Videokarma.org

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

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #16  
Old 09-15-2015, 12:02 PM
Kamakiri's Avatar
Kamakiri Kamakiri is offline
Administrator
 
Join Date: Jun 2002
Location: Buffalo, New York
Posts: 5,048
First thing I'd do is check the B+ resistors in the vertical stages. Your setup may be similar to this:


__________________
"Restoring a tube TV is like going to war. A color one is like a land war in Asia."
Reply With Quote
  #17  
Old 09-15-2015, 12:05 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,598
indeed B+ and BOOST which is where the plate of the multivibrator gets its voltage. The reason for checking the .1 is if its even a little be leaky it will drag the plate voltage down, effecting the height. I am guessing you have the height pot maxed out?
Reply With Quote
  #18  
Old 09-15-2015, 12:24 PM
Arcanine's Avatar
Arcanine Arcanine is offline
VideoKarma Member
 
Join Date: Jan 2015
Location: Lake Geneva, Wisconsin
Posts: 281
Quote:
Originally Posted by DaveWM View Post
indeed B+ and BOOST which is where the plate of the multivibrator gets its voltage. The reason for checking the .1 is if its even a little be leaky it will drag the plate voltage down, effecting the height. I am guessing you have the height pot maxed out?
Yeah. The height pot is cranked to max. And Vertical Lin. is cranked pretty high as well to get that much picture from the set.
Reply With Quote
  #19  
Old 09-15-2015, 01:00 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,598
yea so lack of height is the real issue, the linearity problem will likely resolve when you can set it correctly.

I would try in this order

check line voltage (should be at least 117ac)
check B+ voltage
if ok
try known good tubes in vert (multi and output)
if no change try each testing inbetween

check resistors mentioned esp the 48k or 68k from the boost to the height pot, this frequently drifts high.

check the screen and plate resistors per picards post

bridge the 100uf vert out cathode bypass

if still an issue comeback for more. My money is on the 100uf OR the boost resistor in series with the height pot. I would also recommend replacing the .1 elmenco's there are two of them, replace them both.

The pots could be bad but if the were I would think the adjustment would be jumpy and or not working. the best way to test a pot is to take it out of circuit and test with a analog meter. For now just hit them with some clean juice and work them some.
Reply With Quote
  #20  
Old 09-15-2015, 09:51 PM
Arcanine's Avatar
Arcanine Arcanine is offline
VideoKarma Member
 
Join Date: Jan 2015
Location: Lake Geneva, Wisconsin
Posts: 281
Okay so as a simple test, Tom was kind and provided me with the parts and tubes he'd removed from the set when he was working on it.

Just as a shot in the dark, I swapped out the 6JB5 tube and it did help a bit. The linearity is still off, but I don't have the set vertical height pot cranked to the max to fill in the screen, and the top isn't stretched out as much.

The bottom is still compressed, but the over all quality of the picture is better.

I decided to swap this particular tube, because I looked in the back of the set last night, and noticed it had a purple glow going on. The one I put in doesn't have that purple glow. I'm not sure what that glow is, but I have seen it before on 6LQ6 tubes inside of a Ham Radio RF Amplifier. When the amplifier was transmitting, the tubes would glow like that when they were driving RF.

I also did a very basic purity adjustment, and I was able to clean off that green splotch on the right side of the screen.

I also made the stupid newbie mistake and reached too far behind yolk assembly and got a shock/burn on one of my fingers. Whoops!
Reply With Quote
Audiokarma
  #21  
Old 09-15-2015, 10:44 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,598
yoke burns are PAINFULL, much worse than HV, more current available I suppose.

Just remember that that purity and convergence setup are effected by sweep so if you go thru the effort to adjust those before fixing sweep, you will prob just have to do it again when/if you get the deflection working.

process in this order AFTER the set has been on for 20 min to warm up.

full raster (vert and horz)
setup linearity with test pattern
purity best reds (yoke back/center red blob/yoke forward to best fill red)
center converge (dots) focus for sharpness and keep the brightness down
dynamic converge (cross hatch)
grey scale
Reply With Quote
  #22  
Old 09-16-2015, 12:37 AM
Arcanine's Avatar
Arcanine Arcanine is offline
VideoKarma Member
 
Join Date: Jan 2015
Location: Lake Geneva, Wisconsin
Posts: 281
Quote:
Originally Posted by DaveWM View Post
yoke burns are PAINFULL, much worse than HV, more current available I suppose.

Just remember that that purity and convergence setup are effected by sweep so if you go thru the effort to adjust those before fixing sweep, you will prob just have to do it again when/if you get the deflection working.

process in this order AFTER the set has been on for 20 min to warm up.

full raster (vert and horz)
setup linearity with test pattern
purity best reds (yoke back/center red blob/yoke forward to best fill red)
center converge (dots) focus for sharpness and keep the brightness down
dynamic converge (cross hatch)
grey scale
Yeah. With the set the way it currently is, I can't get a total convergence from it.

Because I didn't like how the tube looked, I swapped the 6JS6 Horizontal Sweep for a 6KD6 spare I had.

Another huge difference. It did not help the current issues but it did sharpen the picture up a ton. It always seemed slightly dim before and a little out of focus. The 6KD6 made a big difference.
Reply With Quote
  #23  
Old 09-17-2015, 06:05 PM
holmesuser01's Avatar
holmesuser01 holmesuser01 is offline
VideoKarma Member
 
Join Date: Jul 2005
Location: Asheville NC
Posts: 1,731
Overall, other than the linearity and the blueish screen, you've got a winner there.

When I used to set up the screen controls with the service switch, I'd bring up red first to be almost dim... I did mine in a darkened room... Then the blue to make the red line purple, and then the green to make the grey. That should get you close.

Forgot to say, turn the color and brightness all the way down first.
__________________
Bruce
Reply With Quote
  #24  
Old 09-21-2015, 10:36 PM
Arcanine's Avatar
Arcanine Arcanine is offline
VideoKarma Member
 
Join Date: Jan 2015
Location: Lake Geneva, Wisconsin
Posts: 281
Does anyone know what the difference with a 6JS6A and 6JS6C Horizontal Output is?

I didn't pay close attention to the letter and stuck in a C instead of an A. It works, but I wonder if that's why the tube it self acts weird until it warms up?
Reply With Quote
  #25  
Old 09-22-2015, 05:11 AM
Alastair E Alastair E is offline
VideoKarma Member
 
Join Date: Feb 2013
Posts: 79
If you haven't already, Defo worth replacing C5 and C6 in your vert O/P stage.

Leccy-lytics lose value and dry up over the years, and in vertical timebase have a pretty hard life.
Any high value resistors in Height and Linearity control networks are also suspect.

Poor vertical lock could be issues in the sync-separator circuit, look for bias resistors of around 2.2M (Common issue on a couple of UK Hybrid TV sets, guess much the same applies if you have a Transistor doing sync-sep in yours)

A tip that was told me when I started out as a Trainee 40 odd years ago for setting up Any color TV....

Get the picture as good/perfect on Black/White First, Then worry about color after--Or you'll chase your tail!
--Its worked out pretty darned well during the last 40 years for me--so there must be summit in it!
Reply With Quote
Audiokarma
  #26  
Old 09-22-2015, 10:49 AM
jr_tech's Avatar
jr_tech jr_tech is offline
VideoKarma Member
 
Join Date: Sep 2009
Posts: 3,773
Quote:
Originally Posted by Arcanine View Post
Does anyone know what the difference with a 6JS6A and 6JS6C Horizontal Output is?

I didn't pay close attention to the letter and stuck in a C instead of an A. It works, but I wonder if that's why the tube it self acts weird until it warms up?
The "A" version is rated at 28 watts dissipation, the "C" version is a little stronger, at 30 watts. Should work fine.

jr
Reply With Quote
  #27  
Old 09-22-2015, 01:43 PM
Arcanine's Avatar
Arcanine Arcanine is offline
VideoKarma Member
 
Join Date: Jan 2015
Location: Lake Geneva, Wisconsin
Posts: 281
Okay so per recommendation I am replacing the electrolytic caps in the vertical section.

I was able to get a couple from Chesters today but I have run in to a bit of an issue;

C5 has two sections in it that are rated at 475V, 50uF and 40uF respectively. Chesters only had caps that went up to 450. Same for Capacitor World.

Where would I source these from?
Reply With Quote
  #28  
Old 09-22-2015, 02:00 PM
miniman82's Avatar
miniman82 miniman82 is offline
First Light: 1952-2011
 
Join Date: Jun 2009
Location: Great Mills, MD
Posts: 4,118
I use Allied or Mouser, they usually have the Panasonic ones that fit into the old cans.
__________________
Evolution...
Reply With Quote
  #29  
Old 09-22-2015, 02:02 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,598
second mousers. get the tall skinny ones, 105c
Reply With Quote
  #30  
Old 09-22-2015, 02:05 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,598
did you check those resistors in the Boost to plate of the 6BA11, 330k and 470k? and order up that .1 1kv while you are at it.
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 06:56 PM.



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
ęCopyright 2012 VideoKarma.org, All rights reserved.