Yaesu FT-857D

Contents of this page:

1. CPU/Memory Resets
2. Interface Unit
3. Mic Pin outs
4. RS232 Interface
5. Microphone socket with COM port
6. FT857 Squelch failure fix. New info by UN7GDR 10 Feb 2016)
7. Tech Menu Settings

POWER ON MICROPROCESSOR RESETS

Hold down these buttons while turning the power on...

• V/M - Resets all memories and following menu settings to the factory default. Menu 6, 33, 52, 56, 76, 82, 83
• FUNC - Reset all menu settings to default, except for Menu 6,33, 52,56,76,82, 83
• HOME - CPU Master reset for all memories and menu settings.
• FUNC + V/M - Master reset after MARS Mod.

>

My FT-857 D INTERFACE UNIT

Other Information

RS232 Communications Cable needed if above circuit is put in a separate box is a pin for pin type. ie. pin 1 to 1, 2 to 2, 3 to 3, through to 9 to 9 etc.

If you are making the cable, minimum would be: Pin 2-2, 3-3, 4-4, 5-5, 6-6, 7-7, 8-8

Shared Microphone Socket with COM port.

Set menu 20 to CAT/LIN/TUN as required, and set menu 59 to CAT for mic jack use.

Do not use the up/down microphone buttons as they are used for the COM port.

Squelch Failure on VHF/UHF

If you have squelch turned on and no sound is heard until the knob is turned anti-clockwise thereby disabling it, then the following may fix the problem.

Background

TECHNICAL INFO

BY Egor, UN7GDR IS BELOW. (NEW 10/2/2016)

The Fix - by the book

You will need a VHF Signal Generator. (or read below how I did it)

1. Tune the radio to the 144MHz band and turn off the radio.
2. Access the tech menu by holding in A, B and C buttons while turning on  the radio with the squelch turned fully counter-clockwise.
3. Inject an RF signal from the sig gen at -15dBu output, with  +/-3.5kHz  deviation FM Modulation of a 1 kHz tone.
4. Select menu item "13:FM-TH1" and press the A key.
5. Select menu item "14:FM-TH2" and press the A key.
6. Increase the sig gen output level to 0dBu.
7. Select menu item "15:FM-TI1" and press the A key.
8. Select menu item "16:FM-TI2" and press the A key.
9. Hold the function key in long enough to accept the new data.

Here is what I had to do.

I don't have a signal generator so I improvised with a hand held and a dummy load.

I pressed the A key for menu 13 and 14 while on low power and whistling into the mic and pressed the A key for menu 15 and 16 while on high power. This did not work, although values were entered about 80 higher than the original value.

WHAT DID WORK was to put the squelch knob up at about 3/4 clockwise and did the same and now I can actually use the squelch quite successfully on all modes / bands.

Menu Number	Orig Value	New Value
13	90	178
14	95	179
15	4	170
16	4	170

I have since used a signal generator to improve settings, but they remain the same.

Many thanks go to Egor, UN7GDR for the following information...