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Sooo I'm fixing my TV...

permanewb

Jan 11, 2014
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It's a Mitsubishi rear projection TV, model VS-60803. As it seems to be with everyone else on the internet who owns this TV, the convergence ICs went out. After installing some new OEM ICs the blue channel converged but red did not.

Anyways, to the point. The parts in the picture below turned out to be dead (no continuity) so I pulled them from the board. Google says the first two (which are the same) are fast recovery diodes. I haven't had any luck figuring out what the other four are (the last two are the same). It would be great if someone could help me identify these. The text to the left of the parts is how they are identified on the board (I've had no luck on Mitsubishi's website and haven't been able to put my thumb on a schematic for this particular model) and the text on the right is what appears on the part (the last two don't have any text).

Obviously I only know enough about this kind of stuff to be dangerous with a soldering iron. But I want to learn! So please, if you identify any of these parts, let me know how you did it.

Cheers
 

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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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When I read "mitsubishi" I thought car, and then I read "rear projection" and thought Gee, the back of your car must be huge to be able to project a TV image into it!

At this point I realised I needed to start reading again from the beginning!

Welcome to Electronics Point permenewb!

The first thing I can say is that I'm not certain that the bottom two diodes are the same. They might look the same, but without a schematic (preferably with a parts list) it's not easy to be sure.

The next thing it that although diodes can fail open circuit, it's far more likely that (without obvious physical damage) that they fail short circuit. These are diodes and they will read open in one direction.

Having said that, I'd probably just try a 1N4148 for the bottom two and hope that these are not zener diodes or something exotic.

But in general, I'm confused about what you've written to the left and right of the diodes. What is this? Is it what's written on the board, or on the component, or something else?

I'm sure that some of those larger devices have part numbers (at least partial part numbers) printed on them. Have you noted what they are?
 

permanewb

Jan 11, 2014
3
Joined
Jan 11, 2014
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When I read "mitsubishi" I thought car, and then I read "rear projection" and thought Gee, the back of your car must be huge to be able to project a TV image into it!

At this point I realised I needed to start reading again from the beginning!

Welcome to Electronics Point permenewb!

The first thing I can say is that I'm not certain that the bottom two diodes are the same. They might look the same, but without a schematic (preferably with a parts list) it's not easy to be sure.

The next thing it that although diodes can fail open circuit, it's far more likely that (without obvious physical damage) that they fail short circuit. These are diodes and they will read open in one direction.

Having said that, I'd probably just try a 1N4148 for the bottom two and hope that these are not zener diodes or something exotic.

But in general, I'm confused about what you've written to the left and right of the diodes. What is this? Is it what's written on the board, or on the component, or something else?

I'm sure that some of those larger devices have part numbers (at least partial part numbers) printed on them. Have you noted what they are?

Thanks for the welcome steve! The car projection thing could make for an interesting project.

So the bottom two are diodes? Judging by the Wikipedia article and an image search I would say you hit the nail right on the head with 1N4148.

I knew that some components read open in only one direction so I tested both directions to be sure (embracing my newbness).

In the picture, the stuff written to the left of the parts is what was printed on the board next to each part. I presume this is some kind of part number that can be used in conjunction with a parts list/schematic (which I still haven't been able to track down). The stuff written to the right of the parts is what was actually printed on each part.

I have discovered that VS-50800 is the base model for VS-60803, so they should have the same service manual and very similar schematics.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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I think they're probably all diodes. The fact that they have a "D" designation is highly suggestive.

Those bottom 2 diodes could be all manner of things (there are bazzilions of diodes that look like that). However, if one is going to guess at such a diode, 1N4148 or 1N914 are typically what you'd go for.

Try to find a service manual. Take a look in the following thread for some suggestions on how to do that.

https://www.electronicspoint.com/but-before-you-ask-work-progress-t228862.html
 

permanewb

Jan 11, 2014
3
Joined
Jan 11, 2014
Messages
3
I think they're probably all diodes. The fact that they have a "D" designation is highly suggestive.

Those bottom 2 diodes could be all manner of things (there are bazzilions of diodes that look like that). However, if one is going to guess at such a diode, 1N4148 or 1N914 are typically what you'd go for.

Try to find a service manual. Take a look in the following thread for some suggestions on how to do that.

https://www.electronicspoint.com/but-before-you-ask-work-progress-t228862.html

Thanks for the link. I actually gave the Before You Ask thread a once over before starting my own. Still, no luck. I was able to find a schematic on http://www.eserviceinfo.com using the chassis number (VZ6), but none of the parts in question were in the convergence section.
 

DigiTech

Jan 29, 2014
1
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Jan 29, 2014
Messages
1
First off I just stumbled on to this forum, so take what I have to say for what it is worth. I'm an old retired engineer and don't work on TVs. But I have a friend that does and works for the company in question.
That said heres what he said dsd 95 likely a 1n5819 dsd96 the same dsd94 is a zener
d401 he has no idea this is not even on his schematics, and d932 and d940 are most likely 4148s.

he also said that so many variations exist that unless he has it in his hand he has no way to know and they could be anything.

ahh for the day of american made. it may have been junk but at least it was our junk, and you could find the part.

I wish you the best of luck! if I could see the board, it may have a sub # or ver # on it.
 
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