Pagina 12
KB2LJJ Radio Mods Database and Manuals
03/05/2008 08.24.31
http://www.kb2ljj.com/data/yaesu/ft-817.htm
The green trace is stock FT817 the blue trace is with 1000uF.
Improvement of the optional microphone MH-36 E8J with DTMF
Author: Andreas Duessler
Hi ladies and gents,
The original microphone works good, but I tested also the DTMF-microphone, which is available now. It
sounds really bad, and that wondered me, because a small electret-microphone is inside. But after
opening the mic, the reason was easealy located. The necessary DC-voltage, comes to the microphone
via a small resistor. The value of this resistor is by far too low - replace it to a value near 10 Kohms.
Now the microphone is better than the original one and has all these options like DTMF and it´s
backlighted !
The picture should help to locate the small resistor. The new one is a traditional one ( I had no SMD-
resistor )
It looks bad, but it works fine....by the way the new microphone is very sensitive now...go down to
values of 20 (original is 50 !) in the setup of the FT-817 specially in SSB.
