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Hi steve, great thread. I've got the same model with the red convergence out and in the process of removing the circuit boards. How did you disconnect the 2 red high voltage wires from the back right of the convergence board ( I think it is G )?

The service manual says turn 90* counterclockwise, but no budge. Any ideas since I would like to remove the whole board from the set while soldering the new sdk390-570s. thanks.
 

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Discussion Starter · #22 ·
Sure, poke the bear! Ok, ok, you're probably wondering what that's all about . . . I just broke my Sony!!!

I've been really busy so I haven't had time to mess with this set. As I posted earlier it had an annoying small shadow, like a piece of lint, in the middle of the screen. Finally today I had a day off so I tore into it - I pulled the thing apart again and cleaned everything again. This time I even cleaned the mirror which looked clean when you shined a flashlight across it but left a suprising amount of grim on the microfiber cloth after I sprayed it with Sprayway cleaner. That did no good, it was still there (but the picture was brighter than before I cleaned the mirror so it did need cleaned). I even flipped the lenses 180 degress on the guns to see if it would change position - it didn't. GRRR! I moved the lenses to other guns and that didn't move it either. It simply had to be in the CRT, the lens pack, mirror, or screen. Probably not the CRT, the lens packs I moved around and it didn't move positions, and I cleaned the mirror to no avail.

Finally I decided to pull the screen and see if anything had gotten in between them. They were taped together but I cut the tape and proceeded to pull it apart. Well, it's wide and akward and there was a ceiling fan . . . yep! the lenticular lens is now missing a chunk!

Oh well, easy come easy go . . . it was annoying me anyway, I've just had this set apart too many times! I fixed myself a whiskey sour for now and towards the end of the week I'll pull the boards, hv block, focus block, etc. and stick 'em up on fleaBay - I'm sure someone will need some parts. All I really have in it is the cost of gas to go get it and the cost of the STKs so I should break even.

OK, back to your question . . . I didn't remove the focus block wire nor the hv block wire, I worked on the thing on the floor which sucked!!! If I ever work on another one of these I will pull the board all the way out. For the adventurous though, there is enough length on those leads to get the board a pretty good distance out. I just hate soldering while squatting on the floor, I'd rather be at my nice comfy bench.

I have repaired a 52" version of this set though and it had an hv block out so I had to remove the hv lead from the flyback. It was truly push in, twist 90 degrees, and out it came. I've read where it's easier to pull the wires at the focus block and hv block than it is to pull it from the flyback transformer so I think that's what I would try to do. Actually I will be doing that shortly when I scrap this set out - I'll sell the board with the two wires still attached.

I don't have the service manual handy, but I think the focus block wire just pushes in and out, I don't think it turns.

Read my other posts on the set with the hv block issue - Leonard kindly gave some words of wisdom at the end on how to get the hv lead out of the hv block.

Hope that helps, post back how it goes for you!

TTYL,

Steve
 

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Discussion Starter · #23 ·
Hi Nick,

OK, I'm working on salvaging the set today.

Yes, the small wire on the flyback that goes to the focus block just pulls straight off from the focus block no problem.

The other wire that goes to the hv block . . . just push in and hold it in while you peel the rubber boot back, then rotate 90 deg while you're pushing in and let up and it should come out. If not try again (it usually takes me a couple tries).

Here's some pics I took of the focus block, the wire that plugs into it, and the end of an hv wire - note the little wings on the end of the hv wire, those are very easy to break off if you just pull straight out so make sure you push in and rotate 90 degrees.

Hope this helps!!!

/Steve
 

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Discussion Starter · #24 ·
Working D board with STK 392-570s and focus & hv block leads still attached is up on fleaBay, item # is 180552905619

I thought I would salvage the boards, the hv block, focus block, and remote. If anyone needs anything else off of it speak up soon before the carcass goes to the landfill!

/Steve
 

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Discussion Starter · #25 ·
Well I tried to edit my earlier post and add this in but it wont let ya add an attachment when you edit, GRRR, I hate it when things don't work the same way every time!

Anyway, for those working with the HV wires and HV block here's a pic of the top of the HV block and the slots the little wings on the hv wire connector need to slid into. Note there are three slots - one at 9 o'clock, one at Noon, and one at 3 o'clock. The ones at 9 & 3 are the ones 180 degrees apart so they are the ones to use. When you reinstall the wires you'll find they naturally lay at 12 o'clock so you gotta rotate them 90 degrees, insert, and then release and they'll naturally rotate back to the position they should be in when properly inserted (hope that makes sense! This stuff is easier to do than describe!)

Take Care,

Steve
 

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Well, after reading more on removing the high voltage wire, I finally got 'em off. The board is now apart from the TV and waiting for the SDK's to arrive. STK 392-570s I tested the pico fuses under the headsinks, and they all read the same ohms, about 1.5. Does this sound correct? Sorry to hear what happened to your unit.
 

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Discussion Starter · #27 ·
Well, after reading more on removing the high voltage wire, I finally got 'em off. The board is now apart from the TV and waiting for the SDK's to arrive. STK 392-570s I tested the pico fuses under the headsinks, and they all read the same ohms, about 1.5. Does this sound correct? Sorry to hear what happened to your unit.
The picos should be a direct short - 0 ohms. If you're using an analog meter usually you can calibrate zero, just short the leads and turn the adjust knob. If you're using a digital meter they usually aren't calibratable (not in our price range anyway) and you're probably measuring the resistance in the leads - short them together and see what it reads, then remember to minus that off any readings you take.

Also, remember to check the picos on the G board that stands up vertical to the left of the D board you are working on - there's a couple on there that are commonly damaged too.

I'm not too upset over my unit - I'm in a unique situation as I didn't buy it new so I'm not nearly as invested in it as people who paid big bucks for their units are. I didn't really have a home for it either, I just ran across it so it's not like I got a hole in the living room where a TV needs to be! LOL! I got mine for a song and I actually kind of enjoy working on the things so I got my money out of it in entertainment value. If I get 'em running then great, if not oh well I'm not usually out much more than parts cost and some time and I put the parts up on fleaBay - I'm sure someone will need 'em eventually so in the end we'll probably still keep one out of the landfill a bit longer.

It sounds like you're on your way - remember to keep us posted on your progress!

Take Care,

Steve
 

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quick question, I also have a 48" JVC HDTV projection that had the convergence chips fixed and the tech also replaced a few blown resisters he told me. The set has been working on and off for the past 2 months.

There is a blue ghost when it goes out, but now it is working again. I've reseated everything, could it be anthing else i'm missing. Currently it is working perfect... keeping fingers crossed. lol.
 

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Discussion Starter · #29 ·
Hi Nick,

I think we're going to need a little more here as I know that at least my crystal ball isn't working right now!

What model of JVC is it?

What exactly is it doing? It sounds like there is a picture but a blue shadow appears? (i.e. the blue convergence is off)

Do you know where the tech got his STK chips?

I have an JVC AV56WP74 and I really like it. You wouldn't believe how bloody EASY it is to fix the convergence amps on it! I started a thread on my repair of that unit - it's at:

http://www.hometheatershack.com/forums/jvc/29648-steves-av56wp74-convergence-repair-pics.html

My guess would be a bad solder joint or poor quality STK chips that don't like it when they get hot. Since it's kind of an occasional problem I'm probably leaning towards a bad solder joint though you said you re-seated everything and now it's been have so maybe you got it.

Just my guess, but it sounds like the STKs aren't doing their job and it seems if you read this forums that convergence problems occuring after a repair usually result from poor quality STK chips, poor soldering, or loose wiring.

I've repaired two of the JVCs, one I used the 150 chips in and the other I used the Hitachi 394-160 chips in and both have worked fine for a few months now. The 160 chips are supposed to be a little better chip though so I'd lean towards them if you decide to replace the STKs.

I hope that helps!

If it's anything like my set you'll fall in love with how easy it is to work on - especially compared to these Sony's, though now that I know how to disconnect the focus block wire and HV wire my next Sony will go much smoother, I'm sure (if there is another one, and if I can keep away from the ceiling fan! LOL!)

Take Care,

Steve
 

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thanks steve,

JVC Model #AV48WP30

I got the stk's from an online retailer, for around $8 each, not sure the brand. So it could be the chips being poorly made. But the blue convergence is off after working perfect for months after the repair, originally the red was off before it was repaired. It actually has been back out the past few days. It only fixed itself yesterday for a few hrs.

I purchased the STK's, and brought the board to a local reputable TV repair guy, and he soldered it all together since I was not confident in my soldering skills. Very interesting. Maybe when I get the Sony 57" up and runnin, I'll start tearing this thing apart again since I plan on replacing this 48" JVC with the 57" Sony.

And giving this 48" JVC to my brother. I'll keep u updated.
 

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Discussion Starter · #31 ·
Hi Nick,

I don't know much about that model. I'm headed off to bed now, but I'll try to do a little research over the weekend. If you spend any time at all reading these forums though you'll find that the number one problem with do it yourself repairs is people trying to save a buck and buying cheap Chinese knock off chips. Simply put, they don't work! Many times they wont work from the start and even if they do they don't last long. At $8 I'd say you have knock off chips and I'll bet dimes to donuts that's your problem.

Look around on this site, Leonard wrote a very nice thread on convergence repairs and he stresses the importance of buying original chips from trusted suppliers several times . . . you will note that Leonard doesn't sell these chips, he installs them! And I'll venture a guess that he's installed more of them than you or I will ever see. He has no reason to steer us towards the more expensive Sanyo chips - he wont profit a nickle from that. All he's doing is graciously sharing his experience. I don't know about you, but when I professional takes the time to give me a recommendation and to explain the why behind it I tend to listen to him! Especially in this case. We're already saving a ton of money by doing our own repairs so why try to save $20 or so? The risk just isn't worth it! Buy quality stuff from a quality supplier and your chances of success will climb immensely!

I usually purchase STK chips from Acme. When I needed the Hitachi STKs for my JVC though I think I got them from Encompass. So far my experiences mirror Leonard's - they both have given me good parts and good service.

I just found Leonard's post on convergence repairs - it's at the following link, and pay attention to the first ten posts!

http://www.hometheatershack.com/for.../5600-crt-based-rptv-convergence-repairs.html

If for some reason you have trouble finding the Hitachi chips drop me a PM as I think I ordered an extra set so I probably have a set I could part with for ya.

As far as the soldering. This is really basic stuff - you can do it! Go to Radio Shack and buy a soldering iron, some solder, some ic sockets, and a solder pad perf board and practice a bit and you'll be good to go in no time.

Well, best get to bed as I have an early day tomorrow.

Take care, good luck in your repairs and thanks sooooo much for posting back your experiences! I'm really enjoying following your progress!

Steve
 

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Discussion Starter · #34 ·
Hi Nick,

Well, they look ligitament but anyone can print a sticker so I hope you got them from a reliable vendor (I'll bet they are though as they can claim they are real Sanyo on eBay and make just as much without having to hassle with faking stickers and stuff so it's probably not worth their trouble to go to that extent).

Do I take it that unlike the JVC repair you're going to attempt to de-solder/solder the chips into this set?

If so then good luck! I know you can do it, these aren't that bad of boards to work on.

Get the desoldering iron from Radio Shack, it's like $11 or so and works amazingly well.

Just go slow and everything will be just fine!

I'll be in and out for the next few hours so post back any updates, questions, etc..

Take care, have fun (yes, I consider this kinda stuff fun!),

Steve
 

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I was at radioshack today and saw the desoldering iron you are talking about for $11.99. For some reason I didn't pick it up since I am set on going the braid route currently.

But I did pick up a new soldering iron from harbor freight for $4, with a nice small tip.

I might attempt to remove the old SDK's tonight. Wish me luck. I will post pics of the success.... or disaster lol.

! just remembered why I went there... to get thermal [email protected] and forgot.

http://www.harborfreight.com/30-watt-120-volt-soldering-iron-47887.html
 

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Discussion Starter · #36 ·
I would really encourage you to get the desoldering iron. It just works really well.

If you're set on the hard way though . . . I would suggest clipping the legs of the chip off and then warming up the pad and plucking the legs out one by one and then cleaning up the solder on the pad. It'll go much faster than trying to get all the solder on those pads to let go of the chip legs so you can pull it out. Now with the desoldering iron they literally fall out for ya . . .

Good luck, have fun!
 

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Well, after forgetting the desoldering braid at the house today on my way to a friends to help me, I stopped at radioshack and broke down... getting the desoldering iron. Also, heatsink compound.

Well, that was the best $12 I've spent in a while. For a guy that has never desoldered anything in his life, it took me 10 min to remove those SDK's. After using that tool, I can't imagine using braid. Next will be installing the chips tommorrow.

And I had to stop by home depot on the way home since my buddy told me the solder I had was too large, not meant for circuit boards.

So I got some thin gauge stuff. Should be all set. He tested all the resisters and they read ok on the multimeter. Now I just have to check the 2 on the other board like you were saying.

What is a good way to remove the old compound from the heatsinks? thanks.

 

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Discussion Starter · #38 ·
Hi Nick,

Yeah, that $12 desoldering iron works great! It's not often things work as well as you think they will, let alone better than you think they will!

The solder I use is .062" diameter. Remember to place the tip of the iron so you are heating the solder pad and the leg of the chip on one side and then just touch the solder to the pad and chip leg from the other side (so you're melting the solder on the pad and leg and not on the tip of the iron) and it should flow right onto the pad and up the leg and make a nice Hershey kiss lookin' kinda thing for ya. If I recall correctly in just a couple spots there's some surface mount components kinda close to the solder pads - I always put the iron on the side opposite of those.

To accurately test the resistors you have to desolder one leg and pull it up. I wouldn't worry though, it seems these boards are well protected by the pico fuses and so far I think I've only seen one thread where someone had a bad resistor so the odds are they are good.

The pico fuses you can check in circuit - and do remember to check the ones on the G board!

To remove the old heat sink compound I use a utility knife blade by it's self = just place it flat across the heat sink and at about 45 degrees tilt and try and scrape off as much as you can. Then I use alcohol and a paper towel to wipe off the residual.

The right amount of heat sink grease is "just enough". Clear as mud, eh? ;-> You want enough to completely cover the back but you don't need it very thick - just a thin layer and just enough to cover the entire back of the chip completely. Too much grease can actually decrease the thermal transfer. I tighten the mounting screws down "firmly" I dunno how yours were but mine were just barely "snug" from the factory, they were almost what I would call "loose".

It sounds like you are on your way! I'm betting we'll have a "wooo hooo it works!" post tomorrow night!

Take care, good luck - keep us posted!

Steve
 

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Here is side by side the JVC 48" (behind), and the big daddy 57" Sony in front. I couldn't beleive how big this thing was until I got it in the room. A monster compared to the JVC. But, better in my room than in the scrap yard or someone else's.



Uploaded with ImageShack.us

The soldering was a success. It was not that difficult after viewing many videos online. Tested the 2 fuses on the other board, they read OK. So it was just the chips I guess since it is working flawlessly. Also, I noticed when taking out one of the SDK's that 3 pins looked overheated and burnt. Maybe that is where it failed.


Seriously, I did not time the picture for a football picture. It just happened. .


Uploaded with ImageShack.us

Now, slr, would you reccommend anything else I should adjust or 'reset' the settings? thanks. ps. those beers tasted even better knowing I fixed this thing for $20.
 

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Discussion Starter · #40 ·
Outstanding! Congratulations Nick! It's just nice to win one ever now and then, isn't it? :highfive:

$20??? You get Sanyo STKs much cheaper than I do!

I don't have anything specific to offer beyond this as this is about as far as I got with my repair. The only other thing I can recommend would be to clean the optics as the CRTs are dust magnets due to the hv in them. It's up to you though, if it looks fine then it wont hurt anything to leave it, but it'd probably brighten the pic/colors up a bit.

To do it properly you would need to:

*) Remove the back cover and that filler piece behind the CRTs.

*) Look to your right up in the lower part of the projection chamber and you'll see the wires going to the auto convergence sensors. Follow it back down and you'll see it plugs into the A board (big board just to the right of the D board you just repaired). Unplug it. Then follow it up and you'll find it's secured with plastic covered wire that's anchored to the sides of the projection chamber. Just undo those so the wire flops free and then gather it all up and secure it with a wire tie or rubber band.

*) Undo the front panel, the screws are on the back lip of the case. Pull it off and set it down a bit. You can't take it all the way off because it's got some wiring ran to it too but it'll come loose enough you can pull it off and set it down enough to get to the screen screws.

*) Now undo the screen retention screws - they just run around the endges of the screen. Have some help as when you undo the last one it'll want to come off. It's doable by yourself if you realize that'll happen - save the last screw for the center one to make this easier.

*) Now just pull the screen off while being careful of the bundle of auto convergence wires.

*) I used compressed air to blow as much off the CRTs as I could, then I used SprayWay glass cleaner on the CRT tubes (got it at Walmart). Careful! It puts out a ton when you press the nozzle so just a quick shot! DON'T get a ton on there and have it work it's way down into the lens pack! (it shouldn't since it's a foaming cleaner). I ordered some microfiber clothes off fleaBay for this. I used a microfiber cloth and just kinda rolled it as I wiped it so it always had a fresh cloth surface. Sounds hard, but it's really easy.

*) They say that mylar mirrors stay clean and you can easily damage them so to leave them alone. I wasn't sure what was in this so I shined a light across it and it looked clean so I left it alone. The mirror is thick and I don't think it's mylar. Later when I still had the little flaw in the screen I decided to clean the mirror. I put a big bath towel over the CRTs and the exposed boards below and then I used compressed air to blow the mirror off and then I used the SprayWay and a fresh microfiber cloth. Although it looked clean there was a ton of grime that came off on the microfiber cloth.

*) On this unit I used an alcohol/water/Kodak Photoflo mixture to clean the back of the projection screen as that was what Leonard recommended. I again used a fresh microfiber cloth. Again, it looked clean but a ton of grime came off on the microfiber. This unit had been in a storage shed for a long time though and it was incredibly dirty inside so your mileage may vary.

When I put it back together the picture was blazing! It looked good! Except for the dog gone flaw in the middle! I never did figure out where it was from as I went a step further and separated the front screen pack and that's when I broke the lenticular lens.

The optics cleaning did such an improvement on the Sony that I did it to my JVC and it really helped it too. Teh JVC looked good before I started so it wasn't a night and day difference, but it was definitely noticeable so it was worth the effortin my opinion. In the JVC I was lazy and just used the SprayWay on the back of the projection screen and it seems to have worked fine there too.

As far as settings . . . on Yahoo Groups there is a WS500 group that has some settings listed. That model is very similar to ours so I was thinking of trying them but I never got that far so you're on your own. I don't have them handy so you'll have to chase after them yourself. If you can't find them post back and I'll dig further when I'm on my other machine.

Soooo, kick back and enjoy your beer and new tv or spend a little more time on it and probably increase the picture quality a tad - it's your choice. If you decide to clean the optics post back how it works out for you.

Again, glad you got it up and running - congratulations!

It's been fun corresponding with you, hopefully we'll have another chance in the future (is the JVC next? If so start a thread on it!), take care,

Steve
 
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