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Discussion Starter #1
Does the fact that red is starting out so far out indicate a future problem with the circuitry? Why does red seem to be the most common to fail first?
So I never had a response to this, and now am at the point where that 'future problem' may be showing up..

Right now, the TV will *sometimes* fire up with the convergence way out of whack. Red seems to have a non-linear keystone stretch to the right, and blue the same but to the left.

Sometimes, it's not there. Sometimes, it goes away after a minute or two. Sometimes you can get it to go away by power-cycling the unit. Sometimes it won't go away at all.

Obviously, settings won't help as it reverts to perfect when the problem goes away. Any idea where to begin?
 

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Re: Step-by-Step for tuning convergence?

I just re-read your thread on convergence - http://www.hometheatershack.com/forums/diy-repair-maintenance/5600-crt-based-rptv-convergence-repairs.html

I'm not sure it would be an IC - one per channel, right? So two or more wouldn't be out then working perfectly again.

Broken resistor or solder joint would make sense but the problem exists cold or hot, can be cleared up by a power cycle at times. We've had some cool weather and it's gotten down to 60F in the room this TV resides in, yet the problem is still intermittent.

The issue *never* re-appears after it clears up, or if it doesn't happen in the first few seconds after power-up.

Thinking driver circuitry issue of some kind but really not sure where to begin..
..a
 

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Re: Step-by-Step for tuning convergence?

By far the most common problem with intermittent convergence on Mitsubishi sets are cracked solder joints on the ICs.

Post your model number and you may get more specific advice or information. For instance, some models use one IC for all channels, some use two 3 channel chips. Some have a tendency to have bad solder connections on the ICs, some do not.
 

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Re: Step-by-Step for tuning convergence?

It's the WS-65813 - V23

"This is the same basic circuitry used in the last few chassis types. There are only two major differences in V23 Convergence circuitry compared to that in the V21.
1) In the V23, the Waveform Generator is on the PCB-SIGNAL, not on a separate plug-in PCB.
2) Two Convergence Output ICs are used in the V23, only one was used in the V19."

So based on your tip, I took a look at the training manual, one IC handles Sub-V, the other Sub-H. As you can tell by the picture, it's only V that's the issue (right?) - so I should look for the Sub-V IC and check for cracked solder joints for that IC? "IC8CO 2"? I've looked at other areas of the circuitry (i.e. low pass filter and summing amp) and they don't share R & B signals, only the final output drive IC seems to.
..a
 

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Re: Step-by-Step for tuning convergence?

Leonard, can you split this thread at post 7 and title it "Intermittent convergence issue with 65813" ?
Thx,
..a
 

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Good suggestion. Keeping threads focused on one issue makes it much easier to follow and easier for others to find useful information.
 

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Re: Step-by-Step for tuning convergence?

It's the WS-65813 - V23

"This is the same basic circuitry used in the last few chassis types. There are only two major differences in V23 Convergence circuitry compared to that in the V21.
1) In the V23, the Waveform Generator is on the PCB-SIGNAL, not on a separate plug-in PCB.
2) Two Convergence Output ICs are used in the V23, only one was used in the V19."

So based on your tip, I took a look at the training manual, one IC handles Sub-V, the other Sub-H. As you can tell by the picture, it's only V that's the issue (right?) - so I should look for the Sub-V IC and check for cracked solder joints for that IC? "IC8CO 2"? I've looked at other areas of the circuitry (i.e. low pass filter and summing amp) and they don't share R & B signals, only the final output drive IC seems to.
..a
Yes, look to the output ICs for cracked joints or intermittent failures.
 

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Re: Step-by-Step for tuning convergence?

So we discovered that kicking the bottom of the chassis resolved the issue, and it didn't occur every time, so we lived with it until Thanksgiving, when I finally bought a flat-screen to replace it.

I hate to give up on it and throw it out, though, so I pulled it apart and took a good look at the solder joints on IC8C02. They look fine to my eyes, here's a hi-res pic of it (not embedded for the sake of those on low-speed connections!)

http://willetts.net/IC8C02.JPG

Do I need to remove the Power PCB and examine every connection? How the do you disconnect those micro connectors attaching it to the adjacent boards?
Thx!
..a
 

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There is a saying, "don't look for zebras when you hear hoofbeats."

Intermittent connections on the connectors between boards or on the output circuit are almost always the problem in these. Never saw one of those fail, certainly not intermittently.

Another common issue is a coolant leak, though I never saw manyu on that model. If there was ever coolant on the boards that is often a cause of bad connections but they can be very hard to find unless you trace signals with a scope.
 

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Discussion Starter #11
OK, so I don't see any cold/cracked solder joints on the board for IC800 & IC800. Should I just re-solder them and see if that fixes the issue?

TIntermittent connections on the connectors between boards or on the output circuit are almost always the problem in these. Never saw one of those fail, certainly not intermittently.
This seems to be a contradictory statement. You say those connections are almost always the problem, but that you never saw one fail. :dontknow:
 

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Those meaning the chip that you identified.

Sometimes the pins come loose where they are soldered into the chip. In that case just replace the chip. The only chips that are common failures are the output ICs. I have not bought any in a few years, and Sanyo has not made them for even longer than that, so I don't know what suppliers have reliable replacements or still have stock on the originals. You should research that or perhaps consult a local shop with experience with these sets. Don't believe everyone who says they have original Sanyo chips. Few actually do.
 

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Discussion Starter #13
I get it. They appear to be available for a reasonable price.

.. but how do I separate the PCB's? I can't figure out how to disconnect those white connectors with very closely spaced wires in a short ribbon cable. I don't want to force anything..
..a
 

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You have to carefully lift up on the small tab and apply a great deal of force without breaking the connector. It can be tricky. No way to describe it other than that. Pry hard, but be careful as they can break and then you have a bad problem. I never took the boards out unless they have coolant damage.
 
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