Videokarma.org

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

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #1  
Old 07-18-2013, 10:42 AM
oldtvsandtoy oldtvsandtoy is offline
Banned
 
Join Date: Aug 2009
Location: Clinton Township , Michigan
Posts: 285
aaa

aaa

Last edited by oldtvsandtoy; 02-05-2018 at 01:19 PM.
Reply With Quote
  #2  
Old 07-18-2013, 10:05 PM
bgadow's Avatar
bgadow bgadow is offline
VideoKarma Member
 
Join Date: Oct 2003
Location: Federalsburg, MD
Posts: 5,814
Have you looked at using modern diodes? I've heard plenty of stories about seleniums failing and stinking up the joint. I do have a handful of NOS and used seleniums but would have to check for the ratings.
__________________
Bryan
Reply With Quote
  #3  
Old 07-19-2013, 05:55 AM
oldtvsandtoy oldtvsandtoy is offline
Banned
 
Join Date: Aug 2009
Location: Clinton Township , Michigan
Posts: 285
aaa

Last edited by oldtvsandtoy; 02-05-2018 at 01:19 PM.
Reply With Quote
  #4  
Old 07-18-2013, 10:30 PM
Jon A.'s Avatar
Jon A. Jon A. is offline
Don't mess with Esther.
 
Join Date: Jun 2013
Location: Canada
Posts: 4,267
Yeah, the smell will get into your furniture as well.
Reply With Quote
  #5  
Old 07-19-2013, 02:45 PM
bob91343 bob91343 is offline
VideoKarma Member
 
Join Date: Nov 2010
Posts: 745
I find that the 1N4007 works for nearly all cases like this. You will also need a resistor in series with the diode, maybe 47 Ohms 2 Watts. 1N4007 diodes cost a few pennies each so buy a bunch for future use.
Reply With Quote
Audiokarma
  #6  
Old 07-19-2013, 08:52 PM
oldtvsandtoy oldtvsandtoy is offline
Banned
 
Join Date: Aug 2009
Location: Clinton Township , Michigan
Posts: 285
aaa

Last edited by oldtvsandtoy; 02-05-2018 at 01:19 PM.
Reply With Quote
  #7  
Old 07-19-2013, 09:34 PM
AdamAnt316's Avatar
AdamAnt316 AdamAnt316 is offline
Collector of heavy things
 
Join Date: Mar 2007
Location: MA
Posts: 140
Quote:
Originally Posted by oldtvsandtoy View Post
will that work for the .200a and .130 a?
1N4007 diodes can handle a full amp, so they should be more than enough to replace either of those.
__________________
Visit my site!

Stereo: Pioneer SPEC-4, Pioneer SPEC-1, Kenwood KT-7500, Dual 1219, Nakamichi BX-100, Pioneer PD-M60, Paradigm Studio Monitors
Reply With Quote
  #8  
Old 07-20-2013, 01:44 AM
kramden66 kramden66 is offline
VideoKarma Member
 
Join Date: Nov 2010
Location: Rockaway, NJ
Posts: 1,414
one 1n4007 for one selenium rectifier , one for the other , its pretty easy to do and more reliable since the nos ones would fail after a while anyway.

mike
Reply With Quote
  #9  
Old 07-20-2013, 10:53 AM
oldtvsandtoy oldtvsandtoy is offline
Banned
 
Join Date: Aug 2009
Location: Clinton Township , Michigan
Posts: 285
aaa

Last edited by oldtvsandtoy; 02-05-2018 at 01:19 PM.
Reply With Quote
  #10  
Old 07-20-2013, 03:55 PM
bob91343 bob91343 is offline
VideoKarma Member
 
Join Date: Nov 2010
Posts: 745
A resistor is needed. See my post above.
Reply With Quote
Audiokarma
  #11  
Old 07-25-2013, 03:10 PM
Electronic M's Avatar
Electronic M Electronic M is offline
M is for Memory
 
Join Date: Jan 2011
Location: Pewaukee/Delafield Wi
Posts: 14,758
Also not a bad idea to put a .01uF 600V film cap in parallel with the diode to reduce the increased switching noise inherent in modern diodes. It is called a snubber cap when used in this application IIRC.
__________________
Tom C.

Zenith: The quality stays in EVEN after the name falls off!
What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4
Reply With Quote
  #12  
Old 09-06-2013, 07:22 AM
Kamakiri's Avatar
Kamakiri Kamakiri is offline
Administrator
 
Join Date: Jun 2002
Location: Buffalo, New York
Posts: 5,109
We sure could use a good tutorial on replacing these. I'm diving into a Halolight that is going to need them, and I've never done it before. Even a simple diagram would work
__________________
"Restoring a tube TV is like going to war. A color one is like a land war in Asia."
Reply With Quote
  #13  
Old 09-06-2013, 07:42 AM
Username1's Avatar
Username1 Username1 is offline
Not sure how I got here.
 
Join Date: Dec 2009
Location: Orange County NY
Posts: 3,584
To begin with while you have a working selenium in place, measure the voltage drop across it, the current running through it, and the shape of the rectified signal. Use the current, and voltage drop to figure out what resistor to put there..... And the scope pic of the wave after it, when you put a cap across it, compare the new picture to the old one..... Call it engineering a solution.
__________________
Yes you can call me "Squirrel boy"
Reply With Quote
  #14  
Old 09-06-2013, 09:05 AM
Kamakiri's Avatar
Kamakiri Kamakiri is offline
Administrator
 
Join Date: Jun 2002
Location: Buffalo, New York
Posts: 5,109
In this case, this set probably hasn't seen a wall receptacle since the Nixon administration, if not before that.

I have to do a full recap on it, so let's assume for the moment that I can't do that
__________________
"Restoring a tube TV is like going to war. A color one is like a land war in Asia."
Reply With Quote
  #15  
Old 09-06-2013, 09:17 AM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
A couple things I do, if replacing selenium with silicon, I would leave a term strip setup for a B+ dropping (and fuse for that matter if it does not have one), then use a variac and start at about 90v see how the set behaves (this is assuming its working). if everything working check the B+ at the output of the rectifier to the sams check the current and get a ballpark figure for the dropping resistor using ohms laws, prob between 50 and 200 ohms. check your line voltage and fine tune the resistor to the correct B+
Reply With Quote
Audiokarma
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 06:59 AM.



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
©Copyright 2012 VideoKarma.org, All rights reserved.