I have a MD-100 that is trying to interface with a YAESU FT-840.
The filters in the MD-100 requires 5.0 VDC that the FT-840 can't provide.
So, I tried an external 5 VDC to the MD-100 but have failed to identify which trace must be cut so that the filters will operate.
Has anyone done this mod before?
YASEU has an application note for this, but they will not release it to the public.
Any help or direct would be most appreciated. Thanks
John, N6TRC email@example.com
Do you have the spec sheet for the mic? This source says supply +5v on Pin 2 of the circular connector.
I wouldn't go cutting any traces.
1. Supply voltage thru pin2 of the circular connector and use the modular connector for connection to radio
2. Add additional wiring to internal circuit board for battery/power supply
3. Wire up circular connector for connection to radio, but with breakout wiring to power source
4. Modify the radio to provide power thru existing pins.
"RF gotta go somewhere!"