peak current at turn on for better lamp life. 
Tungsten changes resistance between 15 and 16 times between room 
temperature and the white hot operating temperature of the lamp 
filament, so the current surge if not limited externally is 15 to 16 
times the rated operating current.

There can also be LED replacements with a lot longer life.

73, Jerry, K0CQ

On 7/9/2014 8:16 AM, Doug Hensley wrote:
> Greetings,
> I am new to the Yaesu list.
> I've just acquired a Yaesu FT-840 transceiver; no power supply, no mic, etc.  To test the receiver I put molex pins on the back receptacle and powered it up on a dipole.  Thereceiver works great.  I have not read enough of the manual to start testing the trans-hitter but hope to soon as I fix the new power cord I bought for it.
> Some questions:
> The generic power cord which is labeled to fit a dozen Yaesu models has a bit larger molexpins in it than I am comfortable with.  When I insert the 6 pin plug, there is no feel ofcontact until the plug is almost all the way in.  My thought is to buy a pin extractor andlightly crimp the female plug pins before attempting to pass a lot of current throughit.  Am I doing the obvious or is this the way all Yaesu receptacles feel ?
> Secondly, the pilot lamp is out.  Looking through the Technical Supplement I found online,there is no identification on it that makes sense.  So I am guessing 12V and thinking LED replacement?  Has anyone found a best fix on this?
> I would enjoy hearing some chatter on the FT-840 if you have used one.  Thanks.
> Doug W5JV/NNN0BXX
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