Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > Solid State CRT Televisions

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #16  
Old 07-27-2018, 04:20 PM
zeno's Avatar
zeno zeno is offline
VideoKarma Member
 
Join Date: Mar 2013
Location: New Hampshire
Posts: 4,672
BTW for all.........
MOST horizontal outputs ( HOT's) from the late 70's on have a built in
damper diode & base resistor. The resistor goes from B-E & screws up
that reading. The damper diode will give a diode reading E-C one way
& wide open the other on the meters diode setting.

BTW #2
I lied ! I had ONE HOT open out of hundreds I found shorted. In a Zenith
custom series 25".

BTW #3
Quick check of HOT is ground meter & measure C to ground. If shorted
unsolder the HOT's C & retest. if no short its somethin else like FBT.
If the HOT is shorted the fun begins finding out why it did without
blowing parts.

73 Zeno
LFOD !
Reply With Quote
  #17  
Old 07-27-2018, 09:11 PM
Sealtest Sealtest is offline
VideoKarma Member
 
Join Date: Dec 2017
Location: Knoxville, Tennessee
Posts: 129
Quote:
Originally Posted by zeno View Post
Yup all modern colors have a DGS coil.
Set is unlisted in Sams. Look on CRT socket for a chassis ##
like K20. If not there look on main board. We can still go father
without a manual.

73 Zeno
LFOD !
According to the socket the model is "K-50".

The board has no number, but it does say "file name: CT513V". Is this something to do with the SAMS?

Also I should have ordered the STR30125 shouldn't I?
Reply With Quote
  #18  
Old 08-04-2018, 08:38 PM
Sealtest Sealtest is offline
VideoKarma Member
 
Join Date: Dec 2017
Location: Knoxville, Tennessee
Posts: 129
Got the parts in today and have a small issue. The new 2sd1555 reads the same as the old. I have not found any bad parts in that case, so I am not sure where to look next. I think maybe a cap went bad but so far all caps are in spec.
Reply With Quote
  #19  
Old 08-05-2018, 09:27 PM
Sealtest Sealtest is offline
VideoKarma Member
 
Join Date: Dec 2017
Location: Knoxville, Tennessee
Posts: 129
Found a bad resistor and replaced it. I did the power up procedure and the set did not go over an amp... at first. The raster was an odd rainbow mixed with the way a screen looks when it has bad caps (caps in the power and hv section are good). The screen was slowly flashing and causing the amp meter to jump between .8 amps up to 1.1 amps with each pulse. The set also smelled like a very warm tv but it smelled stronger so I am not sure if something is dying or what. The pulsing is the main concern since it was a bit unsettling.
Reply With Quote
  #20  
Old 08-06-2018, 10:00 PM
Sealtest Sealtest is offline
VideoKarma Member
 
Join Date: Dec 2017
Location: Knoxville, Tennessee
Posts: 129
Disregard. It is still drawing 1.5 amps.

Here is a picture of the screen though.

I have started recapping and testing every single part but nothing is bad so far so I guess I will have to check it all again. There is an IC chip of some sorts in the HV section. Maybe that could be the problem but it is unmarked.
Attached Images
File Type: jpg IMG-5750.jpg (63.7 KB, 18 views)
Reply With Quote
Audiokarma
  #21  
Old 08-07-2018, 03:24 PM
zeno's Avatar
zeno zeno is offline
VideoKarma Member
 
Join Date: Mar 2013
Location: New Hampshire
Posts: 4,672
Run for about 30 sec then unpower & feel the 2SD1555.
To hot to touch most likely bad FBT or rectifier off it.
If cool or a little warm turn up variac & see if things improve.
The amps sometimes fall as the AC volts go up.
Keep in mind the HOT can short again if not careful. My advantage
doing this was knowing what I could get away with !

73 Zeno
LFOD !
Reply With Quote
  #22  
Old 08-09-2018, 12:29 AM
Sealtest Sealtest is offline
VideoKarma Member
 
Join Date: Dec 2017
Location: Knoxville, Tennessee
Posts: 129
Quote:
Originally Posted by zeno View Post
Run for about 30 sec then unpower & feel the 2SD1555.
To hot to touch most likely bad FBT or rectifier off it.
If cool or a little warm turn up variac & see if things improve.
The amps sometimes fall as the AC volts go up.
Keep in mind the HOT can short again if not careful. My advantage
doing this was knowing what I could get away with !

73 Zeno
LFOD !
When I stop fighting with that trinitron project I'll try this.

I'm starting to wonder if something isn't getting enough power in the set. With the Samsung at 90vAC it looks like the trinitron screen at around 50ish volts. I'd suspect caps but they've all tested good so far. Dang TVs are a challenge compared to other electronics.
Reply With Quote
  #23  
Old 08-09-2018, 08:53 PM
Sealtest Sealtest is offline
VideoKarma Member
 
Join Date: Dec 2017
Location: Knoxville, Tennessee
Posts: 129
Quote:
Originally Posted by zeno View Post
Run for about 30 sec then unpower & feel the 2SD1555.
To hot to touch most likely bad FBT or rectifier off it.
If cool or a little warm turn up variac & see if things improve.
The amps sometimes fall as the AC volts go up.
Keep in mind the HOT can short again if not careful. My advantage
doing this was knowing what I could get away with !

73 Zeno
LFOD !
The transistor was cool to the touch and raising the AC caused the amps to go up. Then the screen started pulsing and an odd smell filled my shop. Something is giving off heat somewhere on the board. A laser thermometer really would come in handy probably.

I'm going to look through some case histories and see if any sets in the book have had the same issue or something close.
Reply With Quote
  #24  
Old 08-10-2018, 10:45 AM
dieseljeep dieseljeep is offline
VideoKarma Member
 
Join Date: Jul 2010
Posts: 7,562
Quote:
Originally Posted by Sealtest View Post
The transistor was cool to the touch and raising the AC caused the amps to go up. Then the screen started pulsing and an odd smell filled my shop. Something is giving off heat somewhere on the board. A laser thermometer really would come in handy probably.

I'm going to look through some case histories and see if any sets in the book have had the same issue or something close.
Feel the electrolytics and see if the main one is getting hot or warm. They can give off a funny smell as well.
It's a good learning tool, but unfortunately it's not worth the money and effort you're putting into it.
Reply With Quote
  #25  
Old 08-10-2018, 10:14 PM
Sealtest Sealtest is offline
VideoKarma Member
 
Join Date: Dec 2017
Location: Knoxville, Tennessee
Posts: 129
Quote:
Originally Posted by dieseljeep View Post
Feel the electrolytics and see if the main one is getting hot or warm. They can give off a funny smell as well.
It's a good learning tool, but unfortunately it's not worth the money and effort you're putting into it.

Haven't felt the cap for heat yet, but I can smell something strong when the set is on. Kinda like a mix of burning rubber and warm electronics smell, but it fills the room kinda fast.

Yeah I have to agree. TVs are good to learn on but make no money. But if I was into it for the money I wouldn't be doing it. Personally I just really hate flat screen TVs and want these CRT sets to stick around in general circulation as long as possible.
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 04:43 PM.



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