Astatic D-104 repair

[WD5JKO]

Nathan,

    Let us know how that repaired mic element worked out. As I recall it took more than one attempt for me to get mine going. Of course if the crystal element is damaged, then the effort will be impossible.

All the best,
Jim WD5JKO

[W8UJX]

I would also be interested in knowing what you guys think would be the best way to repair the cord.  The cord on my mic is so bad I need to replace the whole thing.

I was thinking of using a piece of RG-174 coax (about 6 feet) long for the element and a piece of #22 stranded, insulated wire for the Push to Talk.  Then put that whole thing inside a piece of RG8X coax that has the center conductor (not the shield) removed.

What say you guys?

Jerry/W8UJX/CA

[W1GFH]

Mogami makes some nice, flexible cables sold by the foot in electronic supply stores, 4 conductor, 2 sheilded, etc.

[Dave K6XYZ]

I use the Heil mic cable on my D-104's. It's very flexible and available without messing around for a day or two trying to make something work.

[KX5JT]

Yes I had purchased 20 ft of the Heil cable and use it for all my mic needs.  GREAT STUFF!

[NR5P]

hopefully it's not.  my uncle (who i got the mic from) said it used to work.  but it sat around a long time after that...I'll know in a while I got an ORIGINAL mc-320 that has not been used off of ebay.  NOS.  If I have any trouble im using it.  The guy had a few for buy it now 25.00.  I asked him if he has anymore and I will let you know.  I have a feeling it'll be ok unless something is wrong with the crystal.  I sure was careful though

[w5omr]

yeah, I know it's a dead thread, but it came up in a Google Search.  I value the opinion of the Brain trust here.  So, here goes...

The D-104 cartridge has a small piece that sticks up through the thin tin/aluminum.  I've got two dead elements here, so figured there's nothing more I could do to damage them, so took 'em apart and exposed the element.

What I found, on both elements, is that if I tap on the center, there's still audio that goes down the line.  I then gently 'rocked' the center pin back and forth and it seems as if it's loose from the goop that adheres it to the diaphragm.  Before I do anything else, I'm asking...  would a very light coating of maybe corona dope, or some thin liquid rubber applied over that center bring the element back to life?

 

[WD8KDG]

womr,

First make sure the crystal element is still secured to the frame. The two diagonal corners need to be glued. Where the "thingy" sticks through the diaphram, looks much like sealing wax to me. Try a hair dryer to remelt the wax to make a bond between the diaphram and "thingy".

Craig,

[KB2WIG]

"  yeah, I know it's a dead thread, "

Other than the smug ones, most of the radios ( and ops)  here are older than the internet.... Whatts wrong with reviving an old thread if you have some input?

klc

[k4kyv]

I remember the moderators had a severe hang-up about that on QRZ.com.  Finally modified the software so that a thread automatically closes after something like 30 days. Seems to be a common issue on message boards. I guess it's like plastic radios; some people are interested only in the latest and the greatest.

[ke7trp]

Old threads are still good.   

I love Me a D104.  Recently I tried the k7Dyy processor board for the D104. This provides a 600 ohm output.  The T368 has a 600 ohm input. This worked better then I could have hoped.  Classic D104 sound with plenty of Drive for the T368.

I wired it to the Audio rack via a low impedance line for a test. Also matched perfect. Clear D104 sound into the modern tube preamp.  Just added a touch of bass and it was good to go.

A great little toy for guys like me that really cant stand "Studio" mics on booms.



C

[W9BHI]

I have used the RB Micro replacement element kits on many D-104's.
they sound just as good or better than an original crystal element.
Just my $0.02.

Don W9BHI

[NR5P]

I forgot to add that my element that i repaired works great.  Has good frequency response.

[VA3AEX]

In my modest shack I've tried the Heil HC-5 element and even with the transformer the output is way down from my D104 (and I did try reversing the transformer).  Also tried some of the replacement elements advertised on eBay and got consistent 'muffled' audio reports.  The mic that gives the best audio reports and output is a crystal mic from an old Ampro reel-to-reel deck.

As far as testing, I've used a O scope to check output but that's difficult to do at a 'fest!

Alex

[KX5JT]

I've bought OLD HORRIBLE looking D-104's off of ebay that had perfect crystal elements.  I've paid as little as 15 bucks for working mics.  I've restored these horrible looking mics very easily with diet pepsi and mother's mag and chrome shine. 

My favorite D-104 cost me 15 bucks shipped and I constantly get great audio reports with it on the Viking II that has been audio modified.

[W3FJJ]

Here's a pic of D104 I want to repair. It has bad bass response, and yes I have it looking into 10 meg ohm impedance.
I wonder does it come apart any more, can pull the cone off to see the other side? There glue dried up around the
outside rim of aluminum cone, does what does it glue to?, just wind screen or the metal case? I guess I'll try melting wax in center, but
it doesn't seem to cracked. Any suggestions will be appreciated..   Thanks-Chuck

[W3FJJ]

I remelted the wax with a heat gun, but when I tried d104 after that
output dropped considerably, and I didn't notice any better freq response.
I tried remelting it again, then i was getting no output, so curiosity got
me and I ripped the metal cone off.  Here's a pic of what crystal looks
like. I think I ruined the element now, cone is now all dented up.
Oh well I wasn't using the mic anyway, cause it always sounded tinny..

[w5omr]

I have, laying about, some "Super Corona Dope". 

I applied a single drop of this stuff to where the tab sticks up through the diaphragm.

It appears to have -just covered- the junction. 
Another 15 min of curing and I'll know if it worked or not.

[w5omr]

it didnt work

[KC4VWU]

Without having the right equipment, repairing a D-104 element is usually a crap shoot. The biggest problem is that the Rochelle Salts crystal is VERY heat sensitive. Apply heat directly to it and it's ruined... it WILL melt. All the pieces have to be securely mated together. The waxes they use to hold it all together and the way it is applied is the key.

Phil

[w5omr]

Anyone have any WORKING hi-Z xtal elements they wanna get rid of?

[flintstone mop]

Seems like the original or even a beat up D-104 is the sound we are looking for. What was so special about the original cartridge? Is it so simple we are missing something? Cuz it has the right sound for Amateur AM use, if terminated properly. Very pleasant low end and that nice rise in the mid-highs for clarity.
I'm surprised Heil couldn't copy it well.
Fred