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Rattletrapp
New member
Username: Rattletrapp

Post Number: 1
Registered: 2-2004
Posted on Wednesday, April 07, 2004 - 11:13 am:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

I have a tram d201/vox. I cannot turn the mic
gain up past the 2oclock position or I get a
hum when transmitting. I have tried different mics, Ive even tried keying the radio with no
mic and still get the hum.if i turn the mic gain
back to 1oclock the hum dissapears i need to be able to turn it up for that big booming tram
audio. Please help. thanks:Rattletrapp.
ps: i have already nuetralized the finel tube.
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Kc0gxz
Advanced Member
Username: Kc0gxz

Post Number: 711
Registered: 3-2003
Posted on Wednesday, April 07, 2004 - 11:46 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Rattletrapp

Sounds to me as if you have some electrolitic capacitors on the way out. This is to be expected on old radios such as yours. Replace them all. They're common and a whole lot cheaper than tubes. You'll probably find what you need at RatShack.

This is an old radio and it's not uncommon for electrolitics to dry up. Actually, they are nothing more than filters. What you are hearing is an A/C hum and those old electrolitic capacitors are no longer filtering that hum.

Jeff, kc0gxz.
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Tech833
Moderator
Username: Tech833

Post Number: 621
Registered: 8-2002
Posted on Thursday, April 08, 2004 - 2:41 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Sounds like some leaking caps in the audio amp section. Very common.

I have radios from the late 20's through the late 30's that work like new. Not one of them has a single original capacitor in them.

For a quick education on old tube radios and how to keep them running forever at maximum performance, see the antique radio site. They have a forum with some real smart people on it. Do a Google search for antique radio forum. It's the first site that pops up.
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Rattletrapp
New member
Username: Rattletrapp

Post Number: 2
Registered: 2-2004
Posted on Thursday, April 08, 2004 - 3:40 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Thank you for the info, guess i will be doing
some freshening up on the old tram.
well its back to the old soldering iron for me.
thanks again guys.
Rattletrapp.
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Tech833
Moderator
Username: Tech833

Post Number: 625
Registered: 8-2002
Posted on Thursday, April 08, 2004 - 8:11 pm:   Edit Post Delete Post    Move Post (Moderator/Admin Only)

Find someone in your area that restores antique radios for help. Not only will they probably have a ton of experience and the right parts for you, but they will also likely have the test gear to get your radio aligned and working better than new.

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