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  
Don
 
Posts: n/a
Default Mitsubishi CS-3515R Television

I actually asked about this set quite some time back, but unfortunately have
lost me notes on the thread........

The set is a Mitsubishi CS-3515R (manufactured Oct 1992). When first turned
on, the picture is collapsed into a horizontal line midway between the top
and the bottom of the screen. Based on varying intensity and strong green
from the menu items (e.g. channel, volume, etc), it seems the horizontal
scan is fine. Sometimes after 5-30 minutes (i.e. the set "warms up") the
picture expands to full screen. Today when I was toying with it, the
picture would occasionally snap to full screen for less then a second and
then collapse into the horizontal line.

Given this the above, I am guessing:

1) A case of dried electrolytics in the vertical section.

2) Bad IC in vertical section.


Now for the questions:

1) Is this "collapsed" picture a relatively common problem?

2) If it is, any estimate on cost to repair?

3) Is it user serviceable (i.e. replace caps C101, C02, etc)?

4) Given the set is in otherwise very good condition, is it worth fixing?

Thanks!!

Don




  #2   Report Post  
Art
 
Posts: n/a
Default

Actually using an ESR meter you will find a fairly large number of caps that
may require replacing. The actual cost of those items are not all that much.
How was the picture quality before the vertical finally failed, if it was
good, indicating the CRT is probably in fair shape, it may be worth while
attempting the repairs. May want to acquire a Sams Photofact for the set, if
available, or a schematic, it will help you sort out what circuit you are
troubleshooting. Vertical Output should be a LA7837 or LA7838, a common
part. Also check for any supply resistors to the vertical circuit that may
have overheated or changed value.
"Don" wrote in message
k.net...
I actually asked about this set quite some time back, but unfortunately
have
lost me notes on the thread........

The set is a Mitsubishi CS-3515R (manufactured Oct 1992). When first
turned
on, the picture is collapsed into a horizontal line midway between the top
and the bottom of the screen. Based on varying intensity and strong green
from the menu items (e.g. channel, volume, etc), it seems the horizontal
scan is fine. Sometimes after 5-30 minutes (i.e. the set "warms up") the
picture expands to full screen. Today when I was toying with it, the
picture would occasionally snap to full screen for less then a second and
then collapse into the horizontal line.

Given this the above, I am guessing:

1) A case of dried electrolytics in the vertical section.

2) Bad IC in vertical section.


Now for the questions:

1) Is this "collapsed" picture a relatively common problem?

2) If it is, any estimate on cost to repair?

3) Is it user serviceable (i.e. replace caps C101, C02, etc)?

4) Given the set is in otherwise very good condition, is it worth fixing?

Thanks!!

Don






  #3   Report Post  
Phil Bowser
 
Posts: n/a
Default

Given the fact that the set "sometimes" has a full picture, I believe
you need neither an IC or capacitors, although replacement of the
electrolytic capacitors around the vertical output would be good preventive
maintenance.

Sounds to me like the solder connections have cracked around the pins of
the vertical output IC (very common) and / or other components in that area.
As you so adequately put "toying with it" - you probably momentarily flexed
the circuit board or induced some physical impact that allowed the
connections to "make" and allow the set to develope a full picture for a
moment or so. If you're comfortable with a soldering iron, disconnect AC
power to it and have a good look at the pins of the IC with a magnifier, and
resolder as needed.


  #4   Report Post  
Don
 
Posts: n/a
Default

Art,

Sounds like not too bad of a weekend project!

Thanks!!

Don




"Art" wrote in message
...
Actually using an ESR meter you will find a fairly large number of caps

that
may require replacing. The actual cost of those items are not all that

much.
How was the picture quality before the vertical finally failed, if it was
good, indicating the CRT is probably in fair shape, it may be worth while
attempting the repairs. May want to acquire a Sams Photofact for the set,

if
available, or a schematic, it will help you sort out what circuit you are
troubleshooting. Vertical Output should be a LA7837 or LA7838, a common
part. Also check for any supply resistors to the vertical circuit that may
have overheated or changed value.
"Don" wrote in message
k.net...
I actually asked about this set quite some time back, but unfortunately
have
lost me notes on the thread........

The set is a Mitsubishi CS-3515R (manufactured Oct 1992). When first
turned
on, the picture is collapsed into a horizontal line midway between the

top
and the bottom of the screen. Based on varying intensity and strong

green
from the menu items (e.g. channel, volume, etc), it seems the horizontal
scan is fine. Sometimes after 5-30 minutes (i.e. the set "warms up")

the
picture expands to full screen. Today when I was toying with it, the
picture would occasionally snap to full screen for less then a second

and
then collapse into the horizontal line.

Given this the above, I am guessing:

1) A case of dried electrolytics in the vertical section.

2) Bad IC in vertical section.


Now for the questions:

1) Is this "collapsed" picture a relatively common problem?

2) If it is, any estimate on cost to repair?

3) Is it user serviceable (i.e. replace caps C101, C02, etc)?

4) Given the set is in otherwise very good condition, is it worth

fixing?

Thanks!!

Don








  #5   Report Post  
Don
 
Posts: n/a
Default

The picture was pretty good. That's why it seems such a shame to junk the
set if it is something relatively easy to fix.

Thanks again!

Don



"Art" wrote in message
...
Actually using an ESR meter you will find a fairly large number of caps

that
may require replacing. The actual cost of those items are not all that

much.
How was the picture quality before the vertical finally failed, if it was
good, indicating the CRT is probably in fair shape, it may be worth while
attempting the repairs. May want to acquire a Sams Photofact for the set,

if
available, or a schematic, it will help you sort out what circuit you are
troubleshooting. Vertical Output should be a LA7837 or LA7838, a common
part. Also check for any supply resistors to the vertical circuit that may
have overheated or changed value.
"Don" wrote in message
k.net...
I actually asked about this set quite some time back, but unfortunately
have
lost me notes on the thread........

The set is a Mitsubishi CS-3515R (manufactured Oct 1992). When first
turned
on, the picture is collapsed into a horizontal line midway between the

top
and the bottom of the screen. Based on varying intensity and strong

green
from the menu items (e.g. channel, volume, etc), it seems the horizontal
scan is fine. Sometimes after 5-30 minutes (i.e. the set "warms up")

the
picture expands to full screen. Today when I was toying with it, the
picture would occasionally snap to full screen for less then a second

and
then collapse into the horizontal line.

Given this the above, I am guessing:

1) A case of dried electrolytics in the vertical section.

2) Bad IC in vertical section.


Now for the questions:

1) Is this "collapsed" picture a relatively common problem?

2) If it is, any estimate on cost to repair?

3) Is it user serviceable (i.e. replace caps C101, C02, etc)?

4) Given the set is in otherwise very good condition, is it worth

fixing?

Thanks!!

Don










  #6   Report Post  
Don
 
Posts: n/a
Default


Phil,

Maybe a poor choice of words in using "toying". Didn't actually have the
set apart (or whacking it with a 2x4! More case of channel changing and
video source changing.

Between your response and Art's, I might take a peek inside. I'm more of a
digital type, but certainly know how to read a schematic, trace circuits,
and which end of the soldering iron to hold!

Thanks!


Don




"Phil Bowser" wrote in message
...
Given the fact that the set "sometimes" has a full picture, I believe
you need neither an IC or capacitors, although replacement of the
electrolytic capacitors around the vertical output would be good

preventive
maintenance.

Sounds to me like the solder connections have cracked around the pins

of
the vertical output IC (very common) and / or other components in that

area.
As you so adequately put "toying with it" - you probably momentarily

flexed
the circuit board or induced some physical impact that allowed the
connections to "make" and allow the set to develope a full picture for a
moment or so. If you're comfortable with a soldering iron, disconnect AC
power to it and have a good look at the pins of the IC with a magnifier,

and
resolder as needed.




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
ICs for Sale - Specials, obsolete and Memory The Photographer Electronics Repair 0 June 3rd 04 11:40 PM
ICs for Sale - Specials, obsolete and Memory Kristy Electronics Repair 2 April 14th 04 04:24 AM
ATT; Hobbyists and Repairmen I have accumulated a room of ICS, Transistors, Diodes , Mem Chips , Proms etc Kristy Electronics Repair 1 December 8th 03 04:06 AM
Help needed to Akai television kica Electronics Repair 2 October 19th 03 04:42 PM
how to tune old Magnavox Television Vatsan Electronics Repair 2 August 4th 03 06:50 PM


All times are GMT +1. The time now is 05:56 AM.

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"