Videokarma.org

Go Back   Videokarma.org TV - Video - Vintage Television & Radio Forums > Rectangular Screen Tube Televisions

We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #1  
Old 03-22-2010, 02:08 PM
Adam's Avatar
Adam Adam is online now
VideoKarma Member
 
Join Date: Oct 2005
Location: Madison, WI
Posts: 2,175
1974 Zenith Avanti (25EC58)

This is one of 2 sets I picked up from drh4683 yesterday, it uses the very last of the horizontal solid state chassis, and the SC600 remote. Initially turning it on only revealed 2 minor problems, a dirty vol control and a problem with the channel number lights staying lit. The picture on this set is excellent, the remote unit works consistently, but after watching it for a while last night, I had more trouble with the sound. Sometimes the sound will just cut out entirely, when this happens I can still hear static when I turn the volume control, so the audio output is still working. Turning the set on and off a few times always restores the sound. This uses the 150-214 sound module, which has no transistors, just 2 ICs. Once I fix the sound, this set will probably replace my ctc-10 as my main watching set.

The other set I picked up is this 63 Zenith 19" b/w SC300 in the metal cabinet. The set itself needs some cleaning up, but works fine, although the remote receiver isn't working at all. If anyone has any of the built in antennas that go with these, I now have 3 sets that need them. I also need to come up with something to replace the missing 4 plastic pads on the bottom of this set. I think I could never collect too many Zenith b/w sets in metal cabinets, this is my 5th.
Attached Images
File Type: jpg 74zenith.jpg (100.2 KB, 208 views)
File Type: jpg 63zenith.jpg (86.1 KB, 193 views)

Last edited by Adam; 03-22-2010 at 02:28 PM.
Reply With Quote
  #2  
Old 03-22-2010, 02:29 PM
zenithfan1's Avatar
zenithfan1 zenithfan1 is offline
Mark
 
Join Date: Jan 2008
Location: Kenosha, Wisconsin
Posts: 4,136
Very nice!
__________________
My TV page and YouTube channel
Kyocera R-661, Yamaha RX-V2200
National Panasonic SA-5800
Sansui 1000a, 1000, SAX-200, 5050, 9090DB, 881, SR-636, SC-3000, AT-20
Pioneer SX-939, ER-420, SM-B201
Motorola SK77W-2Z tube console
McIntosh MC2205, C26
Reply With Quote
  #3  
Old 03-22-2010, 02:45 PM
radiotvnut's Avatar
radiotvnut radiotvnut is offline
VideoKarma Member
 
Join Date: Jul 2007
Location: Meridian, MS
Posts: 5,888
Those are a couple of winners for sure! I too like those old metal cabinet Zenith sets.
Reply With Quote
  #4  
Old 03-22-2010, 07:24 PM
Adam's Avatar
Adam Adam is online now
VideoKarma Member
 
Join Date: Oct 2005
Location: Madison, WI
Posts: 2,175
Concerning my sound trouble, I want to try swapping out that 1st IC which, I think?, corresponds to the sound IF amp through detector circuits in a regular tube tv. The Zenith part # is 221-481. 221-48 = nte-1162, while 221-48-01 = nte-712. But I can't find a cross-reference with just 221-481, is the part I need one of the above 2, or something else? Working on such a "late-model" tv is unfamiliar territory for me.
Reply With Quote
  #5  
Old 03-22-2010, 07:33 PM
zenithfan1's Avatar
zenithfan1 zenithfan1 is offline
Mark
 
Join Date: Jan 2008
Location: Kenosha, Wisconsin
Posts: 4,136
Is the space command chassis similar to the older versions with rotary step switches? If so, did you clean them too? I too am unfamiliar with these, I know, WTF? with my name being "zenithfan1" I should already know Like I've said beore, Space Command sets elude me for some reason. I only have a few around here and never one that new. I hope you get it working, that's a great daily watcher and will most likely outlast you.
__________________
My TV page and YouTube channel
Kyocera R-661, Yamaha RX-V2200
National Panasonic SA-5800
Sansui 1000a, 1000, SAX-200, 5050, 9090DB, 881, SR-636, SC-3000, AT-20
Pioneer SX-939, ER-420, SM-B201
Motorola SK77W-2Z tube console
McIntosh MC2205, C26
Reply With Quote
Audiokarma
  #6  
Old 03-22-2010, 07:43 PM
Adam's Avatar
Adam Adam is online now
VideoKarma Member
 
Join Date: Oct 2005
Location: Madison, WI
Posts: 2,175
This is an unusual model in that it has the newer motorized veractor tuner like in the later vertical chassis sets, but still uses the older horizontal chassis. It's even called a chromacolor II, which I thought referred specifically to the vertical chassis, but it seems Zenith started using cc2 in 74 for both kinds of sets.

Whatever is wrong with the sound does not affect the picture at all, and changing the channel or adjusting the tuning has no effect on the sound when it goes out at all, so I'm fairly certain the problem is limited to that sound module. I watched it for several hours today, about once an hour the sound would cut off, turning the set off and on again always brings it back (sometimes I have to do it 2 or 3 times)
Attached Images
File Type: jpg DSCF1996.jpg (118.3 KB, 95 views)

Last edited by Adam; 03-22-2010 at 07:50 PM.
Reply With Quote
  #7  
Old 03-22-2010, 08:34 PM
Jeffhs's Avatar
Jeffhs Jeffhs is offline
<----Zenith C845
 
Join Date: Feb 2003
Location: Fairport Harbor, Ohio (near Lake Erie)
Posts: 3,537
If the sound goes off every hour, and turning the set on and off always brings it back, my best guess would have to be that there is an intermittent that only acts up after the set has been playing awhile. However, this is only a guess, and since you can always get the sound to come on again by rapidly switching the power on and off, it probably isn't a very good guess at that. I'd check the sound module for cold solder joints, cracks in the printed wiring board (this sounds like one of Zenith's modular chassis) and other things that would show up only after the set has been on and running for an appreciable length of time. This is called a "thermal" intermittent and can be the very dickens of a thing to find, but from your description (except for being able to get the sound back by switching the set on and off), it sounds like that may well be the cause of your sound trouble. You may be "shocking" a bad component or connection on the sound module into temporary normal operation by your rapid power switching, but the key word is "temporary" since the sound will disappear again in another hour.

Not being any kind of expert on Zenith TVs, especially the solid-state ones of the '70s through the nineties, however (most of my experience has been and is with older Zenith tube-type radios), I will step aside at this point and let the Zenith TV experts here like zenithfan1 and drh4683 guide you further.

Good luck. Those older Zenith TVs were great performers in their day, and can be again with proper servicing. I had a great-uncle who replaced the RCA color television chassis in a 3-way console in his living room with a 1974 19" Zenith Chromacolor II, IIRC; the set worked beautifully until he died in 1987. My great-aunt then got rid of the old console, bought a Zenith System 3 console and kept the latter from '87 until she died some 15 years later.

In its day (decades before Goldstar made a mockery of their name and reputation), Zenith was an excellent brand of TV; I had several of their black-and-white sets and a couple of their solid-state color portables, and had excellent results from all of them. The two Zenith color sets lasted 19 and 16 years, repectively, and were still working when I gave them up shortly before I moved to my apartment in 1999. I also had a 12" Zenith b&w solid-state portable that lasted 22 years and was still going strong when I got rid of it ten years ago. I would have kept it, goodness knows I should have, but my apartment was and is just too small for three TVs; I brought one Zenith color set with me when I moved here and bought a brand-new RCA CTC185 at almost the same time, so the li'l 12-incher had to go. I hated to part with that set and my two 13-inch portable color sets, but moving from a three-bedroom house with a basement to a one-bedroom apartment means lots of downsizing, as I'm sure many of you know.
__________________
Jeff, WB8NHV

Collecting, restoring and enjoying vintage Zenith radios since 2002

Zenith. Gone, but not forgotten.
Reply With Quote
  #8  
Old 03-23-2010, 09:47 AM
kx250rider's Avatar
kx250rider kx250rider is offline
REAL TVs have TUBES!
 
Join Date: Oct 2005
Location: Los Angeles & Dallas
Posts: 3,238
Adam, I have that sound module, if you need. I think the 25EC58 was the only set to use that module. I ordered a few extra new ones when my mother was using my Zenith in the 80s, and would blow up the audio module by having the volume out of control.

PM me if you want me to send you the module... I don't know if I can lay my hands on a new one at this point, as I have parts stashed everywhere and it's been 25 years since I ordered those new ones. I do have a few known, tested good ones.

Charles
__________________
Collecting & restoring TVs in Los Angeles since age 10
Reply With Quote
  #9  
Old 03-23-2010, 03:08 PM
Adam's Avatar
Adam Adam is online now
VideoKarma Member
 
Join Date: Oct 2005
Location: Madison, WI
Posts: 2,175
I think I found my sound problem. Look at this messy soldering on the bottom of the sound module. It looks like it cracked, and somebody tried to bridge the cracks, but didn't do it too good. It's not totally visible in the pic, but it's using this stranded wire which has loose strands touching other traces it shouldn't.

Charles, I'll send a pm about that module you have, thanks.

This is one of zeniths very first solid state chassis, so it's partially modular, and partially not. In some cases transistors plug into sockets on the chassis just like tubes would. It's an interesting chassis, I'll post some pictures of it later.
Attached Images
File Type: jpg Untitled.jpg (61.0 KB, 142 views)

Last edited by Adam; 03-23-2010 at 03:12 PM.
Reply With Quote
  #10  
Old 03-30-2010, 08:00 PM
Adam's Avatar
Adam Adam is online now
VideoKarma Member
 
Join Date: Oct 2005
Location: Madison, WI
Posts: 2,175
I did some work on the b/w set. The set worked fine except for the remote receiver unit, so on the tv chassis I just recapped the bumblebees, and kept the original electrolytic cans for now.

On the remote chassis, the selenium rectifier was open, and that 2 section 40mfd electrolytic was bad. I put a diode in, replaced all the electrolytics and the remote worked ... for just a few minutes ... Then the channel changer still worked, but the vol control didn't. First I swapped the 2 transistors that operated the channel changer and the volume control (X5 and X6), but the channel control still worked and the vol still didn't. Then I went and adjusted the alignment, which I was able to improve a little, but even though the unit appeared to be working and the alignment was good, it still wouldn't operate the volume switch.

The problem turned out to be mechanical, there is a crack in that plastic gear in which the spring which turns it forward gets stuck, and then doesn't allow the disc to turn (see 2nd pic). These plastic gears seem to be the one weak point in these Zeniths. The repairs I did to the plastic gears on the tuner motor on my Zenith color set with the SC400 are still holding, so I think this one should be ok too.

The only other problems with the set are the rubber belt for the fine tuning was broken, which I already replaced, and the channel indicator light is burned out.
Attached Images
File Type: jpg sc300.jpg (144.1 KB, 106 views)
File Type: jpg sc300b.jpg (80.8 KB, 103 views)
File Type: jpg 63zenith.jpg (79.4 KB, 100 views)

Last edited by Adam; 03-30-2010 at 10:24 PM.
Reply With Quote
Audiokarma
  #11  
Old 03-31-2010, 09:51 PM
drh4683's Avatar
drh4683 drh4683 is offline
VideoKarma Member
 
Join Date: Jan 2003
Location: Chicago, IL
Posts: 2,089
Looks nice. Glad you were able to get those going. Both those sets just sat in my storage unit and never got around to even taking the back off them. Nice to see them coming back to life and glad to see you used Sprague Atoms for the lytics! (made in USA and the best!). Watch out for that space command chassis though. That large heat shield for the transistors is asbestos.
__________________
I tolerate the present by living in the past...
To see drh4683's photo page, click here
To see drh4683's youtube page, click here
Reply With Quote
  #12  
Old 04-02-2010, 12:00 AM
Adam's Avatar
Adam Adam is online now
VideoKarma Member
 
Join Date: Oct 2005
Location: Madison, WI
Posts: 2,175
The 1963 b/w is now fully operational.
Attached Images
File Type: jpg 63zenith8.jpg (97.8 KB, 108 views)
File Type: jpg 63zenith9.jpg (145.7 KB, 123 views)
Reply With Quote
  #13  
Old 04-02-2010, 09:36 AM
sanjarali sanjarali is offline
Banned
 
Join Date: Apr 2010
Posts: 76
It is incredible to see that the television sets of remote control are existed in America in 1963! like wonderful that she has this television.
Reply With Quote
  #14  
Old 04-03-2010, 04:37 PM
Adam's Avatar
Adam Adam is online now
VideoKarma Member
 
Join Date: Oct 2005
Location: Madison, WI
Posts: 2,175
The first wireless remote control tv was the Zenith Flashmatic (which used a flashlight for a remote) back in 1956. Then Zenith began making the mechanical ultrasonic space-command remotes in 1957, RCA also came out with an electronic ultrasonic remote back in 1957. Way back in 1939-42 Philco even had a wireless remote control (an AM transmitter called the mystery control) in some of their console radios.

After watching the '63 for a while, it developed problems with both vert size and horizontal sync, but both are repaired now, and I also went and did a complete recap of the electrolytics this time.

I got a new sound module for the '74, swapped it in, and the sound works fine now. Now I just have to address the problem with the channel number lights being intermittent.
Reply With Quote
  #15  
Old 04-03-2010, 05:33 PM
sanjarali sanjarali is offline
Banned
 
Join Date: Apr 2010
Posts: 76
adam, thank you for giving me that the history of a remote control. It seems so very hard to believe that of things, tv existed so very long ago. In Oman, Télévision "only for the ruling class, or upper caste so we never saw such wonders, let'm alone a remote control.
Adam and thank you for giving me remote control after that date, it seems it is difficult to believe that these things have existed since the time of a very long. In Oman, but that the television the ruling class, or هذلك and so we have never witnessed such upper class wonders, let alone by remote control.

In my country I trained for military action electronics, but my family and left to the United States before the first of training. I still love Tinker with electronics.

I hope to learn more about this site.
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 10:00 PM.



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