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 02-04-2015, 04:05 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
is this a U45 or an RCA clone?

U45 crt bias pot adjusts the G1 where the RCA adjust the cathodes.
Reply With Quote
  #17  
Old 02-04-2015, 04:05 PM
timmy's Avatar
timmy timmy is offline
VideoKarma Member
 
Join Date: Jan 2011
Location: ferndale ny
Posts: 3,504
the only way to get a picture or anything on the screen is with the bias maxed and still dark. bias ccw nothing on screen..
Reply With Quote
  #18  
Old 02-04-2015, 04:07 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
in that case I would try a new video out tube for starters.
Reply With Quote
  #19  
Old 02-04-2015, 04:07 PM
timmy's Avatar
timmy timmy is offline
VideoKarma Member
 
Join Date: Jan 2011
Location: ferndale ny
Posts: 3,504
i dont know if its the 45, 5 -45 -5 is stamped on the chassis its a gold color chassis if thats any give away.
Reply With Quote
  #20  
Old 02-04-2015, 04:08 PM
timmy's Avatar
timmy timmy is offline
VideoKarma Member
 
Join Date: Jan 2011
Location: ferndale ny
Posts: 3,504
it may be a clone because the rca 16 and 16x chassis uses a 12by7 but this one uses 12gn7
Reply With Quote
Audiokarma
  #21  
Old 02-04-2015, 04:12 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
if that does not help trace from the bias pot to a 220 resistor and a .22 cap. the resistor should be isolated so you should be able to check in circuit. You will need to lift a leg of the cap and test with an old school cap tester for leakage.
Reply With Quote
  #22  
Old 02-04-2015, 04:13 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
Its not a clone if the bias pot wiring is as described (bias adj the cathodes of the diff amps, thereby the G1's) close but not a clone

oh and check the 27k power resistors in the plate circuit of the diff amps, should have 410v on one side.

Last edited by DaveWM; 02-04-2015 at 04:23 PM.
Reply With Quote
  #23  
Old 02-04-2015, 04:17 PM
timmy's Avatar
timmy timmy is offline
VideoKarma Member
 
Join Date: Jan 2011
Location: ferndale ny
Posts: 3,504
g1 , solid colors the bias adjusts the voltage. and the bias pot is mounted on a board and there are resistors on that board and i checked all of them so it may be under the chassis, wish i had a schematic...
Reply With Quote
  #24  
Old 02-04-2015, 04:19 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
just look for a 220 resistor off the bias pot.
Reply With Quote
  #25  
Old 02-04-2015, 04:20 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
look for a 3.3 meg resistor that goes to one side of the user brightness control
Reply With Quote
Audiokarma
  #26  
Old 02-04-2015, 04:21 PM
timmy's Avatar
timmy timmy is offline
VideoKarma Member
 
Join Date: Jan 2011
Location: ferndale ny
Posts: 3,504
there is one 27k high watt resistor 405 one one side and 244 on the other, and tests perfect. that 220, ohm or k.
Reply With Quote
  #27  
Old 02-04-2015, 05:31 PM
timmy's Avatar
timmy timmy is offline
VideoKarma Member
 
Join Date: Jan 2011
Location: ferndale ny
Posts: 3,504
the 220 ohm resistor on one end of the bias pot is fine. the .22 cap near the diff amps checks lower in capacitance then another good one i have but its good. it will be very difficlut to reach the bright pot to see if it has a resistor on it. well there is no resistor on the bright pot and without a schematic it will take for ever to find because this thing is a combo and all controls are on one side and has long wires with no plugs to detach from the chassis, omg...

Last edited by timmy; 02-04-2015 at 06:06 PM.
Reply With Quote
  #28  
Old 02-04-2015, 07:36 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
Quote:
Originally Posted by timmy View Post
there is one 27k high watt resistor 405 one one side and 244 on the other, and tests perfect. that 220, ohm or k.
lets stick with this for a bit, the 244 should be fed thru a 100k ohm to the G1, and should not be dropping to the 160ish you mentioned before, find the 100k resistors that have one end on the G1 and the other to the 405. Something not right, the 244 should be at G1 as well, there should not be any loss across the 100k resistors in the G1 circuit.
Reply With Quote
  #29  
Old 02-04-2015, 07:40 PM
DaveWM DaveWM is offline
VideoKarma Member
 
Join Date: Feb 2009
Location: Orlando FL
Posts: 5,607
looking from the rear of the set
chroma board
left side
back of board
look between the tube in the corner and a exposed coil for the resistor.
Reply With Quote
  #30  
Old 02-05-2015, 09:42 AM
timmy's Avatar
timmy timmy is offline
VideoKarma Member
 
Join Date: Jan 2011
Location: ferndale ny
Posts: 3,504
ok there was 3- 27k resistors and they are all ok and there is a 100k resistor at each g1 wire and they too are good. and also one other 100k also good.
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 08:41 AM.



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