Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > Antique Radio

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #1  
Old 08-08-2017, 08:15 PM
mr_fixer's Avatar
mr_fixer mr_fixer is offline
VideoKarma Member
 
Join Date: Jul 2007
Location: Tennessee USA
Posts: 494
Zenith X334w radio with electrostatic tweeter

Hey All!. I got this today and after some tube socket cleaning it works mostly.
This is the table radio in the Danish Moderne case. mostly works but has almost no high freq audio response. this has the small square electrostatic tweeter and no audio comes out of it.anyone have a schematic or know of what to look for to fix this?
Reply With Quote
  #2  
Old 08-08-2017, 09:47 PM
Celt's Avatar
Celt Celt is online now
Super Maude
 
Join Date: Nov 2002
Location: Paragould, Arkansas
Posts: 1,544
Check the power supply to the tweeter. Often it's nothing more than a few failed electrolytics that need replacing.
__________________

Let me live in the house beside the road and be a friend to man.
Reply With Quote
  #3  
Old 08-12-2017, 05:54 PM
teevee's Avatar
teevee teevee is offline
VideoKarma Member
 
Join Date: Feb 2011
Posts: 96
If you have DC voltage across the tweeter, it should (if the coupling cap is OK) work. If not, there are a few threads on the interwebs dealing with the Grundig/Saba/Emud/etc. German radios that use electrostatic tweeters, and how to revitalize them. I've had about 70% success rate rebuilding them.
Reply With Quote
  #4  
Old 08-13-2017, 09:18 PM
mr_fixer's Avatar
mr_fixer mr_fixer is offline
VideoKarma Member
 
Join Date: Jul 2007
Location: Tennessee USA
Posts: 494
Quote:
Originally Posted by teevee View Post
If you have DC voltage across the tweeter, it should (if the coupling cap is OK) work. If not, there are a few threads on the interwebs dealing with the Grundig/Saba/Emud/etc. German radios that use electrostatic tweeters, and how to revitalize them. I've had about 70% success rate rebuilding them.
I have B+ going to the tweeter through a resistor and there is a tap from the audio output tube going to the same side of the tweeter through a small value ceramic cap .005 mf the return side of the tweeter is only a .01 ceramic to ground which i would think would block the dc. so it kinda does have voltage yet it doesn't depending on the way you think about it. It doesn't look tampered with.
Reply With Quote
  #5  
Old 08-14-2017, 12:06 AM
Titan1a Titan1a is offline
VideoKarma Member
 
Join Date: Apr 2015
Location: Plattsmouth, NE 68048
Posts: 363
My equivalent Zenith K735 had a bad tweeter which I had replaced with a piezo tweeter. High frequencies are back.
__________________
Rick (Sparks) Ethridge
Reply With Quote
Audiokarma
  #6  
Old 08-18-2017, 12:16 PM
teevee's Avatar
teevee teevee is offline
VideoKarma Member
 
Join Date: Feb 2011
Posts: 96
Quote:
Originally Posted by mr_fixer View Post
I have B+ going to the tweeter through a resistor and there is a tap from the audio output tube going to the same side of the tweeter through a small value ceramic cap .005 mf the return side of the tweeter is only a .01 ceramic to ground which i would think would block the dc. so it kinda does have voltage yet it doesn't depending on the way you think about it. It doesn't look tampered with.
Curious, what does the schematic show? All the electrostatics I've worked on had a DC bias on them.. the return is usually to groune.
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 06:32 PM.



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
ęCopyright 2012 VideoKarma.org, All rights reserved.