Mitsubishi CS-35301 Rolling Picture Problem?

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  #1  
Old 05-05-03, 06:45 AM
CCRT
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Mitsubishi CS-35301 Rolling Picture Problem?

I have a 9 year old Mitsubishi CS-35301 TV that recently started having reception problems on certain channels. The picture rolls and skips and double images appear on top of one another.

This happens when itís connected directly to the cable or though the supplied cable box. Iíve connected a smaller TV from another room and its picture quality is fine. This ruled out cable strength signal, I think?

I find it odd that the picture is perfect on some channel and not on others. Any help would be greatly appreciated.

David Maddalena
 
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  #2  
Old 05-05-03, 10:58 AM
Abbondanza23
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Rolling Image on CS-35301

I have had the same problem on my CS-35301 for 2 months now...I am looking into the possibility that there is a replacement chip for the verticle hold that can be replaced...or some other part solution?

anyone who has an idea on this I would appreciate your advice.

Also, the reason you have a stable picture at times is that the picture seems to stabilize when there is a mostly white image on the screen and rolls during darker images....
 
  #3  
Old 05-05-03, 11:03 AM
savedbythebell
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I have a cure for you. Contact me through our web site.
http://www.fixyourowntv.com

Dakota
 
  #4  
Old 05-05-03, 04:48 PM
Teratum
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About a month or 2, I posted several articles of how to diagnose and fix picture rolling of CS35301 in detail. At that time, my TV had the same problem so I fixed my own TV and helped other 2 persons fixed their CS35301/35305 which had the same picture rolling symptom.

I wonder if the modulator of this web site has the information still kept at the web that can be reprinted for others who have the same problem?

HopetoFixit was one of the 2 persons that I wrote to him in detail. Hopetofixit, if you still have the article that I wrote for you, can you please post it so CCRT and Abbondanza23 can use to fix their TV's?

If I still remember, the problem is not simply from the vertical IC. It's from the cap leak in PIP board and the analog switch (an IC) that process normal picture and the PIP pictures. Blindly replace the vertical IC will not fix the problem.
 
  #5  
Old 05-06-03, 04:24 AM
CCRT
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Thanks Teratum--

Since I don't use the pip feature, I'd be willing to bypass this completely if that would be an easier fix?

Do you agree that the the inconsistency from channel to channel is similar to problems youíve seen before?


Thanks for any help

David Maddalena
 
  #6  
Old 05-06-03, 09:34 AM
Teratum
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CCRT:

To bypass the PIP board is easy, but I have to go home to look up the schematic and the pin numbers.
I'll let you know tonight.

In the meantime, if you hook a known-good small TV through the Video out at the back of the CS35301, is the picture still rolling in the small TV? If the problem is in the PIP board or Analog switch as we suspect, the picture will not roll in the small TV, but continue to roll on the 35301.

Please try this simple diagnostic to close in on the problem.
 
  #7  
Old 05-06-03, 09:48 AM
CCRT
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Ok-- I'll give that "known-good small TV " test a try tonight.


Here's what I found so far fof bypass instructions.

"Try this: plug in a 4.7ufd @ 35v filter cap (+)at pin 5,(-)at pin 11. plug in a .01(any voltage) between pin 7 and 9. Just plug the caps into the socket, where the PIP board was mounted(they don't need to be soldered). Just don't let the leads from the two capacitors touch, as they cross each other. "


Is this the correct method? If so is than any polarity for the .01 cap between pin 7 an pin 9?

Why is the problem so inconsistency from channel to channel ? This is puzzling me.

Thanks and will be awaiting your reply
--Dave

http://home.earthlink.net/~ccrtracing/ccrt.htm
 
  #8  
Old 05-06-03, 05:27 PM
CCRT
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Update and Test results....

The "Small TV Test" works fine no v-hold problem.

The CS-35301 is now starting to have problems with almost every channel and VCR play backs.

I tried to use the PIP and the small picture is Black and White with the V-hold problem.

I took the back off tonight and located the PIP board. The # is 930B552 looks like rev 0

If I go with a bypass fix and remove the board entirely there is a brown wire soldered to one of the tin cases. What should I do with this once the board is removed? (ground wire?)

Is there any stored High Voltage area after the TV is unpluged that I should be aware of?

Thanks for any info, I look forward to your response

--Dave

BTW: I've snapped a few pics while back there, I'll be posting them shortly.
 
  #9  
Old 05-06-03, 06:02 PM
CCRT
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PIP Board
 
  #10  
Old 05-06-03, 10:54 PM
Teratum
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CCRT:

First of all the diagnostic with small TV works (with all channels) confirmed that the problem is likely after the IF detector and after the signal is fed into the output jacks at the back of the TV. The sync signals seem to be strong not to cause problem with any channel. So you know you have good signal up to here. This confirms you likely have problem at your PIP board or beyond.

"plug in a 4.7ufd @ 35v filter cap (+)at pin 5,(-)at pin 11. plug in a .01(any voltage) between pin 7 and 9.Just plug the caps into the socket,
where the PIP board was mounted(they don't need to be soldered). Just don't let the leads from the two capacitors touch, as they cross each other."
Per schematic diagram ,it is correct. The 0.01 cap is non-polarity, so either way it plugged is fine. Basically you will bypass y-signal through 4.7u, in pin 5, out pin 11, and bypass c-signal in pin 7, out pin 15 of the PIP socket.

But before you bypass the PIP board by removing it completely, try replace C7001 (4.7u, 35V) and C7002 (0.01u, 50V) in the PIP board. If you don't have surface mount capacitors, you can use electrolytic cap mounted it sideway and solder on to the PCB. You should have enough room to do so. Most likely it will fix the rolling problem. I have fixed my TV and Hopetofixit's TV this way. We did not do it by removing the PIP board completely.

But if you decide to remove the PIP board, you need to remove the brown wire from the PIP side and connect to the PIP socket either at pin 2, 4, 6, 8 or 10 which are grounds of the socket. The brown wire ground the tin can to prevent noise getting into whatever under the can. (If you do so and don't need the PIP board anymore, will you sell me your PIP board? I need a spare board to fix my other TV.) I think replacing leaky capacitor is a highly recommended method as to keep everything in its original shape. Otherwise you are making CS35301 to become CS20301 (no PIP) .

You also asked why the vertical hold is worse in some channels? I think it was because leaky C7001 or C7002 weaken the sync signal which become more obvious on channels with weaker signals. Therefore the picture did not hold. If you wait longer and the cap leakage become worse, you will soon have problem on all channels. Misubishi has a wierd way to use this sync signal to time the correct timing of the vertical sync pulse generated by IC201(M51414BSP). I'll not go into its theory of operation at this time, unless the 2 options above do not fix your problem then it might be something else deeper into the circuit.

Good luck and I sincerely hope it fixes your TV problem.

Teratum
 
  #11  
Old 05-06-03, 11:03 PM
Teratum
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Forgot to mention about the stray charges. Always unplug when you work inside the chasis since some part of the circuit are hot. If you leave the set unplugged for 5-10 minutes, it should be save to touch inside without being shocked.
 
  #12  
Old 05-07-03, 01:29 AM
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If I remember reading a bunch of posts in the newsgroups, that PIP board is plagued with leaking electrolytic caps. It's probably a good chance you probably have the same. To fix it, you'd almost have to swap out the majority of the caps on the boards to get it back in shape.

Any part with what looks like coke stains near the caps is suspect.

With that said, I wouldn't be surprised if the main signal/deflection boards have the same.

aaron
 
  #13  
Old 05-08-03, 07:05 AM
CCRT
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Teratum

Thanks for all the info.... I'll try it this weekend



Basically you will bypass y-signal through 4.7u, in pin 5, out pin 11, and bypass c-signal in pin 7, out pin 15 of the PIP socket.
Out pin 15????? Is this a typo?

I'll let you know about giving up the PIP board.

--Dave
 
  #14  
Old 05-08-03, 06:00 PM
Teratum
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Sorry, I made a typo. Old man's eyes not seeing so clear when I type. It should be out pin 9 (not pin 15).

Try to replace C7001 and C7002 first, so you may fix the problem without giving up the PIP board.
 
  #15  
Old 05-09-03, 04:26 AM
CCRT
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Success, Success, Success

Teratum-- Thank you very much for the great help and info

Success on the by-pass. Picture quality restored .


C7001 has visible (black) degradation on the trace toward the 1000uf cap

See photo below:



I'll be attempting the cap replacement on the board soon.

--Dave
http://home.earthlink.net/~ccrtracing/ccrt.htm
 

Last edited by CCRT; 05-09-03 at 12:12 PM.
  #16  
Old 05-09-03, 11:14 AM
Teratum
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Talking

Great news. I'm glad you have fixed it.
Be careful when you clean the PIP board. Whatever leaked out is corrosive.

Teratum
 
  #17  
Old 03-04-09, 02:19 AM
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Fixed it for me too!!!

Thanks to Teratum's bypass instructions, my Mitsubishi CS35301 is back in action!
 

Last edited by adamn; 03-04-09 at 02:57 AM. Reason: mentioned wrong name
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