The AM Forum

Gentlemen:
     Anybody here try the RB Micro replacement parts to repair the D-104? At $25 it looks good as long as it sounds good. My D-104 has a dead element. Any ideas?   ---Marty, KK4RF---

Check ebay for old beat up D-104's.....
My prize D-104 was won for 12 bucks.  It was in AWFUL cosmetic shape.  Pitted chrome and bad paint on the base.  But a little TLC and it looks better than new!  The element is great!  It's an unamplified, no ptt on base or stem.  Just as plain as you can get but it sounds really good going into the 12ax7 audio front end.

I followed some of the tips found on http://www.k3hkr.com/D104_repair.html (http://www.k3hkr.com/D104_repair.html)

Diet Pepsi rubbed into all the chrome de-pitted it great!  It's like magic! (the secret is the phosphoric acid and go with diet so you don't have sugars)

Mothers Chrome and Mag polish restored all the luster.  Sanded, primed and spray painted the base with Rust-o-leum Hammered Gray and it looks original.  That RB micro has felt for the bottom cut and ready to apply.

Point is, cheap old beat up D-104's on Ebay just might yeild you an authentic HiZ Astatic crystal element.  I simply would rather one instead of these "replacements" that are out there now.

John,
     Thanks for the tip and the helpful link. I'd like to repair the one I've got with a new element if possible. I've heard that Radio Shack used to sell cheap electret mics and wondered if anybody had used one of those into an old D-104. Think I'll check Radio Shack's website. Thanks again.---Marty, KK4RF---

Marty,

Check with Omnitronics. see info below. They used to sell the elements, but that was six years ago.

Jim
WD5JKO


> -----Original Message-----
> From: D Gregg [mailto:dgregg@omnitronicsllc.com]
> Sent: Monday, January 20, 2003 9:30 AM
> To: Candela, Jim
> Subject: Re: D104 Mic element needed
>
>
> Jim
> We sell the PMC320 crystal elements for $19.99 plus $7.00 shipping.
>
> Duane Gregg
> Senior Technician
> Omnitronics
> 440-593-1111 ext.212

Jim
     Thanks for idea. I'll give Omnitronics a call this week.
               ---Marty, KK4RF---

Most of those little mic cartridges don't come anywhere near a good D-104 hooked up to the right audio amplifier.

Many sound pretty bad.

If you google around enough freq response charts are out there.

Gentlemen,
     It is with much chagrin that I report that my D-104 microphone has not been dead all this time, but in fact was only hooked up wrong internally. This mic had been given to me with an improperly wired plug. I hadn't considered this before now. I got into it, hooked it up to my Globe Scout with clip leads into the base and it seems to work OK presently. I now need to get a plug for the end of the cable.
     Anyway, thanks for all the help. Wish I'd looked before I leapt!---Marty, KK4RF---

STill, it's good info.

Did you get ahold of Omnitronics anyway?
Several others might need replacement cartridges.

That's great Marty after all.  It makes me wonder how one can test a D-104s xtal cartridge without just putting it live in a circuit.  I ask because I was given a REALLY bad shape D-104 by someone who found it in an actual flea market, knew I was into radio so they picked it up for me.  It's wired for some 8 pin probably cb transceiver.  Would putting an AA battery across the xtal make it put out static noise like on a small speaker?  Moreover, would this damage it?  What about an ohm check... what should we see? Several million ohms?  I would think that reading might not necessarily mean it's all good.  Aw the heck with it, I'll just pull the head and sub into my good non-amplified D-104 stand and see... but what if i didn't have that option?  Doh, I should just scope it and look for good audio on the scope.

Gentlemen:
     I didn't call Omnitronics although I did look them up on Google. It's also from Conneaut ,Ohio, hence I suspect that must be a company that took over Astatic.
     I'm ordering a couple of the 1 pin amphenol-type  connectors so that I can hook up the D-104 to my Globe Scout and my newly-acquired Hallicrafters HT-40. I can then compare the old Turner 350-C hand mic with the D-104.
     I'm not certain what the D-104 element should read on a VOM. It has a high impedance element, but that's impedance and not necessarily resistance. I'm certain that somebody reading this posting could give a good answer on this question.
     Actually, the way I tested my D-104 was by clip-leading into the base of the mic, and connecting the leads to the mic input on the Globe Scout. I then turned on the transmitter into a dummy load and I watched the audio waveforms  on my newly-repaired Heath SB-614 scope/monitor.  Things looked good. I'm not certain how it will sound on the air yet, however, as my antenna is on the fritz. That's a project for another day.
     Thanks to all who've replied. I really learn a lot by reading what's on this website. It's one of the best on the net.
                                      ----Marty, KK4RF---

Mouser stocks some replacement crystal elements that some are buying and remarketing with a 5X mark-up.  They sound pretty good.  Catalog page link:

http://www.mouser.com/catalog/catalogUSD/640/1823.pdf

The 25LM024 Kobitone is what most folks use.

I picked up a D-104 at the flea market a few years ago.  The mic looks pretty good and works but I am wondering if there is any way you tell if the mic has the authentic HiZ Astatic crystal element?

Jerry/W8UJX/CA

Here is a pic from http://www.k3hkr.com/D104_repair.html (http://www.k3hkr.com/D104_repair.html) site.  The tin covered diaphram in the center of the inside of the head is a D104 cartridge, replacements do not look like that at all.

Try Amateur Electronic Supply in Milwaukee.

I bought a Astatic element from them 2 or 3 years ago. Who knows what they've got in the back room..

Thanks John,

Looks like I have the original Astatic xtal element.  The wind sock was firmly attached to the element but I raised one end enough to see the element.  In addition, there was a label on the back of the element holder that read, “Made by Brush Development Co. or The Astatic Corp”. 

Jerry/W8UJX/CA

KI4ES,
     I didn't see your name. Thanks for the Mouser link. That particular element has a 9,000 ohm impedance. Is that enough for tube transmitter like a Globe Scout or Hallicrafters HT-40?
     Thanks again to everyone.
                                      ---Marty, KK4RF---

The Kobitone elements are not a suitable replacement for a genuine D-104 element.

They will "work" but don't expect good tone like you get from a properly terminated healthy D-104.

If you spent a lot of time in the artillery please disregard this post.

I have heard the original Astatic element provides the best response.
That's the reason for my original post.
Tnx,
Jerry/W8UJX/CA

Hi All,

 I wonder if anyone called that number I posted at Omnitronics? Yes that was in 2003, and the company webpage switches to another, but that gentleman who I posted his number and extension might still be there.

 you folks might laugh, but I dropped my D104 many years ago, and the Mic was shot, low output and severe distortion. So I said, what the heck, and I took the darn thing apart. I used a razor blade around the outer edge of the foil diaghram, and broke the glue seal at the middle rod. The crystal element was intact. The inner rod, or piston was as I recall (been 20 years now) glued at each end. I had no glue (looks like glyptol would do), so I used hot candle wax. Yes hot candle wax at each end. All I had that night. Then I found some gasket sealer and glued the diaghram back on. Then more wax at the center to seal the rod to the diaghram.

  Did it work? Hell yes!! It not only worked, but it sounded pretty good too. Then the following summer the garage got hot as heck (Texas summer), and I suppose the wax melted. Give it a try, YMMV.   :P

Jim
WD5JKO

If I recall correctly, there was an article in Electric Radio about repairing the elements just that way.  I have the impression that the stuff is actually a hard wax rather than a glue.

Somewhere, on one of the other forums or maybe a different topic here, a bunch of people were complaining that the "replacement" D104 cartridges on eBay are not close to genuine but rather Oriental telephone earpiece elements bought from Mouser and marked up.  And that they do not sound as good.

Putting something else into the D104 would just result in a D104 stand and holder retaining something unrelated.  Sometimes that can sound pretty good, such as some of the electrets, but it's not a D104 anymore!

Even Heil has a replacement element but it's not anyting like the D-104.  But it probably sounds okay.  Anyone ever hear one?

http://www.heilsound.com/amateur/products/parts/d104.htm (http://www.heilsound.com/amateur/products/parts/d104.htm)

that looks lke a little condenture mic. I would question itz frequency responce with that little hole.

I just did a little more research on it and it's their HC-5 mic element.  Good to go for "Modern rigs" but if you have a vintage rig they do include an XT-1 High Impedance transformer.

I don't think old beater D-104's are that difficult to find at ham fests and even ebay.  I've always had good luck with them having intact, good original xtal cartridges.

John,
     I did check ebay the other day and there were tons of D-104s up for bidding on. That may well be the best approach. Hopefully my old D-104 will hang in there.
                 ---Marty, KK4RF---

I just got done repairing my d104.  The diaphram was all dented up, the wax was loose going to the crystal, and the diaphram was loose going all the way around because of the glue being dryed up.  I used an exacto knife to get the non dryes glue off around the diaphram.  Then I straightened out the element and glued the crystal back down(It has little plastic legs) MC-320 element.  used super glue for the element and remelted the wax on the "stick" going to the crystal.  If that is missing you can probably use wax from a candly, I used a lighter to melt it.  I still have yet to see how it works though

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

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

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

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.

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

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

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?

 

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,

"  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

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.

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

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

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

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

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.

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


(http://www.eecis.udel.edu/~hanavin/chuck/w3fjj/d104.jpg)

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..

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.

it didnt work

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

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

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