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Yaesu FT- 23R mods
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FT23R.3
3.The only indication of low power operation is in the memory mode.
A "C" will appear in the upper left corner of the display (where
the primary "P" used to be). The bargraph will always read 100%.
4.The band scan is now even more useless. The uP will painfully
count from 50 to 300 MHz.
I have been able to modify my FT-211RH to scan at about 10 chan/sec
by speeding up the uP clock. This also speeds up every other uP
function by x5, so you have to be fast on the "F" key. No squelch
sensitivity or synthesizer lock-up problems have been encountered
with this modification while scanning.
Basically, I replaced the 800 KHz ceramic resonater (pn CSB800K)
with a Radio Shack 3.58 MHz color burst crystal. The resonater is
located on a small (2.5 sq cm) sub-board that is stuck with double
sided tape to the radio's processer board. This sub-board is actually
an outboard clock for the uP. The schematic I got with the radio
showed the uP's internal osc. being used - so I don't know if my
version differs from newer radios. This mod works fine untill you
turn the radio off and then back on again. A startup glitch then wipes
out all of the memories. To delay the oscillator start up, I added a
220uF 10V electrolytic cap between the red wire on the sub-board
and ground. Positive goes to the red wire. A convenient ground is the
bare wire located diagonally across from the red wire (on the sub-bd).
So far I have been unsuccessful with this mod on the FT-23R H-T.
Since it uses the uP's on board osc, there seems to be no way to
delay it's startup. Every time you turn on the power the uP resets.
If anyone can solve this problem I would be very interested in
hearing from you!
These are not intended to be step by step instructions. Also, you
will want to have a service manual before you begin. If you're not
familiar around surface mount components you may want to "learn"
on something with cheaper consequences. Finally, don't adjust the
VCO's unless you are familiar with how a synthesized radio
works. Use your own judgement!
--
/ Ken Gianino
WB0QNA ** \
Note: I haven't tried this, proceed at your own risk. WA2ISE
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