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 06-10-2017, 08:16 AM
zeno zeno is offline
VideoKarma Member
 
Join Date: Mar 2013
Location: New Hampshire
Posts: 3,282
The AFC switches get noisy. So do the pots in the selector.
IIRC it has 2 tuners & a tuner control board. Check the board
for cold joints especially under the connectors. Some tuners
had connectors on them, same deal.
After that its an AFC problem which I doubt........

73 Zeno
LFOD !
Reply With Quote
  #17  
Old 06-10-2017, 07:16 PM
mr_fixer's Avatar
mr_fixer mr_fixer is online now
VideoKarma Member
 
Join Date: Jul 2007
Location: Tennessee USA
Posts: 568
Quote:
Originally Posted by jstout66 View Post
I was worried about that, and was watching this thread to see if a tuner issue cropped up. Those electronic tuners could be a pain in the ass, and were showing problems by the late 80's. It's Electronic, so there is no cleaning.
Start with the obvious... turn the AFC off, tune it in to the strongest signal/pix/ turn the AFC back ON. If it still has the problem, the tuner is a module, and you'll need to replace. If that's the case, let us know which one. It's listed on the schematic.
Ok this is what happened after i did that, I tuned in the pic with the afc off on ch 3, when i would turn on the afc switch , it would detune to a unviewable picture. When i tune in the tuner while the afc is on i get a regular pic for 10/20 mins or so.
as far as the tuner module number i could only find 2 numbers in reference to the tuner, first is 175-5074-01 plant 12 on a sticker on the tuner and 3439626 stamped in red ink on the tuner itself. The diagram on the inside of the cabinet only list the modules on the vertical chassis. I know it says on the module to not use contact cleaner on the tuner but what is the failure mode on these tuners, corosion? can they be repaired? I used to collect and repair watches as a hobby, i think i could dismantle the tuner if i knew what to look for.
Reply With Quote
  #18  
Old 06-10-2017, 10:48 PM
dishdude's Avatar
dishdude dishdude is offline
VideoKarma Member
 
Join Date: Feb 2014
Posts: 560
What happens if you just leave AFC off? If you're feeding it through a modulator on channel 3, AFC shouldn't be necessary anyway.
Reply With Quote
  #19  
Old 06-11-2017, 09:33 AM
zeno zeno is offline
VideoKarma Member
 
Join Date: Mar 2013
Location: New Hampshire
Posts: 3,282
By the book
Turn AFC off
Tune all channels for color pix without "worms"
Turn AFC back on. Should be good for years now.
Even with AFC off the set should work for years OK.

Selector module has only the following IIRC
AFC switch
Channel switch
18 tuning pots
AFC defeat switch ( defeats AFC during channel change )

Trouble shooting:
We did change some for erratic ops IIRC.
Try tuning ch3 on another slot (2 or 4)
Try tapping selector, VHF tuner, TNR control board &
150-190-01 IF module.
Defeat AFC by grounding the blue/white wire at tuner.
Monitor the tuning voltage at tuner. Dont remember color but its
NOT red, yellow or blue/white.
CHECK FOR COLD JOINTS !

CU later Zeno
LFOD !
Reply With Quote
  #20  
Old 06-11-2017, 07:45 PM
mr_fixer's Avatar
mr_fixer mr_fixer is online now
VideoKarma Member
 
Join Date: Jul 2007
Location: Tennessee USA
Posts: 568
well last night after trying the text book method that failed on channel 3, i switched the converter output and tv set to ch 4 and tuned in the set, it would detune a couple more times that evening, I fell asleep in my chair watching Svengoolie but as i awoke the next morning the set was still showing a great picture after being on all night. I think i will keep my eyes open for a 175-5074 tuner control "module and the tuner module "is this on the backside of the chassis or is it the long metal box or the left side of the chassis?" and have spares ready if i want to clean/repair these parts. Thanks everyone for their help and suggestions.
Attached Images
File Type: jpg DSC08916.jpg (68.1 KB, 49 views)
Reply With Quote
Audiokarma
  #21  
Old 06-12-2017, 06:32 AM
jstout66 jstout66 is offline
VideoKarma Member
 
Join Date: Aug 2003
Location: Ne
Posts: 1,483
It's the one that the tuning knob attaches to.
It's been years since I changed one, but it's basically "plug n play",
If it works on CH 4, and stays that way, I wouldn't worry, but if you come across a module I would snag for a spare. The tuner is totally electronic, so there is nothing to corrode. I can't remember what the specific part failed on them, but it was common. Doug Harland would be the one to explain how that works.
Reply With Quote
  #22  
Old 01-01-2019, 03:48 AM
mr_fixer's Avatar
mr_fixer mr_fixer is online now
VideoKarma Member
 
Join Date: Jul 2007
Location: Tennessee USA
Posts: 568
Hey everyone!, Sorry for resurrecting a long dead post but i have a new development: over the Holiday week i had a chance to install a new part. On ePay i found a new tuner control... module... selector whatever it is called. My set uses a 175-5074 module and i found a 175-5073 for cheap. The difference is the connectors and the angle of the base plate, It is used to connect it to the cabinet and tuner module which is a 175-2026 module. Well long story short, i found that the mechanical parts "variable resistor boards" are the same. this unit uses printed circuits on a ceramic substrate and are connected via a socket(s)????. I dismantled both units and swapped the new substrates for old and now the set has rock stable channels and has no de-tuning after a few days. Just thought i'd update my latest work with it's outcome. Logan
Reply With Quote
  #23  
Old 01-01-2019, 05:17 PM
zeno zeno is offline
VideoKarma Member
 
Join Date: Mar 2013
Location: New Hampshire
Posts: 3,282
Well done !
For future reference there are 2 major varactor tuner set-ups
in Zenith CC2 sets.
Early sets used separate UHF & VHF tuners ( 175- ### ) a tuner
control board ( 9-###) & a selector assy ( S-##### ).

Later sets used a big combo U/V tuner ( 175-#### ) & the
selector assy.

If you have more drift resolder the connectors on the big tuner
or if it has a control board on that. If that dont do it pull the tuner & look
for cold joints especially at the shield points.
BTW Selectors were known to drift but I dont know why. We just
swapped out the unit, it was faster & cheaper than troubleshooting
it.

73 Zeno
LFOD !
Reply With Quote
  #24  
Old 03-15-2019, 08:32 PM
Tim Tress Tim Tress is offline
VideoKarma Member
 
Join Date: Feb 2015
Location: Beaver Falls, Pennsylvania
Posts: 36
I was servicing those sets when they were relatively new. The 175-5074 and 175-5082 "tuner packages" were troublesome, and eventually Zenith started selling just the selector switch assembly as a replacement part.
Reply With Quote
  #25  
Old 03-16-2019, 01:42 PM
mr_fixer's Avatar
mr_fixer mr_fixer is online now
VideoKarma Member
 
Join Date: Jul 2007
Location: Tennessee USA
Posts: 568
Quote:
Originally Posted by Tim Tress View Post
I was servicing those sets when they were relatively new. The 175-5074 and 175-5082 "tuner packages" were troublesome, and eventually Zenith started selling just the selector switch assembly as a replacement part.
I don't suppose you might remember the zenith part number for the selector switch assembly? I'd like to find a few spares on ePay just in case.
Reply With Quote
Audiokarma
  #26  
Old 03-16-2019, 05:21 PM
Popester's Avatar
Popester Popester is offline
VideoKarma Member
 
Join Date: May 2012
Location: Lakewood, CO
Posts: 134
Also, those models had a neon lamp probably a NE-2 bulb illuminating the channel display. Set looks nice.
__________________
Sony Trinitron is my favorite brand.
My wish list:
Sony 8-301W
Sony KV-5000
Sony KV-7010U
Sony KV-1210U
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 10:08 PM.



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
ęCopyright 2012 VideoKarma.org, All rights reserved.