Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Jul Fri 25, 2014 9:06 am


All times are UTC [ DST ]



Post New Topic Post Reply  [ 9 posts ] 
Author Message
 Post subject: Zenith Chromacolor II Horizontal Shaking
PostPosted: Apr Thu 05, 2012 2:11 am 
Member

Joined: Dec Thu 08, 2011 4:03 am
Posts: 730
Location: Orland Park, IL
My chromacolor II television that I am in the process of repairing shakes fast in the horizontal direction every so often. The picture looks good when it is first turned on, but it starts shaking short and fast (it looks like the picture is vibrating) about once every 10 seconds. I tried the horizontal hold, but it didn't do any good. As I see the shaking, I hear a buzzing pitch from the main transformer change. Could this be a problem with the transformer? It gets hot after a while and constantly buzzes. Someone told me to change the oval shaped capacitor next to the transformer if it gets hot, but it does not get hot. It gets just a little warm after a while. Does anybody know what else could possibly be deteriorating?

Also look at my other forum for this TV. viewtopic.php?f=3&t=189977


Attachments:
2.JPG
2.JPG [ 85.88 KiB | Viewed 641 times ]
1.JPG
1.JPG [ 31.54 KiB | Viewed 641 times ]
Top
 Profile  
 
 Post subject: Re: Zenith Chromacolor II Horizontal Shaking
PostPosted: Apr Thu 05, 2012 2:20 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 12215
Location: Albuquerque, NM 87123
I would look for soldering problems with those upright connections, and try reseating the horizontal drive board.


Top
 Profile  
 
 Post subject: Re: Zenith Chromacolor II Horizontal Shaking
PostPosted: Apr Thu 05, 2012 3:03 am 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 20988
Location: Detroit, MI USA
Look for a 330Ω resistor on the horizontal module, they were known for going intermittent if this set uses that part.

_________________
Dennis

Experience is what you gain when the results aren't what you were expecting.


Top
 Profile  
 
 Post subject: Re: Zenith Chromacolor II Horizontal Shaking
PostPosted: Apr Thu 05, 2012 1:52 pm 
Member

Joined: Aug Thu 07, 2008 1:36 pm
Posts: 2256
Location: Orlando
so you can hear the PT buzz and that happens only when the pic shakes? are the intervals very regular?, the reason I ask is I had a printer that shared an outlet and it drove me crazy until I monitored my AC voltage at the outlet (I have a little box that plugs in and has a big expanded scale analog meter for line voltage) and noticed it would vary in regular intervals with the printer pluged in. I turned the print off and fixed the problem. Now with that constant voltage PT it would seem unlikely but may as well check. Before you use the TV anymore do you know if the saftey caps have been replaced on the HV side? I think I see white tube caps there, mine has a zenith "special" part number for those.


Top
 Profile  
 
 Post subject: Re: Zenith Chromacolor II Horizontal Shaking
PostPosted: Apr Fri 06, 2012 1:50 am 
Member

Joined: Dec Thu 08, 2011 4:03 am
Posts: 730
Location: Orland Park, IL
The transformer always buzzes. Not the high voltage unit. It is the black box all the way on the left. The buzzing changes pitches as the picture flutters, but not on regular intervals. It gets annoying because, sometimes it works well for a while and I think it is fixed, but then it starts shaking again. I tried unplugging everything in the room, but it didn't work. At this point, the picture was barely watchable, so I hooked up a different VCR. It helped with the shaking, but it didn't solve the problem. I know there is nothing wrong with either VCR because I checked them on a different TV. Also noticed that, on my newer VCR with a blue screen, I don't hear the buzzing pitch change from the transformer when I press stop (blue screen), indicating that it only happens when there is a picture. Same thing with a snowstorm static screen. Now I am thinking it is not related to the power supply. The problem might have to do with a loose tuning connection because of the television not being able to pick up a clear signal from the VCR. If I get the motivation to move the TV into another room with a cable box, I will try hooking it up without using a VCR.

As for the safety capacitors, they are the least of my concern. If the TV blows up for any reason, then it will end up on the curb! If I can't fix the horizontal shaking, it may end up on the curb anyway.


Top
 Profile  
 
 Post subject: Re: Zenith Chromacolor II Horizontal Shaking
PostPosted: Apr Fri 06, 2012 3:20 am 
Member

Joined: Aug Thu 07, 2008 1:36 pm
Posts: 2256
Location: Orlando
well if you give up on it, I will buy the chassis from you, as I have a 25CD56 and those are the best TV chassis ever built. If the CRT is good that is valuable as well, zenith CRT's are very good. If you want to try a horz board let me know the number I just picked up some spares recently.


Top
 Profile  
 
 Post subject: Re: Zenith Chromacolor II Horizontal Shaking
PostPosted: Apr Fri 06, 2012 8:20 pm 
Member

Joined: Mar Tue 03, 2009 11:12 pm
Posts: 503
Location: Hutchinson KS
I used to service those when they were new, and I think I remember there is a filter cap on the horizontal oscilator board that caused horizontal shaking. Also that resistor Mr. Detrola mentioned was a big troublemaker on several Zenith modual sets.


Top
 Profile  
 
 Post subject: Re: Zenith Chromacolor II Horizontal Shaking
PostPosted: Apr Fri 06, 2012 9:06 pm 
Member

Joined: Aug Thu 07, 2008 1:36 pm
Posts: 2256
Location: Orlando
I see a little 3uf 6v could that be it?


Top
 Profile  
 
 Post subject: Re: Zenith Chromacolor II Horizontal Shaking
PostPosted: Apr Sun 15, 2012 1:13 am 
Member

Joined: Aug Thu 07, 2008 1:36 pm
Posts: 2256
Location: Orlando
I tried using the OP horz board in my 25DC56, had it on for about 1 hr no shaking. There was a 5% 560 resistor that was about 710 so I replaced it, it was on the horz osc transistor. The 330 resistor looks to be a replacement, its a 1 watt WW looking job, checked right at 330 (mine is a carbon comp that was 370 but still works fine). I checked the 3uf value was good, could not check the leakage with my cap tester since it was a 6v and my lowest setting is 25v, but it seemed ok when tested with a diode test in the DMM. So the board seems ok, I will run it again for a while and see if it acts up. Need to OP to say how long it would take before shaking took place.


Top
 Profile  
 
Post New Topic Post Reply  [ 9 posts ]  Moderators: Mr. Detrola, 7jp4-guy

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 3 guests



Search for:
Jump to:  



















Privacy Policy :: Powered by phpBB