Yaesu FT-847 Modification Manual page 12

Modification Yaesu FT-847 for 70MHz
Part II – practical solution v. 1.0 (Oct 2013)
Greg SP3RNZ sp3rnz@wp.pl
PA mod idea by Marc PA1O
TX/RX mod idea by Hellar ES1II/8
This article describing how to do modification of your RIG in practice.
Theoretical aspect were described in previous part of the article about modifying
Yaesu FT847 RX/TX filters to get all we can have from this nice radio. Because You
probably read part first before ( if not – I insist You should!) I will focus on practical
aspect of the mod.
The job we need to do is:
- unlocking the radio, if it's still locked to gain access to 4m,
- remove capacitor in PA module to increase TX efficiency
- replacing existing RX Bandpass filter to modified one with LNA,
- replace existing TX filter chain to sharper one to get clean signal.
Let's get it started ;-)
1. Unlocking your FT847 to get 4m ( for those who already have unlocked
one, please move to chapter 2).
Assuming we have fresh one locked 847 on the workbench we should start with make
it alive on 4m. Job is easy, and should not take long time even if You haven't much
electronic experiences.
First unscrew top and bottom cover, and turn the radio upside down. If You have Your
radio facing with the main tunning knob facing You, look on the left upper corner.
There is Lithium battery, and on the left You will see six solder points marked 1-6 .
They could be just shortened by solder, or small SMD 0Ohm resistors. On the picture
You can see factory state unmodified 847.
Regarding our needs and mood we can do the unlocking in two basic but different
ways.