Patrick Bourgeois:
Hello everyone,

 was at the local hamfest here in west monroe and purchaced a D-104 mic for my HW-101, had to change the plug out on the radio and then the one on the mike, but not working yet. The 101 has just two wires coming off, one for audio and the other is ptt. I installed a 4 prong mike socket, with two pins being the ptt and audio the others I ran wire to a chassis ground since these where ground and the shield. The only question is does anybody know which wires on the 104 are the ptt and audio? I took the mick apart and the black wire appears to go to ptt and the red goes to audio, I know the white is ground, and well the shield is obvious.. but if I hit the ptt I get a direct short accross the ptt to audio plug of the mick?? Also since the D-104 is suppose to be a 50k mick if I stick an ohm meter accross the terminals should I not see some resistance?? Because I get open circuit, no resistance at all?? Any help would be greatly appreciated..


Lon Kinley:
You can't measure impedence with an ohm meter. The element is probably crystal, although some late madels had a ceramic element. You won't measure any resistance across it.

Most of the bases have the schematic glued to the inside of the base cover. If not, the schematics for all the variations can be found at http://www.barovelli.com/radio/astatic/astatic.htm.

Mine shows red and blue as the PTT (floating), white as the audio, black as the ground.


Lon - N3ZKP
Baltimore, Maryland

Gregory J. Beat:
Patrick -

Here are the Astatic D104 wiring diagrams and pre-amp schematics.

The Astatic crystal elements are sensitive to HEAT &  SHOCK (destroys the crystal structure inside)

If you have a dead Astatic crystal element (Hi-Z) in your D-104, a replacement Kobitone crystal element (25LM022) is available from Mouser -- bottom right of page 1312

You have the option of placing a new dynamic Heil element in your D-104 - instead of replacing the bad crystal element.  Bob Heil (Heil Sound) now offers a HC104 Conversion kit specifically for Astatic D-104 owners. Bottom right of this web page.

The HC104 conversion kit includes the Heil HC 5 element (low impedance dynamic) that will work straight into the Kenwood, Yaesu and ICOM rigs.  ICOM users MUST decouple the ICOM 8 volts!  Bob has included a 1 mfd. non polar capacitor in the kit for use with ICOM radios.
The kit includes the Heil XT -1 high impedance transformers, so that the microphone can be used with high impedance input vintage (like you Heath HW-101) transceiver.
The kits includes a custom mounting ring and cover foam to properly mount the HC 5 element within the D-104 microphone head!!


Gregory J. Beat:
Microphone connction for your Heathkit HW-101

The HW-101 WEB PAGE (31,000 kits were made)!

Patrick Bourgeois:
Thanks guys for all the help, got her working now, was missed wired, my fault just not familar with the 104.  But tried it after rewiring the 104 into a dummy load and am now getting meter action.

Thanks a bunch



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