What do you do when...

Serendipity

madmax wrote: »

No chance it could be an input setup issue?
madmax

That's what I thought it was at first, since projectors usually require calibration. However, it appears that something is shorted within the unit, because even basic controls (such as brightness) can be adjusted from 0 to 100 with no effect on the image.

treitz3

Max, a further discussion was made here....

http://www.polkaudio.com/forums/showthread.php?t=61592

Serendipity

treitz3 wrote: »

Max, a further discussion was made here....

http://www.polkaudio.com/forums/showthread.php?t=61592

Yes, however, it appears that something is still shorted within the unit.

treitz3

Are you able to locate the short to a particular board / area?

Serendipity

treitz3 wrote: »

Are you able to locate the short to a particular board / area?

Maybe, but I'm just doubtful of my own skills because I'm still a student...

Serendipity

It looks like I have it narrowed down to somewhere between where the G2 voltages are generated (high voltage section, like in a TV set) to the control circuitry on the input board.

madmax

I did a search for repair manuals, SAMS notes etc for that model and didn't net anything. I wonder if guys at some of the better video forums might come up with some troubleshooting info? It has to be out there somewhere.

Serendipity

I'm trying to think simple here -

The G2 voltages exist because the tubes are lit up. However, one tube is overdriven. Kind of like a rear projection set in which there is massive red push except in my case it's excessive green. So there is something wrong there.

The other thing I am thinking is that the control circuitry *tries* to do something - ramping a control from 0 to 100 results in the numbers changing and I can see that the projector is trying to adjust. However, all I get is a slight flicker in between each step of the brightness control. So to some extent, the circuitry *is* working, just not doing what it is supposed to do.

Serendipity

It appears there is something wrong on the board in the attached picture, where the BKGOUT, DRV, and BRT circuitry is, labeled on the board. However, I have no idea how to go about replacing the components, as they are TINY!

treitz3

I can't see anything in the pic [too small]. Are the Ic's getting the 12v's? Pin neg.'s still below .04v's?

Serendipity

treitz3 wrote: »

I can't see anything in the pic [too small]. Are the Ic's getting the 12v's? Pin neg.'s still below .04v's?

Is this any better?

treitz3

Little bit. I take it that you do not have the schematics?

Serendipity

treitz3 wrote: »

Little bit. I take it that you do not have the schematics?

No, but I can order a service manual from Sony. Give me a sec. and I'll pull out the other board that I re-capped, just to make sure that I did it correctly.

treitz3

I would suggest that. You are shooting in the dark until then. Hopefully they won't charge you $150.00 to order them. They might also have them online for TV repair shops. Might want to ask your teacher if he knows any way to access them. I believe you need a password to get Sony's schem's, but it's been a while since I have been in the industry and I don't know what has changed.

Without the schem's, you are just shooting in the dark. You need to able to calculate the voltages across and between certain boards in order to isolate the origin of the component(s) in question.

Serendipity

Another possibility is that something worked its way loose in the projector since there are many places for things to fall out easily:

Serendipity

treitz3 wrote: »

I would suggest that. You are shooting in the dark until then. Hopefully they won't charge you $150.00 to order them. They might also have them online for TV repair shops. Might want to ask your teacher if he knows any way to access them. I believe you need a password to get Sony's schem's, but it's been a while since I have been in the industry and I don't know what has changed.

Without the schem's, you are just shooting in the dark. You need to able to calculate the voltages across and between certain boards in order to isolate the origin of the component(s) in question.

I will get the schematics.

treitz3

Sorry, I'm cooking in between posts. On post #42. Can you check to see if the input voltage is OK there? Ground still good? That might help to determine whether or not it is the smaller board or not. I'd be more concerned with DC at this point.

Serendipity

Unfortunately I'm not at school right now, so I don't have access to a DMM or any test equipment for that matter. The good thing is, I did get the service manual.

treitz3

For Ic's and DC, a DMM would be fine. For A/C lines w/ a DC pulse, yea, you'll need a sillyscope. If you are going to get into electronics, getting a basic DVM/DMM will not be a purchase you will ever regret for home use. I use mine all the time for a multitude of reasons.

I think I got my Fluke DMM for 150....give or take. Of course this was a while back, but I have seen prices go consistently down since I purchased mine. Food for thought.

Serendipity

treitz3,

You have an email

Serendipity

So - I got a service manual, but it is very confusing to understand. Very different departure from the schematics we work with in electrical engineering class...we note everything in class, yet it seems like the guys at Sony got lazy

Serendipity

treitz3 wrote: »

For Ic's and DC, a DMM would be fine. For A/C lines w/ a DC pulse, yea, you'll need a sillyscope. If you are going to get into electronics, getting a basic DVM/DMM will not be a purchase you will ever regret for home use. I use mine all the time for a multitude of reasons.

I think I got my Fluke DMM for 150....give or take. Of course this was a while back, but I have seen prices go consistently down since I purchased mine. Food for thought.

I think I will go and get a DMM for personal use.

How about something like this? http://www.radioshack.com/product/index.jsp?productId=2104750&cp=2032058.2032235.2032305&pg=1&searchSort=TRUE&y=11&retainProdsInSession=1&x=13&s=D-StorePrice-RSK&parentPage=family

treitz3

I would stay away from Rat Shack DMM's. I had one that lasted 10 minutes before it blew up and I was only checking a low level DC. It has also been reported to me that they have other issues as well, with virtually no protection circuits within. Pieces of crap if you ask me.

Look up item #330204202986 on E-bay. This is right up your alley

Serendipity

treitz3 wrote: »

I would stay away from Rat Shack DMM's. I had one that lasted 10 minutes before it blew up and I was only checking a low level DC. It has also been reported to me that they have other issues as well, with virtually no protection circuits within. Pieces of crap if you ask me.

Look up item #330204202986 on E-bay. This is right up your alley

I will look at a Fluke or something equivalent.

In the meantime, to rewind this thread a page and a half, I'd like to give everyone a "buyer beware" warning when shopping online, eBay, audiogon, etc. since anyone can get scammed easily these days and you must be careful when buying used. Trust the voice of experience, one can easily lose thousands of $$$, as I did.

Serendipity

This F'n sucks.

That is all I have to say.

BaggedLancer

Suggestion, quit fooling around with the board, don't solder or unsolder anything.....buy the replacement board for $1500, get it working and be done with it as a lesson learned. You spend $150-$500 on testing equipment and you are already at 1/3 of the repair cost.

I have no idea what you paid for it but I'm guessing a couple thousand atleast.....no sense in that going down the drain if you try to solder and unsolder things yourself and end up making it worse.

Grab an extra job for a couple weeks, make the $1500 and pay for the repair and be done with it. IMHO, that's the only way to go with a piece of electronics like that and the little experience that you say you have.

Serendipity

BaggedLancer wrote: »

Suggestion, quit fooling around with the board, don't solder or unsolder anything.....buy the replacement board for $1500, get it working and be done with it as a lesson learned. You spend $150-$500 on testing equipment and you are already at 1/3 of the repair cost.

I have no idea what you paid for it but I'm guessing a couple thousand atleast.....no sense in that going down the drain if you try to solder and unsolder things yourself and end up making it worse.

Grab an extra job for a couple weeks, make the $1500 and pay for the repair and be done with it. IMHO, that's the only way to go with a piece of electronics like that and the little experience that you say you have.

But I'm already getting there! If you read the thread http://www.polkaudio.com/forums/showthread.php?t=61592 you can see that I replaced some capacitors in the high voltage section and the problem improved, now there are still other things wrong with the unit.

treitz3

This will be a great learning experience as his knowledge of electronics expands, not to mention a challenge that he can achieve. My .02 cents......

Serendipity

I love challenges!

On another note, I am still pissed about the whole deal on the 'gon. Oh well...

sucks2beme

Go check CL for a meter and /or a scope. A pawn shop is a good place to get a Fluke for less.A cheap o-scope would tell you a lot more on what's going on. If you're gonna work in the industry, just as well get a few things to start off.

Note: as an engineering student, you have now learned the importance of good documentation as a troubleshooting aid. You now know why a lot of techs go crazy with this stuff. Poor schematics, test points with no reference values listed, and best of all, custom chips that can't be bought in less than quantities of a 100. Good luck!