| Author |
Message |
    
Alan_doss
New member
Username: Alan_doss
Post Number: 3
Registered: 2-2005
| | Posted on Saturday, February 19, 2005 - 1:08 am: | 
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I have a Mint condition Robyn T-240-D 40 Channel Tube and Transister Radio, I received it without a Mic, Here is my Question if you can Help, I asked for Help to Wire a Mic to work with the CB, and it works Great, (Transmits Fine) But There is very little Modulation comeing from the Mic, It barely moves my Dosy Meter about 1 to 2 Notchs on the meter, and the S Meter on the CB jumps all the way Quickly to Maximun readout, What might could be the Problem? Thanks Alan. P.S. If you need more Information just ask either here or email me at my email address and I will try and Help the best I can, again Many Thanks for any Help from the GURU'S, Smile. |
Hotwire
Member
Username: Hotwire
Post Number: 94
Registered: 1-2005
| | Posted on Saturday, February 19, 2005 - 11:23 am: |
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Hey Alan I'm not a tech but have some knowledge here and there over 25 years. I'm a collector of vintage tube radios. From my experiences with tube type radios I have found to be worn out tubes to be 99% of all problems. |
Alan_doss
New member
Username: Alan_doss
Post Number: 4
Registered: 2-2005
| | Posted on Saturday, February 19, 2005 - 5:58 pm: |
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Thanks Hotwire, I will check the tubes, Alan. |
Tech833
Moderator
Username: Tech833
Post Number: 1005
Registered: 8-2002
| | Posted on Saturday, February 19, 2005 - 11:09 pm: |
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Hotwire,
Don't overlook the possibility that he has some leaky caps in that radio.
I restored a Teaberry 40 ch tube radio (looks exactly the same as the Robyn, possibly same schematic too). I found all the coupling caps were leaky. Once replaced, it takes very little audio to push the radio to 100%.
The radio still hasn't sold, it's still here. So, I can dig it out in a couple days and check on the mic wiring for you if you like. Email me. |
Alan_doss
New member
Username: Alan_doss
Post Number: 5
Registered: 2-2005
| | Posted on Sunday, February 20, 2005 - 1:58 am: |
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Thanks anyway paul on the mic wireing I will also check the caps along with the tubes, Thanks for the input guys, you all have been quite helpful, Alan. |
Airplane1
Intermediate Member
Username: Airplane1
Post Number: 293
Registered: 5-2004
| | Posted on Wednesday, February 23, 2005 - 7:34 am: |
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tech 833, You said the Teaberry is not sold yet, does that mean you sell them?
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Tech833
Moderator
Username: Tech833
Post Number: 1010
Registered: 8-2002
| | Posted on Wednesday, February 23, 2005 - 1:33 pm: |
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We cannot use the Copper forum for selling things. |
Airplane1
Intermediate Member
Username: Airplane1
Post Number: 294
Registered: 5-2004
| | Posted on Wednesday, February 23, 2005 - 7:02 pm: |
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Sorry, Did`nt mean to break the rules!!!
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Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 227
Registered: 9-2004
| | Posted on Wednesday, February 23, 2005 - 9:56 pm: |
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alan doss, what kind of mic are you wiring to that radio? tube rigs and solid state rigs often have different input impedences on the mics. you may be trying to wire a lo-z mic to a hi-z radio. your best bet is to get a mic from a radio of the same era. maybe someone on here can suggest a mic that is still manuafactured today that is compatible with tube radios.
i would also recommend retubing and recapping the rig. when they work right, those old tubers have some pretty hi-fi audio!
matt |
Coyote
Intermediate Member
Username: Coyote
Post Number: 116
Registered: 11-2004
| | Posted on Thursday, February 24, 2005 - 11:37 am: |
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I'm still trying to hunt down an original Teaberry desk mic for my Model "T". I currently have a low Z mic wired to it. It works, but like Kid said, modulation is low. Everyone I talk to say's it sounds ok, but it would probably sound a WHOLE lot better with the correct impedence mic. |
Tech833
Moderator
Username: Tech833
Post Number: 1012
Registered: 8-2002
| | Posted on Thursday, February 24, 2005 - 8:33 pm: |
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The Teaberry has transformer coupled audio. The mic impedance is not critical at all. |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 230
Registered: 9-2004
| | Posted on Thursday, February 24, 2005 - 9:58 pm: |
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tech833, does this apply to most tube cb gear? those of us who are into the vintage gear could use some clarification on this issue. like maybe, which mics manufactured today will work. although it sounds like you're saying that the impedence doesnt matter and the low modulation is something else.
matt |
Coyote
Intermediate Member
Username: Coyote
Post Number: 117
Registered: 11-2004
| | Posted on Thursday, February 24, 2005 - 11:14 pm: |
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Tech833, thats good to know, maybe thats why this newer handheld I'm using sounds ok to everyone. Still want an original Teaberry desk mic though. Got one?  |
Tech833
Moderator
Username: Tech833
Post Number: 1016
Registered: 8-2002
| | Posted on Friday, February 25, 2005 - 10:11 am: |
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The original Teaberry desk mic was an Astatic D-104 that was color matched (black and chrome) to the Teaberry radio and available only as a special option. Yes, I have one. However, it is not for sale. It has to stay with the radio (they are a pair) and whoever owns that radio someday will end up owning the mic also.
The base is black, and the round part on top is all black except for the grille and the screws. Rest is chrome.
Teaberry Model T's came with a hand mic according to my manual and Sams Photofact. |
