d104 mic element

[Lil'Yeshua]

take a voltage reading across your mic element when you key the mic, if you have voltage there 1-9v it might work,, take note of what wire is + and - . if you do have voltage across your stock element, id just disconnect your element and wire in the r/s element and give it a try, don't even have to mount the element or put the mic together, just wire the new element in and key it up and see what you get.

I tried that. The K40's element leads unplug from the socket. I plugged the R/S element both ways and it won't work. According to the schematic there's a 100 k ohm resistor between the element and the IC. The resistance might need to be changed. I have the VR pot adjusted on the K40 to 4 volts. That's for the 2n5458 transistor. I might have to experiment with the voltage level.
I did strum my finger on the pickup stylis on the K40 mic element and it's producing a sound on my 959's talkback. Also,if I whistle into the K40's element it will produce a sound on the radio. I have a bid on Ebay for the regular K40 stock mic. I hope it's got the same mic element.

 

[camaro1]

do you have voltage at the element when you key the mic,, you need voltage for the electret element to work.

if you don't have voltage at the element when you key the mic you will need a 1k-4k resistor from b+ to the + side of the element to supply some voltage to it

not good to just randomly put the element in and not even know what side is +, -

 

[Lil'Yeshua]

do you have voltage at the element when you key the mic,, you need voltage for the electret element to work

I tried that. Any voltage at that point will make the radio key up. I also tried a stock Galaxy hand mic element but no cigar. I wonder if the RB Micro element might work?
http://www.rbmicro.com/prodgfx/25LM022.pdf

 

[Lil'Yeshua]

I tried doing a solder bridge accross the broken part in this photo but I can once again only get an audio response through my radio if I whistle into it.
I think if I got a comparable mic cartridge I'll get it to work right again. Any pointers here?

 

[LaValle]

you can mount the element many ways, I found these round radioshack boards make it easy to mount, you place the element through the center holes and trim and bend over the pins, the board gives a nice place to solder the element and mic leads to, 1k resistor works fine and yes put the resistor just like the pic shows, no heat shrink needed

Hummm - Ive searched and searched but can't find the "pic", can someone repost it or tell me what a dumb ass I am and how I missed it? 73's LaValle

 

[tim mclaughlin]

radioshack $2.99 just add a resistor to the base to power up the element,, these work great have several of them being used now with these elements.

do a search, there is a couple other posts about these radioshack elements around here

this is not showing on a tug8

 

[Shockwave]

Are you using the K40 mic on a K40 radio? That mic is not readily adaptable to other radios. It uses a capacitor on the processor board that gets charged in receive and powers the mic in transmit. I can remember if you got long winded on these mics your audio would drop out towards the end of the transmission as the cap discharged. Just unkey for a second and it recharged. If you are using it on a K40 radio, check this cap to insure it is holding a charge when you transmit. They are old enough now that the cap could be bad.