electronics, repairs, service manuals and datasheets discussion community for the repairs professionals and technicians
FAQSearchMembersGroupsRegisterProfilePM'sLogin/Out
Rolling Screen on Mitsubishi Rear Projection TV – Model VS-5

 
Post new topic   Reply to topic    Electronic equipment repair and service manual search discussion Forum Index -> Equipment Repairs
View previous topic :: View next topic  
Author Message
joshua4891
Guest





PostPosted: Sun May 20, 2007 3:52 am    Post subject: Rolling Screen on Mitsubishi Rear Projection TV – Model VS-5 Reply with quote

Rolling Screen on Mitsubishi Rear Projection TV – Model VS-5071

Mitsubishi Rear Projection TV
Model: VS-5071
Manufactured: March 1994


I am having a problem with a fast rolling screen on the above tv. I’ve tried to make as many observations as possible to be helpful.

Observations: Done while synced up with working tv for comparison, so I could tell what the scene really was. Tried all following observations on component and coaxial inputs.

With screen of white snow:

-The snow looks fine, no funny colors or blotches.
-The green on screen text is stable, no jumps, rolling, or double images.

On Black Screen:

-The Green Text jumps slightly and has a shadow/double of red text offset about ¾” to the left.
-Text does not roll.

Color Movie Screen (dvd):

-Screen roll (seems bottom to top) rapidly.
-Text is the same as on the black screen.
-When playing a scene with black background and white text, the white text seems to have a green tint to it, with a slight red shadow.

Watching TV:

-Imaged stabilized (stopped rolling) briefly when commercial had top Third white, middle third black with small red text, and bottom third white.
- Also stabilized when screen was black with white image (no color at all).
-Orange appears red and gray appears bluish (I think, image rolls so hard I’m not for absolute sure).
-Rolls on black screen with small white text (dish music channel)

VCR Color Movie:

-Always rolled on color screens. Even if paused, unless next situationà
-Stops rolling if tape is paused and has a lot of white static bands on it.
-Blue vcr screen (fill for no signal) appears correct color but has rolling shadow bands over it.

VCR Black and White Movie:

-Black and white film still rolls if playing, but if paused on certain scenes will stop rolling, still a little jumpy, but I think that is the vcr not the tv. Seems to be more likely to stop rolling on scenes with larger patches of white.
- Black and white movie when paused and stable has pink and lime green lines following the outlines of where some white and black meets.
-Pink and green lines appear on the screen at the same time, but do not appear on the same points. i.e. Where black and white meet will either be a pink or green line, but not both on the same boundary. Lines are about 1/8-1/4” wide, solid color, not striped, and up to 12” long.

That is all I have observed so far, that I know might be relevant. I can take pictures or maybe short video clips (don’t know how refresh rate will affect my camera) if that would be helpful. I appreciate any help anybody can provide.

Thank You,
Joshua
Back to top
minnie



Joined: 18 Aug 2005
Posts: 2880
Location: Hell

PostPosted: Sun May 20, 2007 4:31 am    Post subject: Reply with quote

Exact model??? Dry caps on the signal board. Model will help point me in correct direction.
Back to top
View user's profile Send private message Send e-mail
joshua4891
Guest





PostPosted: Sun May 20, 2007 10:41 pm    Post subject: Model #? Reply with quote

Hello Minnie,

Thank you for your reply. I looked all over the inside and out of the tv and couldn't find anywhere else that there was a more detailed (longer/different) model number than what I posted above. (VS-5071), but I wrote down a some more info I found while looking.

sticker 1 - on back:
------------------
Mitsubishi - Big Screen Television
Model: VS-5071
AC 120V 50Hz 280W
Serial- 007322

-------------------------
===========
-------------------------

Sticker 2 - on back
------------------------
Mitsubishi Electric Corporation Manufactured:
March 1994 M1LA

-----------------------
=========
----------------------

Sticker 3 - Inside, behind speaker cover:
------------------
DWG: Q740B210-A1 Rev 00
1/12/94
HHD: 1038957
Label: 1044858
Serial: 06262

==========
+++++++
==========

I'm sorry if I am missing the correct numbers. If you happen to know where I should be looking, let me know and I'll look, maybe I'm just being blind today. Well anyways, I appreciate your response, and hope that I don't try your patience too much through this process.

Thank You Very Much,
Joshua
Back to top
eddwhatley



Joined: 03 Apr 2007
Posts: 5

PostPosted: Mon May 21, 2007 11:27 pm    Post subject: Reply with quote

Does the set have this pic in pic module...#930B552..if so suspect bad electrolytic capacitors on the module proper...the vert jits and sync is usually the first clues of worse things to ensue later as other caps degrade.

For a pictoral reference of the module...use this site for a pic of the module:
http://i4.ebayimg.com/04/i/05/68/c0/9e_1.JPG

Razz
Back to top
View user's profile Send private message
joshua4891
Guest





PostPosted: Wed May 23, 2007 6:31 am    Post subject: Found the PIP Reply with quote

Hello eddwhatley,

I found the PIP module finally. Pulled it out and between/around c7034, c7038, c7031, and the ic chip is several lines, and splatters of a black substance, can't tell for sure which cap it came from of probably more than one. Below is a link to a pic of the pip. Sorry it is broken up, the forum wouldn't let me post a working link since I'm not a registered member.


http://www.
freefileupload.
net/file.php?file=files/230507/1179899533/Pip.jpg
- Remove the retuns, enter the link, on the page that comes up, scroll down, and use the link "Click Here to download". Will be jpg format, about 185Kb.

If the pip is bad, which I now suspect it is, I'd rather just bypass it then repair it. I'm on satellite so in order to do use pip I'd need to pay for a second receiver, and I just don't think it would be worth it. I would, of course appreciate your opinion on how the thing looks, and what other tests to do, before I get overly excited that the pip is the problem, and I could actually be lucky enough for this to be a cheap fix.

Thanks for the help so far.

Joshua
Back to top
eddwhatley



Joined: 03 Apr 2007
Posts: 5

PostPosted: Wed May 23, 2007 8:05 pm    Post subject: Reply with quote

O. K. with your not particuarly having an URGENT need for that particular boards features, which BTW is a $250 ticket item and listed as no longer available from Mitsub supply. HOWEVER, using it or not, as you can see, CRITICAL sync, chroma and video signals are routed through the unit irregardless.
Your URL... WAS .. bumped with the critical preamble of the URL being omitted and only the tailing / sorting info being available.....sooooo...
I will just say that if this unit is personally yours and not being done for someone else, you need to be a world class solder-er with NASA /Mil spec quality of workmanship on some portions of that board...whilst using an iron tiplet of hypodermic needle sizing, as well as a stereo optical microscope being most helpfull in working in the micro flat pack IC's areas.
I am going to make it easy on myself with the supplification / utilization of photos for most of the info.
Yes, you did find electrolyte leakage on the board, as being the source of the black indelible stains that they left on the PCB proper. And somewhere I have a worksheet that I made up with the specific electrolytics at fault for specific "glitches" in gradual performance degradation. That stain produced, I have NEVER been able to get it completely of with an array of chemical cleaners, with acetone and MEK being at the top of the list as the most aggressive...but dont worry about it, as after you get it as clean as you can, it seems to be no problem.......But all of this is of no concern, as you will be pulling the board completely and installing the two bypasses of the sync /chroma/video aspects of the board. There are different schools of thought on the caps used, some say use non polorized electrolytics series connected -++- ( or two back to back conventional caps of twice the capacitance) to get the halved capacitance value in making them into a nonpolarized unit. Or another school says to just jumper the connections with no caps at all. And my personal preference was to use the non polarized cap for the sync aspect and a 1 ufd paper/ceramic cap for the video jumper. I will say that on some direct view...27-35 inch tube sets that there is a need to go down to the video detector circuit and adjust the video detector level pot in order to re-establish the proper bright-contrast inter relationship response, when bypassing the PIP unit. this may not be the case on your projo unit.

Refer to these pics:
http://members.aol.com/philselectronics/images/pip.gif
http://members.aol.com/philselectronics/images/pipby.jpg

Are we having fun yet ? Laughing

73's de Edd
Back to top
View user's profile Send private message
Guest






PostPosted: Wed May 23, 2007 9:02 pm    Post subject: Reply with quote

ADDENDA:
Finally, after toying with what info I could get and decryping your selected image host, I came up with this drawing. With the photo viewed, I then marked up with its pertinent info, although I'm sure that semitones of resolution inhibited me from seeing the progressively less intense areas of electrolyte damage to the PCB proper. Plus, under the large shield.... it is resplendent with those like caps. (With yet another micro sized flat pack with its large pinout.)

Direct technical info link:
Type in:
h t t p colon slant slant i m g 459 dot i m a g e s h a c k dot us slant
and then the balance afterwards, shown below, should cut and paste onto that preamble
img459/3553/deeeeeeeeeeefunkedpipbokb1.jpg

Mag it on up,for clarity...... its in J-peggggg.
73's de Edd
Back to top
joshua4891
Guest





PostPosted: Sat May 26, 2007 3:34 am    Post subject: Pip Bypass Success - 930B552 Reply with quote

Woo Hoo Very Happy, I have a working big screen. I took the capacitor values you recommended, and used the diagrams to bypass the pip. Took me about 15-25 minutes and viola, working tv. Adjust the convergence, reset the video settings, and clean the tubes/mirror/screen, and I get an almost perfect picture, the only tiny thing wrong now, is that when white text is on the screen, it has a very slight blue shadow, that is always on the side of the letter that is closest to the center of the screen. For instance, letters in the upper/right have blue shadows on the lower/left, letters in lower/left have shadow to upper/right, and centered letters have no shadow. But this effect is not noticeable while watching tv or movies so no big deal there.

And wow, $250 for this little circuit board Shocked, it is no wonder I could never afford a big screen. I know that previous sentence requires explanation. This is my very first big screen tv, it was given to my by some friends of mine, who have enough money that when the tv went bad, that just ran out and bought a new one, my line of thinking was, either I could fix it, or take it apart, either way would be fun. And so I have to thank you for enabling me to get my very first big screen tv, for $4.53. I am so glad I didn't have to repair the board, there would have been no way my soldering skill set would have been able to handle it. So should I hang on to this pip, trash it, or sell it? Even if I get a $100 out if it, when you are poor that is nothing to scoff at. I don't know, I'm just thrilled to have a big screen. Very Happy Very Happy Very Happy Thank You so Very Much for your help on this ! Exclamation !

Oh, and if anyone wants to download the picture of the pip board for future use in helping someone, feel free.

Thank You,
Joshua

a few key words to help others find this post:

Mitsubishi Rear Projection TV
Model: VS-5071 , VS5071 , 5071
March 1994
rolling screen, vertical hold, vertical sync, pip, picture in picture, bypass, pip-c, 930b552, roll, rolls, fix, replace, crt
Back to top
VenusButterfly12
Guest





PostPosted: Thu Dec 17, 2009 9:44 pm    Post subject: Mitsubishi CS-35401 - NO PICTURE Reply with quote

Can anyone post the instructions for the PIP bypass, please. I have someone who could probably fix my TV but we are not able to find the instructions ANYWHERE! I would be eternally grateful since tossing it would be a shame especially because it took THREE of us to get this monster to the second floor.

My email address is [email protected] if it's easier to email them.

Thank you in advance!
Back to top
minnie



Joined: 18 Aug 2005
Posts: 2880
Location: Hell

PostPosted: Fri Dec 18, 2009 12:23 am    Post subject: Re: Mitsubishi CS-35401 - NO PICTURE Reply with quote

VenusButterfly12 wrote:
Can anyone post the instructions for the PIP bypass, please. I have someone who could probably fix my TV but we are not able to find the instructions ANYWHERE! I would be eternally grateful since tossing it would be a shame especially because it took THREE of us to get this monster to the second floor.

My email address is [email protected] if it's easier to email them.

Thank you in advance!


http://sci.tech-archive.net/Archive/sci.electronics.repair/2004-11/2294.html

I don't use the caps unless you have no video when done.
Back to top
View user's profile Send private message Send e-mail
Display posts from previous:   
Post new topic   Reply to topic    Electronic equipment repair and service manual search discussion Forum Index -> Equipment Repairs All times are GMT
Page 1 of 1

 
Jump to:  
You can post new topics in this forum
You can reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


eServiceInfo on FB - Service Manuals Free Download - Service Diagrams

Free TV Schematics Download - HARDW.net - Pinout Master - Jabse Service Manual Search - Jabse.InK  - onTap.bg

SnimkiOt.com - Poblizo.com : пътешествия