Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > Rectangular Screen Tube Televisions

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #1  
Old 04-03-2017, 03:10 PM
LADR's Avatar
LADR LADR is offline
Местное и дх радио
 
Join Date: Mar 2017
Location: Birmingham, AL
Posts: 189
Zenith 25MC36 color/sound problems

When i got this zenith home and fired it up, it had no sound or color. I got this set in a trade from dave and he told me the color had gone out while he still had it. I told dave about the no sound problem and he said that the sound was working before I took it home. I checked the audio output tube and tested a-ok. So any help with the two problems will be appreciated.
Reply With Quote
  #2  
Old 04-03-2017, 06:04 PM
TUD1's Avatar
TUD1 TUD1 is offline
TheUniversalDave1
 
Join Date: Jan 2014
Location: Birmingham, AL
Posts: 1,611
About the no color, I might try taking the chassis out of the set, and trying to do a visual inspection of the tube sockets. I remember before I changed the 6JH8's, the color was working, but with the new ones, there was no R-Y or B-Y. When I put the old tubes back in, one of the demodulators was working, I don't remember which one. About the no sound issue, I don't know what's going on. Maybe inspect the wires coming from the audio output transformer?
__________________
"If you wish to make an apple pie from scratch, you must first invent the universe." -Carl Sagan
Reply With Quote
  #3  
Old 04-03-2017, 07:18 PM
Zenith26kc20's Avatar
Zenith26kc20 Zenith26kc20 is offline
VideoKarma Member
 
Join Date: Apr 2009
Location: New Orleans
Posts: 824
Going to sound strange, but my 25MC33 chassis has had a couple of intermittants caused by connections (solder tabs) on the tube sockets. The filaments go out when the connection has problems. I looked over all connections on the demod tubes and found problems. Also, lightly pull on the wires going to the tube sockets. The soldering zenith used sometimes missed a connection and over the years, the connection oxidized and the tube went out.
Do you hear anything with the volume control at maximum? Also, check the plate resistor on the burst tube. The original will fail if the tube gets gassy.
Reply With Quote
  #4  
Old 04-03-2017, 08:11 PM
LADR's Avatar
LADR LADR is offline
Местное и дх радио
 
Join Date: Mar 2017
Location: Birmingham, AL
Posts: 189
Me and my stupid self didn't check the dern speaker plugs, so i did and found that the speakers were UNPLUGGED!
Reply With Quote
  #5  
Old 04-07-2017, 06:41 AM
LADR's Avatar
LADR LADR is offline
Местное и дх радио
 
Join Date: Mar 2017
Location: Birmingham, AL
Posts: 189
Well after some tinkering, i got decent color, green is very dominant while red is not really there.
Reply With Quote
Audiokarma
  #6  
Old 04-08-2017, 07:59 AM
DavGoodlin's Avatar
DavGoodlin DavGoodlin is offline
Motorola Minion
 
Join Date: Aug 2011
Location: near Strasburg PA
Posts: 3,403
I have a *BUNCH* of PF reporter articles on the 25MC36. Since I this same chassis in a combo set, Im motivated to research. Ill scan and post them here. This thread title makes a great search term.
__________________
"When resistors increase in value, they're worthless"
-Dave G
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 10:24 AM.



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