| Author |
Message |
    
Pancake
Junior Member
Username: Pancake
Post Number: 30
Registered: 3-2002
| | Posted on Sunday, March 14, 2004 - 4:15 pm: | 
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hey all,
i bought this silver eagle and it isnt working right i got it from a swap shop so i took a chance but i want to get it working again.
the date of manufacture on it is 9/77 stamped on the wiring diagram on the inside of the cover.
i wired it up ,put a brand new battery in it and turned the mod pot up all the way and it talks like a stock mic.the mod pod functions because it changes the sensativity of the mic from tottaly cut off ,to very low.
i tried another known good battery and still the same...
i tried the head off my d-104(known good)and still nothing changed...the mic is in great shape but it appears that the bottom may have gotten wet at one point because when i went to put a new battery in the cover screws were corroded into the base(not bad,but hadnt been out in a while).
the board looks untouched,and all wires are hooked up.there is very little corrosion on the board,on a scale of 1-10 as far as the amt of corrosion on the board there is maybe .02 and it is just on the legs of a few components,but not all,it is barely even noticeable.
im guessing whatever has to do with the amplification of the modulation got wet and crapped out..
any help on what to test and how to test it would be much appreciated |
Tech808
Moderator
Username: Tech808
Post Number: 1815
Registered: 8-2002
| | Posted on Monday, March 15, 2004 - 12:29 am: |
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Ok here are a couple of thing's to try & check.
Clean the Contact's of the piano switches.
The turn Modulation pot all the way Open and Closed maybe 25 to 30 time's.
Also check it with a modulation meter and see what it is putting out.
Also Check Mic Head Wiring from where Mic head fits on, down thru the Stem to make sure all solder connection's are good.
Also check all wires to make sure they still have good solder connection's.
Lon
Tech808 |
Pancake
Junior Member
Username: Pancake
Post Number: 31
Registered: 3-2002
| | Posted on Tuesday, March 16, 2004 - 6:41 pm: |
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ok i cleaned the contacts.
i worked the pot like an employee at my workplace(a slave)lol
i dont have an external meter but going my the reading on the in radio meter(cobra 142gtl) at arms length and all the way tuened up on the mic and radio with me talking LOUD it goes up to what i would call 10 % and if i hold it directly in front of my face and talk in that same loud voice it goes up to just shy of the 100% mark
also checked every wire in this thing and all were soldered good ,tight,not corroded
a friend of mine who is blind but used to work in electronics repair walked me through a few basic tests and he said from the readings that i get with the multimeter the pot works like it should
it has got to be something on the board but i dont know what and i dont understand the wiring diagram on the base plate |
Jon666
Intermediate Member
Username: Jon666
Post Number: 120
Registered: 11-2003
| | Posted on Tuesday, March 16, 2004 - 7:14 pm: |
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mabey one of the amplifer transisters
are shorted out.i would replace them first.
at least check them. |
Kc0gxz
Advanced Member
Username: Kc0gxz
Post Number: 639
Registered: 3-2003
| | Posted on Wednesday, March 17, 2004 - 1:48 am: |
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Pancake
Jon666 gave some good advice. That was my second thought. I would have gone after the relays first but since that was already covered here, my thoughts turned to the 2 little audio amplifiers transistors.
If you can't find any original transistors, use a pair of 2SC-945s that you can find in almost any junked out radio. Take note of pins. Put them in the same way that you take the old ones out.
Lol. If it still doesn't work, put it on Ebay. You'll get a hundred bucks for it as long as it's in good shape and everything is there. Most people that collect those things don't even know if they work or not. Or care. One of the oldest Astatics that I own is a 1941 vintage Model T-3 on a G-stand. I think Lon owns one or two of them also.
Even though there are millions and millions of D-104s are out there, some people think they are worth a fortune. In a hundred years or so they just might be, but not in our lifetime.
Just my thoughts on the most popular and most cheaply made microphones ever built.
Jeff, kc0gxz.
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Pancake
Junior Member
Username: Pancake
Post Number: 32
Registered: 3-2002
| | Posted on Thursday, March 25, 2004 - 9:49 pm: |
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jeff,thanks for the reply,i will try and test those 2 "audio amplifier transistors" but before i can do that,can anyone here describe to me where they are or what they look like
thanks in advance,dave in n.y. |
Jp1116
Junior Member
Username: Jp1116
Post Number: 48
Registered: 5-2002
| | Posted on Friday, March 26, 2004 - 8:34 am: |
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You might want to check to see if there has been an L-PAD put in to lower the modulation. Some radios don't really need the amplifier in the mic and this will reduce the output so you don't overmodulate the radio. If you go to http://www.astatic.com and click on the "details" button on the Silver Eagle picture on the page it will describe an L-PAD and you can download a copy of the schematic. I tried to email these along with a picture of a transistor but it came back as not being valid. |
Pancake
Junior Member
Username: Pancake
Post Number: 34
Registered: 3-2002
| | Posted on Wednesday, March 31, 2004 - 9:39 pm: |
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checked on the l pad and it wasnt done to this one...the white wire runs direct to the contact and then from there to another thicker white wire that runs to a spot on the board |
