Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > Early B&W and Projection TV

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #16  
Old 02-03-2017, 08:24 AM
broadcaster broadcaster is offline
VideoKarma Member
 
Join Date: Mar 2016
Location: Kentucky
Posts: 148
Be sure to check the string of 6.8 meg resistors in the HV supply. Those were a problem for changing value.
Reply With Quote
  #17  
Old 02-03-2017, 10:49 AM
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
The more I see the more I kick my self for not making an offer when I had the chance...I did not want to try to make a new offer-up account at work.
__________________
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
  #18  
Old 02-04-2017, 10:52 AM
Crist Rigott Crist Rigott is offline
VideoKarma Member
 
Join Date: Oct 2015
Location: Waxahachie, TX
Posts: 1,506
Guys,
I've scanned the Riders info on this TV. It's from Riders TV 1 pages 44 thru 75. I then enlarged the Schematic and Wiring Diagrams and made separate files for those whose size is 36x24 for us old geezers.

I've uploaded them on Dropbox.

The Manual is about 12megs and the Schematic and Wiring Diagram are about 1meg each.

https://www.dropbox.com/s/awm0knizur...anual.pdf?dl=0

https://www.dropbox.com/s/52cxfm9kln...36x24.pdf?dl=0

https://www.dropbox.com/s/ajfa53b9r9...36x24.pdf?dl=0
Reply With Quote
  #19  
Old 02-04-2017, 11:50 AM
M3-SRT8's Avatar
M3-SRT8 M3-SRT8 is offline
VideoKarma Member
 
Join Date: Oct 2007
Location: Worcester, Mass
Posts: 643
Quote:
Originally Posted by broadcaster View Post
Be sure to check the string of 6.8 meg resistors in the HV supply. Those were a problem for changing value.
Looks like there's been some repairs there already. But I agree. A problem area with 621TS's.
Reply With Quote
  #20  
Old 02-04-2017, 01:06 PM
dieseljeep dieseljeep is offline
VideoKarma Member
 
Join Date: Jul 2010
Posts: 7,562
Quote:
Originally Posted by dieseljeep View Post
It looks like someone eliminated the PM ion trap and used the resistor in its place.
I meant it the other way around! Subsituting a PM ion trap for the EM ion trap and using a resistor in its place.
Reply With Quote
Audiokarma
  #21  
Old 02-04-2017, 01:41 PM
miniman82's Avatar
miniman82 miniman82 is offline
First Light: 1952-2011
 
Join Date: Jun 2009
Location: Great Mills, MD
Posts: 4,159
Yes, the 7DP4's were rebuildable. I have a Dunbar rebuild in mine, couldn't have seen many hours either since it tests like brand new. That's in my blonde model, I still need to pick up the mahogany one I won out of Connecticut recently.
__________________
Evolution...
Reply With Quote
  #22  
Old 02-06-2017, 08:23 PM
Crist Rigott Crist Rigott is offline
VideoKarma Member
 
Join Date: Oct 2015
Location: Waxahachie, TX
Posts: 1,506
Just a quick update. I ordered what I need from Just Radios, Digikey, and eBay. Tomorrow I'll enlarge the schematic and Wiring Diagram/Parts Placement drawing.
Reply With Quote
  #23  
Old 02-07-2017, 06:12 PM
Crist Rigott Crist Rigott is offline
VideoKarma Member
 
Join Date: Oct 2015
Location: Waxahachie, TX
Posts: 1,506
I got the schematic and Wiring/Parts Placement Diagram enlarged to 24 x 36. Just right!

I then started to work on the chassis. It is bit grimy and it has a layer of white corrosion all over. I think the plating did its job! To clean the chassis right, I decided to pull what I could off the chassis.

I pulled the yoke, the big resistor in the HV cage, HV cage, flyback, and HV rectifier tube and mount, and the resistor cage.



The big resistor had opened some tome ago and was replaced by 2 10K 20W resistors.


Here is a picture of the bottom of the socket from the 1b3GT HV rectifier tube.


While removing the resistor heatsink cage I found a wire that had barely been soldered on to one the resistor's terminals!


I'll have more pics later. Lots came off the chassis.
Reply With Quote
  #24  
Old 02-07-2017, 09:24 PM
Gregb Gregb is offline
VideoKarma Member
 
Join Date: Jul 2014
Location: Edmonton Alberta Canada
Posts: 548
Hey Crist, if you look closely it almost looks like they were soldered correctly at some point in time but the resistor had gotten so hot the solder has run down and has formed a drip on the bottom end of the terminal.

Gregb
Reply With Quote
  #25  
Old 02-07-2017, 09:31 PM
Crist Rigott Crist Rigott is offline
VideoKarma Member
 
Join Date: Oct 2015
Location: Waxahachie, TX
Posts: 1,506
Quote:
Originally Posted by Gregb View Post
Hey Crist, if you look closely it almost looks like they were soldered correctly at some point in time but the resistor had gotten so hot the solder has run down and has formed a drip on the bottom end of the terminal.

Gregb
Yeah, I can see where you'd think that. But the terminals are shaped like that! I have no reason why.
Reply With Quote
Audiokarma
  #26  
Old 02-07-2017, 10:41 PM
Crist Rigott Crist Rigott is offline
VideoKarma Member
 
Join Date: Oct 2015
Location: Waxahachie, TX
Posts: 1,506
Here is a picture of the chassis as of right now. I'm going to install the yoke support so when I work underneath, it'll sit on the support and protect the IF Cans. I also cleaned and masked off the sockets to protect them while cleaning.



Here is a close up of the area where the support was screwed to the chassis. It is a good indicator of how dirty the chassis is.

Reply With Quote
  #27  
Old 02-08-2017, 11:26 AM
Crist Rigott Crist Rigott is offline
VideoKarma Member
 
Join Date: Oct 2015
Location: Waxahachie, TX
Posts: 1,506
I started on cleaning the chassis. I'm using a green colored cleaner that the wife uses as a general purpose cleaner, and a fine grit Scotch-Brite pad. Then I followed it up using the cleaner and 000 steel wool. Then a wiping down using WD-40. Cleaned up nice.

Anybody know the name of the stuff that you wipe on and it protects the bare metal?

I've got my work cut out for me for the rest of the day.

Reply With Quote
  #28  
Old 02-08-2017, 03:12 PM
bandersen's Avatar
bandersen bandersen is offline
RCA 741PCS
 
Join Date: Mar 2009
Location: Chicago, IL
Posts: 8,085
I use Boeshield on bare metal
__________________
Here are my Vintage Radio & TV YouTube Channel and Photo Gallery
Reply With Quote
  #29  
Old 02-08-2017, 06:18 PM
Reece's Avatar
Reece Reece is offline
VideoKarma Member
 
Join Date: Jul 2004
Location: Cleona, PA
Posts: 2,178
Steel wool can work havoc if the fine wires get into things. Inspect closely and be sure they're not in there.
__________________
Reece

Perfection is hard to reach with a screwdriver.
Reply With Quote
  #30  
Old 02-08-2017, 07:54 PM
Crist Rigott Crist Rigott is offline
VideoKarma Member
 
Join Date: Oct 2015
Location: Waxahachie, TX
Posts: 1,506
Quote:
Originally Posted by reece View Post
steel wool can work havoc if the fine wires get into things. Inspect closely and be sure they're not in there.
10-4
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 01:28 PM.



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