D-104 Death

[Mark Malcomb]

Hello Matt, I hope you are well. I got a problem I hope you can help me with. Both of my D-104 mics took a shit. I hope its not due to the extreme Arizona heat in my somewhat insulated garage. My mics will not show any modulation when I key up. I checked the batteries and used another radio to here any sound from both mics I get nothing. I fear the elements may have died. Is there any thing I can do to save them? If not can you give me some advise on the good replacement element that is reasonable without having to totally mod the amp board.
A few months ago I was shooting some skip from Oregon and I was told "sounded great and on frequency."
(38 LSB) Damn I fear the worst now that both do the same shit, I will owe you again for any help you can provide
I was so happy with the crystal elements, I hope I didn't fuck them up! If you got any input.
All my thanks to you Matt.
Mark.

PS This was a PM, I didn't realize there was a character limit, I guess all the input from you guys is a good thing. thanks in advance,,,,,,,,,,,,,,,Mark

 

[Tokin]

I have a crystal element from a working d104 that i took out to modify the head to a low impedance Dynamic element.
I have both for sale atm on ebay but would be willing to sell here also.
The Dynamic element i used was from an old school cobra coffin mic that was made in Japan. Ive never tried it on an amplified stand and im curious how it would sound. Im not sure if you would need to change the amplification board any.
I run my modified non amplified d104 thru my ur6qw eq/compressor and it sounds great.
I would say to open the head and check to see if youre geting power to the element when you key up and go from there.

 

[Tokin]

This is the Dynamic low z conversion

 

[Mark Malcomb]

Thank you buddy, I didn't check the voltage on the element when I key up. What should it be? Are your elements for sale on this site?

 

[Tokin]

I do not know the voltage. I dont have a transistorized stand here to test. Someone here may be able to help there. Yes the one crystal element is for sale but i dont want you to buy something you dont know if you need yet. Personally id rather sell it here than ebay but lets make sure thats the problem first.

 

[loosecannon]

Hi Mark,

Yes the heat can damage the elements, and if they were both in the same environment, that could explain why they both are acting the same way.

and with the weather cooling off, it is possible that the wax connecting the foil cone to the element at the center could have gotten hard and not be making good connection.

Just so i understand, you have two complete mics, and aren't just switching two heads to the same base right?

if this is the case, then there is a chance that the wax that connects the actual rochelle salt element to the foil cone has become loose.
although usually this results in a less than ideal sound and not so much no sound at all.

you can try waving a cigarette lighter around that wax at the center of the foil cone in order to soften it, and then GENTLY reform it around the little peg that sticks out the center. you can also try dropping a dab of bees wax on there instead.

just to be sure, you have tried a stock mic on the radios in question and confirmed that they are not the problem right?
best to listen on one radio and talk to yourself on another to confirm or deny modulation is taking place rather than relying on some other indicator that might also be bad.

try to think about what pieces of equipment you are using for both mics.
same adapter? same modulation meter? try to weed out some other piece of equipment being bad, as two mics exhibiting the exact same symptoms at the same time usually means they are not the real problem.

if you just need to confirm whether or not the elements are bad, and no amount of testing is getting you anywhere, you can send me just the mic heads, and i'll test them here on a known good D-104.

these could work for you, but no guarantees on sound quality. High impedance elements are getting hard to come by.
https://www.ebay.com/i/293840738640...8K9_bT631YozLa2Ov1YWsljmepNon50xoCx7oQAvD_BwE

LC

 

[Mark Malcomb]

Ok Matt,
Yes I have 2 complete D-104's that are acting the same way. I have 3 Washington's
My 3rd the D104's is dedicated to the Frankenstein radios that has power for the
mic from the radio. It does work. On the 2 failing mics, If I crank up the mic gain attenuator till it overdrives
and squeals and just back it off, I can hear the audio on another radio. The meter on modulation does not swing. 2 of the D104s work this way. The third one has those cheap Ebay WNy 29 dollar replacement for the first element that crapped out. I realize the crystal elements are high impedance however I don't know how high. If I check them with a meter can I verify if they're good? Sounds lame, I just don't know.
I have tried both failing mics on 2 different radios while monitoring the 3rd radio.
No swing on modulation. I have not tried putting the 1 working mics head on the failing stands. There is a little mod you have to do for that mic. I see this is a bit confusing to understand. It is early and I just got to work. May need more coffee!
Thanks Matt
Mark.

 

[Tokin]

Ok Matt,
Yes I have 2 complete D-104's that are acting the same way. I have 3 Washington's
My 3rd the D104's is dedicated to the Frankenstein radios that has power for the
mic from the radio. It does work. On the 2 failing mics, If I crank up the mic gain attenuator till it overdrives
and squeals and just back it off, I can hear the audio on another radio. The meter on modulation does not swing. 2 of the D104s work this way. The third one has those cheap Ebay WNy 29 dollar replacement for the first element that crapped out. I realize the crystal elements are high impedance however I don't know how high. If I check them with a meter can I verify if they're good? Sounds lame, I just don't know.
I have tried both failing mics on 2 different radios while monitoring the 3rd radio.
No swing on modulation. I have not tried putting the 1 working mics head on the failing stands. There is a little mod you have to do for that mic. I see this is a bit confusing to understand. It is early and I just got to work. May need more coffee!
Thanks Matt
Mark.

Heres what i found on testing

Unplug the D104 head from the stand. There are 3 pins in the head connector. The
2 close together are the mic element. Use a high impedance digital
meter, VTVM or oscilloscope connected to the 2 pins. Give a nice long
WHOOOOIE into the mic and you should get over 200 millivolts RMS on the
meter, or 500 mv peak to peak on the scope.

 

[Mark Malcomb]

Thanks I can do that when I get home..

 

[Tokin]

Thanks I can do that when I get home..

Let us know how that turns out.

 

[Tokin]

Well, i bought another D-104 this time an amplified unit so i can test the heads i modify on an amplified stand and perform some audio tests.
When i get it ill check if the crystal element is working. If so ill have 2.

 

[Mark Malcomb]

Cool, I just tested my mic at work. Looks dead. On the scope and my 6 1/2 digit meter.
I guess they could be dead. Wish I had a stock hand held. I wouldn't know how to get the right one for my radio. I know I am lame with radio gear

 

[Tokin]

Cool, I just tested my mic at work. Looks dead. On the scope and my 6 1/2 digit meter.
I guess they could be dead. Wish I had a stock hand held. I wouldn't know how to get the right one for my radio. I know I am lame with radio gear

We were all lame with gear at one time and i still am, thats why im here lol.
What radio are you wanting to use them on? I ask because i have a mic that sounds great on ssb. Its the Realistic 21-1173. Its amplified and uses 2 aa batteries. It uses the same amplification board and mic element as the Turner +3 desk mic so it sounds great and its Japan made. It's wired 4 pin cobra atm. I always got great audio reports on ssb with this one. You'll never have to worry about a crystal and wax element going bad. Otherwise hang tight and lets see what condition this other mic is in this week 8and i still have the other working element here too.

 

[Mark Malcomb]

I got a few 5pin Washington's. I always had great radio checks with The D-104's
On ssb got great checks saying right on freq.

 

[Tokin]

I got a few 5pin Washington's. I always had great radio checks with The D-104's
On ssb got great checks saying right on freq.

Ive used this realistic mic on numerous 148gtl's and 2950dx rigs using 4 pin adapters and never had a bad audio report.
Whatever you decide i have some stuff here that might help.