WARNING! Any modifications made to your equipment are 
performed at your own risk.  Be aware that these mods 
will probably void your warranty. The authors and 
Webmaster assume no responsibility for damage caused to 
your radio.

1. A modification to open up the radio (updated)
2. How to activate the hidden Alignment Menu
3. Quieting a noisy fan
4. Creating more reasonable audio output levels


1. A modification to open up the radio (updated)

Extending the transmit range
The modification posted earlier in this location was not 
working on most units.  Here is a mod which appears to 
be correct:
Remove bottom cover..near battery there are 6 solder 
pads numbered 1 thru 6....pad 1 is already shorted with 
a chip resistor.....short pads 2 and 3 with 
solder...check pad 6 and if it has a chip resistor on it 
...remove it...this one has to be removed to go out of 
band on hf and 6m.....replace cover and turn on radio 
while holding in the lock and fast buttons....this 
resets micro and you will also lose all your memories 
that you have entered...you will have to reprogram 
these....TX coverage will be 1.8-76mhz with
no gaps...DO NOT TX BETWEEN 30-36MHZ -- not only is it 
illegal, but you may damage the HF PA.
Thanks to Tom KF4TRZ, Brent K9WV, and others for sharing 
this information.


2. How to activate the hidden Alignment Menu

George Nelson WB7VWK     Email: 
WB7VWK.GEORGE@worldnet.att.net
I have just received the Technical Supplement (Service 
Manual) for the Yaesu FT-847. This radio has an 
Alignment Menu in addition to a User Menu. To enter this 
Alignment Menu, you turn off the transceiver, press the 
UP, DWN, and FAST keys on the microphone together, while 
turning the transceiver on again.
In the alignment procedure, each alignment parameter is 
selected by rotating the SUB-TUNE dial. The alignment is 
performed by pressing the MCK/W key while injecting a 
signal of the required frequency and level. Pressing the 
MENU key after a setting is made stores the entry. To 
exit the alignment routine, press POWER.
This radio seems to be very high tech in all. I have not 
entered the Alignment Menu, and do not suggest that 
anyone do so, without the proper test gear and 
electronic knowledge.


3. Quieting a noisy fan

Dave Sublette K4TO - Help with a noisy fan
A common complaint about the FT-847 is that the fan 
noise is irritating (and it is).  I have been able to 
quiet the whine using the following method:

Cut a 3" x 3" piece of soft packing foam that is about 
2" thick. Be sure to use the "open cell" type of foam.  
You can tell that it is open cell type construction by 
holding it up to your mouth and blowing air through it. 
Wedge the piece of foam between the four coax connectors 
so that it covers the intake area for the fan.  The 
whine will then disappear.  The foam has little effect 
on the cooling of the radio.  I think it works
because the foam causes turbulence in the air flow, 
disrupting the formation of the sound of the whine, 
which is probably generated by the tips of the fan 
blades.  It may even slow the fan a bit, which stops 
thenoise.  However it works, it works.  I can't even see 
it when it is in place. It should also have an added 
bonus in that it will filter dust from the air before it 
enters the radio.

Hope this works for you.


4. Creating more reasonable audio output levels

Bob Nagy, AB5N - Throttling back the audio output level
Although Yaesu did a fantastic job of gain distribution 
in the FT-847's receiver, they bombed when it came to 
the last stage...the audio output. The volume control's 
lowest setting results in room filling audio. The TDA200 
audio amp chip is not actually being over-driven, it 
just is getting too much audio signal at the lowest 
input level from the previous stages. A great 
improvement can be gotten with the following mod.

Take off the covers and turn the rig over on its 
top....exposing the bottom. Near the rear, opposite side 
from the power input connector, you will easily be able 
to locate the audio amp IC. It has 6 legs and is next to 
the purple 470mf capacitor which it's output goes 
through. The input to that amp comes in on it's #1 pin - 
which is the long leg -at the end nearest the rear of 
the rig. You can see the small 1uf cap feeding it -quite 
close to it. The mod is to add a 47K resistor in line 
with that leg. The easiest way is to snip it in the 
middle of the leg..seperate the snipped conductor and 
add the 47K in series with the two leads. Prepair the 
1/4 watt 47K resistor with just enough lead length to 
contact the seperated amp leg. "Tin" resistor and leg 
contact points and tac solder the resistor in. (be sure 
that the leg is really seperated). Remember-You can 
always remove the resistor and bridge the leg together 
again at a later date.

The 47K gives just enough level reduction that you will 
now set your volume control at 11am instead of 10am, and 
the innitial lowest level point will be about half what 
it was. You may find that 68K or 100K may still provide 
acceptable volume levels.  There is still enough audio 
to "blast out" the internal speaker...or drive any 
external unit.  I even think that the audio sounds 
smoother and cleaner at this input level. 
Good Luck and 73’s!

Bob Nagy  /  Chief Eng.  KVRX FM  /  KVR-TV9
Amateur Radio - AB5N    442.15/R    1292.3/R 
email:  www.botany.utexas.edu/facstaff/stfpages/bnagy