Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Play4aBuck
 
Posts: n/a
Default 27" Magnavox blacks out, also auto channel select fails.

Model Number: RS2749 602
Serial Number: 30271810
Pack Date: OCT, 1993
Chassis Model No: 27Z101-00AA

Problems: The picture will black out at random, but when working the picture
is good. TV powers up and works fine for several minutes to over an hour at
times. When it goes black, I can sometimes turn it off and back on to get
it to work, other times I have to let it rest, no patterns here. When the
picture is black, the sound can be heard but it is reduce by about 50%. If
left on long enough in the blacked out state, the picture did return once, I
found this out by accident when I failed to shut it off.

Also, the Auto Channel Programming feature fails to recognize which channels
are strong enough for viewing, thus sets all channels on. As it auto cycles
through the channels, it has a blue screen, but the left and right side is
blacked out, maybe about 2 inches on each side, looks like a inverted wide
screen. :-) I don't think it had the black edges before. Also, I can not
manual add/delete channels.

The Rest Of The Story:
The TV worked fine until I moved it from one cabinet to another, and left it
unplugged for days. After I plugged in back in, the programmed channels
were lost. I then found out the Auto Channel Programming Feature failed, so
I change the remote batteries, and it still didn't work. The manual channel
set fails to recognize the delete command. So I have to manually enter the
channel number or step through non-viewable channels to change the station.
After using the TV this way for maybe a day or two, the picture started to
black out.

I have the back off now. It's been unplugged for a couple of months.
Nothing smells burnt, nothing looks fried. I am assuming I can still get
shocked, so I am not touching anything.

After the visually inspection, I turn the set on and very carefully adjusted
the Screen and Focus controls, both work.

How long does it take this set to discharge?

Should I trash this? Did I maybe break a solder joint moving it? What do
you recommend?

Thanks for your time.

Cheers,
Jim




  #2   Report Post  
Jerry G.
 
Posts: n/a
Default 27" Magnavox blacks out, also auto channel select fails.

There is nothing you would be able to see visually unless there was a
catastrophic failure, and even then, not always. The fault may be in one of
the scan circuits or the power supply. The high voltage or the biases to
the CRT are being shut down, or going in to protection. Most likely in a set
of this age there would be a number of warn out capacitors in the various
areas.

You can call a reputable service rep for your set to give you an estimate.
From this you can make an intelligent decision about servicing it or not.
Considering that this is a very old set, it may not be wise to put too much
money in to it. This set will never perform as a new one, even if you put a
fair amount of service in to it. Also, if you invest any money in to it,
and if soon after there are more failures, the parts may not even be
available. You can easily end up spending too much on it in relation to
replacing it with something much better.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Play4aBuck" wrote in message
...
Model Number: RS2749 602
Serial Number: 30271810
Pack Date: OCT, 1993
Chassis Model No: 27Z101-00AA

Problems: The picture will black out at random, but when working the picture
is good. TV powers up and works fine for several minutes to over an hour at
times. When it goes black, I can sometimes turn it off and back on to get
it to work, other times I have to let it rest, no patterns here. When the
picture is black, the sound can be heard but it is reduce by about 50%. If
left on long enough in the blacked out state, the picture did return once, I
found this out by accident when I failed to shut it off.

Also, the Auto Channel Programming feature fails to recognize which channels
are strong enough for viewing, thus sets all channels on. As it auto cycles
through the channels, it has a blue screen, but the left and right side is
blacked out, maybe about 2 inches on each side, looks like a inverted wide
screen. :-) I don't think it had the black edges before. Also, I can not
manual add/delete channels.

The Rest Of The Story:
The TV worked fine until I moved it from one cabinet to another, and left it
unplugged for days. After I plugged in back in, the programmed channels
were lost. I then found out the Auto Channel Programming Feature failed, so
I change the remote batteries, and it still didn't work. The manual channel
set fails to recognize the delete command. So I have to manually enter the
channel number or step through non-viewable channels to change the station.
After using the TV this way for maybe a day or two, the picture started to
black out.

I have the back off now. It's been unplugged for a couple of months.
Nothing smells burnt, nothing looks fried. I am assuming I can still get
shocked, so I am not touching anything.

After the visually inspection, I turn the set on and very carefully adjusted
the Screen and Focus controls, both work.

How long does it take this set to discharge?

Should I trash this? Did I maybe break a solder joint moving it? What do
you recommend?

Thanks for your time.

Cheers,
Jim





  #3   Report Post  
James Sweet
 
Posts: n/a
Default 27" Magnavox blacks out, also auto channel select fails.


"Play4aBuck" wrote in message
...
Model Number: RS2749 602
Serial Number: 30271810
Pack Date: OCT, 1993
Chassis Model No: 27Z101-00AA

Problems: The picture will black out at random, but when working the

picture
is good. TV powers up and works fine for several minutes to over an hour

at
times. When it goes black, I can sometimes turn it off and back on to get
it to work, other times I have to let it rest, no patterns here. When the
picture is black, the sound can be heard but it is reduce by about 50%.

If
left on long enough in the blacked out state, the picture did return once,

I
found this out by accident when I failed to shut it off.

Also, the Auto Channel Programming feature fails to recognize which

channels
are strong enough for viewing, thus sets all channels on. As it auto

cycles
through the channels, it has a blue screen, but the left and right side is
blacked out, maybe about 2 inches on each side, looks like a inverted wide
screen. :-) I don't think it had the black edges before. Also, I can not
manual add/delete channels.

The Rest Of The Story:
The TV worked fine until I moved it from one cabinet to another, and left

it
unplugged for days. After I plugged in back in, the programmed channels
were lost. I then found out the Auto Channel Programming Feature failed,

so
I change the remote batteries, and it still didn't work. The manual

channel
set fails to recognize the delete command. So I have to manually enter

the
channel number or step through non-viewable channels to change the

station.
After using the TV this way for maybe a day or two, the picture started to
black out.

I have the back off now. It's been unplugged for a couple of months.
Nothing smells burnt, nothing looks fried. I am assuming I can still get
shocked, so I am not touching anything.

After the visually inspection, I turn the set on and very carefully

adjusted
the Screen and Focus controls, both work.

How long does it take this set to discharge?

Should I trash this? Did I maybe break a solder joint moving it? What do
you recommend?

Thanks for your time.

Cheers,
Jim


Probably just a solder joint, I'd focus around the power supply and flyback
transformer. I wouldn't worry much about getting shocked, most sets should
be fine to poke around in after a few hours, just avoid touching bare
connections that you don't know what they do.


  #4   Report Post  
Play4aBuck
 
Posts: n/a
Default 27" Magnavox blacks out, also auto channel select fails.

I want to thank both of you, Jerry and James for your replies.

I was hoping for a few more players to chime in, but I guess either this is
the same old story (problem) or maybe others have the same opinion, or don't
care to post.

My sister has the same set, and it's still going strong. My set still has a
good picture, until it blacks out, LOL!

I just hate the fact that it was working well, until I moved it and left it
unplug. This leads me to think that it's something physical
(cracked/loose). I've blown off the dust with an airgun and inspected every
solder point I could see, nothing obvious, I also pushed all the conectors
on tight.

I called one local shop and they said $35 to look at it, and if I decide to
fix it that goes toward the repair. I'm going to call another tomorrow. I
would not mind investing $50-75 but not much more, I've already replaced the
set. I'll let you know what was wrong with it....if I get it repaired.

Cheers,
Jim



  #5   Report Post  
James Sweet
 
Posts: n/a
Default 27" Magnavox blacks out, also auto channel select fails.


"Play4aBuck" wrote in message
...
I want to thank both of you, Jerry and James for your replies.

I was hoping for a few more players to chime in, but I guess either this

is
the same old story (problem) or maybe others have the same opinion, or

don't
care to post.

My sister has the same set, and it's still going strong. My set still has

a
good picture, until it blacks out, LOL!

I just hate the fact that it was working well, until I moved it and left

it
unplug. This leads me to think that it's something physical
(cracked/loose). I've blown off the dust with an airgun and inspected

every
solder point I could see, nothing obvious, I also pushed all the conectors
on tight.


Those are the best sort of problem though, they're the easiest to fix!


Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Auto Audio Channel Changer SeaAce Electronics 0 May 25th 04 08:29 PM


All times are GMT +1. The time now is 07:14 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright 2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"