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Discussion Starter · #1 ·
Hi Guys,

I just picked one of these units up. I wasn't really in the market as I'm pretty busy right now but it was just too tempting - literally the conversation went like "we're moving tomorrow and we're NOT moving a big, heavy, broken TV - come and get it"!

I picked it up but had to store it in my folks's garage as I was already working on a 51" set of the same model for a friend (these things are kinda like cars, there's just so much parking space available! ;->).

I have the 51" fixed and it's off to it's new home so this one will be finding it's way over here shortly so I thought I'd start a thread on the project.

The owners said they had it looked at and it was a convergence issue but they couldn't afford the fix and they did describe what a convergence problem looks like. I haven't fired it up yet so I'm not 100% sure it's a convergence issue -> I learned a long time ago that when you service stuff confirm what it's doing for yourself before you start!

I'm just gathering information for the project right now and am just assuming it's a convergence issue.

I found a service manual at this link (scroll down to find it):
http://www.techlore.com/group/2/list_downloads

It doesn't have the schematics with it though, if anyone has a link to the schematics please post it for me.

Doing a little research on this series it seems the following are the common failure items in the the convergence circuit:

(2) STK392-560 Convergence ICs

I noticed that Acme does have the STK392-560s. They also have the following:

STK392-570 Imitation
High quality Chinese imitation
We guarantee these to be as
good as the original Sanyo ICs

Also replaces STK392-560
90-day Warranty
Mitsubishi # 267P150010

I've read a few posts at various places on the net that recommend the 570s over the 560s as the 560s are 5 amp rated and the 570s are 8 amp rated and are compatible for use in 560 circuits (and I note that Acme even says "Also replaces STK392-560"). I noticed that Leonard doesn't have that sub noted in the convergence repair sticky though, so I gotta ask . . . What's the move here, real Sanyo 560s or imitation 570s that Acme is putting their reputation behind and claiming are as good as the Sanyos? Have the 570s proven to be a viable sub for the 560s?

(2) 5 amp, 90V IC link fuses

PS5001
PS5002

These are on the "G" board that stands vertically to the left of the "D" board that has the convergence ICs.
These are "IC Link" type fuses from the factory but pico fuses can be used.
From what I gather at least one of these almost always goes out.

(6) 3.15 amp, 90V IC link fuses

PS8001
PS8002
PS8003
PS8004
PS8005
PS8006

These are all located on the "D" board.
These are "IC Link" type fuses from the factory but pico fuses can be used.
I've noticed some use 3.5 amp in leu of the 3.15 as they are easier to find but Acme has the 3.15 amp ones so I'll stick with what was stock.
From what I gather these don't go out as often as the 5 amp ones on the "G" board but they go out often enough that they MUST be checked.

(30?) 4.7 ohm, 1/2watt, metal film, 1% resistors.

R8045
R8046
R8051
R8053
R8059
R8060
R8063
R8064
R8066
R8067
R8069
R8070
R8073
R8075
R8078
R8079
R8081
R8082
R8085
R8086
R8089
R8090
R8091
R8092
R8093
R8094
R8097
R8098
R8105
R8106

It seems from what I've read that burnt resistors are not as much of a problem on these sets, the bigger problem is blown IC link fuses. Do I take it that those fuses usually blow fast enough that they usually save the resistors?

I can't find specifics on which resistors commonly fail, all I've found is some posts where people have made the STK & fuse repairs and are still having problems - they are usually directed to "check the resistors near the STKs". A couple posts I found though did mention 4.7 ohm, 1/2 watt resistors as the ones to check (but didn't list their parts designations or quantity). What I've listed above are the 4.7 ohm 1/2 watt resistors I found in the service manual under the "D" board parts listing. Again, schematics would be nice if anyone has any.

The 4.7 ohm 1% resistors are kind of hard to find too - they spec 1% tolerance and I'm assuming there's a reason for that so I'd like to adhere to it, finding 1% tolerance in this ohmage and wattage is not easy though! I imagine one could go up in wattage, though I don't like to. I suppose if one couldn't find any 1% tolerance they could buy some 5% and just use an accurate meter and select the ones that were within 5% tolerance (i.e. between 4.65 and 4.75 ohms).

Does anyone have any input on the resistors? There are some lower value, fairly high wattage resistors on the "D" board listed in the manual - do they need ohm'd out too?

The only other thing I see that's a bit different than the other convergence repairs I've done is that the flyback transformer that supplies high voltage to the hv block is on the back of the board that has the convergence ICs. I just recently unhooked some HV cables doing a repair on a Sony so I'm confident I can unhook the hv cable without damaging it, but I'm also taking note that Leonard and other techs on other forums have posted they don't mess with unhooking and potentially damaging the hv lead, they just uhook everything else and then carefully flip the board over and work on it in the set so I'm going to follow their lead and attempt to do the repair in set (I'm picking up that there's enough of a risk of damaging the hv cable that it's best to not mess with it unless you have to - even for an experienced professional). If it proves to be too uncomfortable for me then I'll unhook the hv cable and remove the board so I can work on it more comfortably (I really like working at my nice comfy work bench rather than squatting on the floor!), but the plan is to try to put up with a little discomfort and save me a potentially self-inflicted problem.

As I work on the set I'll try to take pics and do some follow up posts.

Take Care,

Steve
 

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I would use an original 560 before using a copy of the 570.

Some Sony sets have had problems with related parts including the convergence generator. I have found some with excessive correction or d.c. offset.
 

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Discussion Starter · #4 ·
Hi Leonard,

My inclination was toward an original part too and I wouldn't even have considered a copy if it wasn't from Acme, they have such a good reputation and my experiences thus far have been excellent so I put a little more weight on their statements than I would other vendors.

I'll do a little research on the dc offset - thanks for the tip!

We'll see if I need to go further and check the convergence generator if the STKs don't fix it.

This set was truly a gift so again, no pressure - if I fix it fine, if not I'll part it out and haul what people don't need to the dump (I saw a recent post on another forum where someone needed the screen so if it needs extensive repair I'll just help him out rather than spend tons of time trying to repair it).

I'll post more after I pick it up and actually get to plug it in and see what's going on with it.

Take care,

steve
 

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Discussion Starter · #6 ·
Hi Guys,

Just a quick update - we moved the beast over to my place tonight. Those chest handles I put on either side worked SWEET!!! It was a snap to move when you have something to hold on to!

There's one minor issue - it's got six casters under it and two have the wheels missing and one's got the stem bent terribly. I looked around town and didn't seen any that small, but I'm thinking I may remove all the casters and just use soem blocks with those teflon sliders. One thing that's annoying with my 56" JVC is that when I pull it out of the entertainment center to hook stuff up and then slide it back in it's kinda hard to get it centered left and right again as you gotta get the casters turned the right way - with the sliders that wouldn't be an issue at all.

And, yes, I've now confirmed it's a convergence issue so I'll get parts ordered for it and post back as I dig deeper into it.

Take Care,

Steve
 

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Discussion Starter · #7 ·
Hi Guys,

My parts are still on order and I’ve got a lot of overtime this week but I was still itching to get to work on the new set. There are a couple pico fuses on the “G” board that frequently get blown when the convergence ic’s go out so I thought I would remove the G board today and check those fuses.

I’m not claiming this is the best, only, nor safest method – it’s just the one I used. You’re responsible for your own safety!

The G board is mounted vertically to the left of the D board. Removing it was pretty straight forward with only one minor surprise that I’ll get to in a bit.
 

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Discussion Starter · #8 ·
There’s a bundle of wires that runs along the back of the set and to the various boards. Tied in with this bundle is a ground wire that goes up to a metal cross member by the HV Bloc, CRTs, etc.. It’ll kinda put a tether on the bundle while you’re trying to unhook things so unhook it first.
 

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Discussion Starter · #9 ·
There’s a red wire that’s larger than most but smaller than the wire that feeds the HV Block that comes out of the Flyback Transformer. I believe it’s called the Focus Wire. It’s longer than it needs to be and the excess is gathered up and held by a couple twist retainers on the back of the G board. I put a loose wrap of masking tape around the bundle and then removed it from the retainers.
 

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Discussion Starter · #10 ·
Now you can undo one or two of the wire bundle retainers and remove the G board retainer screw and slide the G board towards you and then lift up and it’ll come right out. I’m sure one could simply remove the metal back panel and probably get to any solder points you would need to without removing any more cables but I prefer to work on things at my nice comfy work bench rather than on the floor so I proceeded to label and remove all the cables and then the board from it’s plastic mount.
 

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Discussion Starter · #11 ·
Removing the cables was straight forward with the exception of one surprise. Connectors CN5005 and CN5006 are standard spade push on lugs. CN5005 is on the lower part of the board towards you and it came off with just a bit of effort. CN5006 though wouldn’t let go and I could see the lug wiggling in the board! I removed all the other cables, the metal back piece (four screws and it comes off), and popped the board out of it’s plastic carrier (four screws hold it in and then there are five plastic tabs you gotta depress to get the board to come out of the carrier) and then I could get to the solder pads of that lug. The pads looked different, the solder was a flat paint kinda finish, just looked porous/rough and I could see the lug pins moving as I wiggled the lug. I used my de-soldering bulb to de-solder the lugs and it came out of the board. Then I grabbed onto the lug with a pair of needle nose pliers and pulled on it and the lug and socket separated. The pc board looked fine so I inserted the lug and used some duct tape to hold it in place while I soldered it back in. I’m glad I did go a step further and remove the cables as I’m sure this would’ve caused some kinda problem in the future. Makes me wonder how many other such joints are lurking in there!

Once I had the board out and repaired I tested the two pico fuses on the board. In circuit PS5001 would start out at around 50Kohm resistance and then slowly bleed upwards towards infinity. I figured the fuse was blown and a cap somewhere in the circuit was causing that behavior. I pulled the fuse out and tested it and sure enough it was blown. Testing PS5002 in circuit showed a direct short so that fuse appears to be good.

I see there’s an MCZ3001D chip in the upper left corner of this board. It’s one of the chips that likes to fail in these sets so it’s tempting to replace it with a MCZ3001DB chip while I have it out, but I’m resisting the urge as it’s best to fix just one problem at a time. It’s not that hard to pull this board so if it goes out in the future it’ll be a pretty minor repair so there’s no real need to do a pre-emptive strike on it.
 

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Discussion Starter · #12 ·
That’s as far as I got today. I probably wont get to the D board until next weekend. I’ll try to take some pics as I work on it, though I really suck as a photographer.

Any and all comments, tips, suggestions, questions are welcome – I’m trying to make this as clear as possible!

Take care,

Steve
 

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Discussion Starter · #13 ·
Hi Guys,

I've been working a lot of overtime lately but I had today off, so last night when I got home I figured I'd start on the repair and then finish it up in the morning. Yeah, well, that's how it started . . . Once I labeled and pulled all the connectors I figured I might as well pull the board. Once I'd done that I figured I might as well de-solder the chips . . . yeah, you see where this is going -> I didn't get to bed until 5am this morning!

Unfortunately the camera batteries were dead so I didn't get any pics taken, but this is a pretty straight forward repair so I'll just make a couple comments.

*) There are six screws that hold the board down. Five are easy to see but one sits behind a heat sink back by the flyback transformer and is hard to see. I couldn't find a good pic of that location on the net so I pulled a copy of the board drawing from the service manual and highlighted the screw locations and noted where the one hides.

*) There are some flip up connectors along the right edge of the board. They are easy to flip up - just pull up and wiggle a bit, and they snap right back down when you put it back together. One of those is CN8005 which I believe you can use to check the DC Offset to the STK chips. I snagged a couple pics of those off the net.

*) The screws holding the STK chips to the heatsinks were surprisingly loose. If you could get a grip on the screw head with your fingers I'll bet they were finger tight! When I installed the new ones I snugged them up tight (just tight, I didn't torque on them or anything).

*) I replaced the original STK392-560s with STK392-570s from Acme in Orlando, FL. They are rated for a little higher voltage/amperage so hopefully they'll last a little longer. They seem to be a good sub as when the tv was turned on the convergence was spot on.

All in all it wasn't a bad repair, though I do NOT like soldering on the floor! It's just not comfortable for me.

My set only needed a 5 amp pico fuse on the G board, PS8001 and the STK chips. All the other pico fuses and resistors were fine.

My only issue now is that the picture looks kinda hazy/washed out. I think the lenses, mirror, and screen needs cleaned though as this unit was extremely dusty inside and out (it'd been in a storage unit for a very long time). I used a shop vac to suck as much as I could up and then gently used some compressed air to get into some tight spots and vac'd again but I didn't spend much time on the projection area. When I turned it on I thought I had a broken lens or something as I had a crack like looking thing on the screen but then I surmised that it was a cob web throwing a shadow across the projection screen!

I'll clean it up and post back if that helps or not.

Take Care,

Steve
 

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Discussion Starter · #14 ·
Well I slept tonight so I didn't get time to clean the unit up.

I ordered a couple microfiber clothes from Acme when I ordered my parts so I'll use them.

For cleaners I've read cleaners with ammonia in them are a no-no as they can cause clouding on plastics, but I've read conflicting things on cleaners with alcohol in them - some say yes, some say no.

What's the move here Leonard?

Would my Mom's old stand-by of vinegar and water with just a drop of soap be appropriate?

Thanks!

Steve
 

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Sprayway is easy, effective, and safe on the mirror and lenses. I don't like to use it on the screens because I have not tested it on them. I use a mix of 1 oz isopropanol, 1 oz Kodak Photoflow, in 1 qt water and it has been tested safe on everything except some of the recent anti-glare coatings on PDPs and LCDs. A small amount of pure isopropanol is fine on everything in your set.
 

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Discussion Starter · #16 ·
Thanks Leonard!

For those reading the thread later - I found the Sprayway glass cleaner at my local Walmart, it ran around $5. I'm going to have to order the Kodak Photoflow off the net though.

/Steve
 

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Discussion Starter · #17 ·
Hi Guys,

I'm at a stand still as I'm waiting for the Kodak Photo-flo to arrive. The Microfiber cloth I got from Acme was pretty tiny too so I ordered some man sized ones.

It'll be mid-next week before I get to cleaning this.

We picked up some batteries for the camera - does anyone want me to take pics and a do a write up of the process? If not it'll go quicker for me, but I don't mind taking a little time to snap pics and stuff if someone benefits from it.

Take care,

Steve
 

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Discussion Starter · #18 ·
Hi Leonard,

I've been doing a little research on cleaning the unit up and I've seen a couple references to "deep cleaning" of the lenses. Basically it's said there's a stack of lenses on top of the CRTs and Sony doesn't seal them up so over time dust can get into the lenses below the final exposed one. They don't need deep cleaning as often as they do normal cleaning, but I've seen every 5 years or so given as a rule of thumb a few times. This unit is 7 years old and it's really dusty inside of it so I'm wondering if it wouldn't benefit from cleaning the entire lens stack.

Unfortunately I can't find any good descriptions on how to do that, no pics, nor anything. The service manual just lists the lens (part 108 on page 85) and doesn't show a break down of what's in it.

It looks like it just screws onto the end of the CRT, but I'm imagining it'll have some sort of focusing aparatus and stuff in it so you'd have to be extremely careful and pay close attention when disassembling it and after it was done you'd have to refocus it?

I'm wondering how often it really needs done as though I've seen references it's curious there's no good directions or pics anywhere, that kinda tells me it's not done often . . . of course just because it's not done often doesn't mean it shouldn't be, soooooo I thought I'd ask the guy who sees a ton more of these than I do and get his opinion, so here I am! 8->

Thanks!

Steve
 

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It depends on the set and the environment. Clean the front lens and mirrors first and see what that gets you. You can look into the lenses with the set on and contrast turned down some and see if you see any debris or haze on the back lens or crt face. If it looks clear, don't bother. If you see stuff, the lens is held on by four screws. Be sure to pull the ones that hold the lens on and not any mounting screws or the ones that hold the coolant chamber to the crt frame.
 

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Discussion Starter · #20 ·
Hi Leonard,

All my stuff came in and I had a little time today so I tore the thing apart. It went fairly well so about the only comment I have for future readers of the thread is that there are sensors for the auto convergence mounted around the screen so consequently there's a wiring harness running to the screen. I found it was best to remove the back and just unhook that harness from the circuit board. I bundled it up and used a rubber band to secure it so I didn't have a big pigtail to deal with. Beyond that it was pretty self explanatory.

It worked beautifully! The screen is crisp, clean, bright, and the colors look good! The lenses were dirty and the back of the front screen was pretty dirty too. The mirror seemed good though so I originally left it alone.

I've just got one problem though - there appears to be a piece of lint or something somewhere in the optics. It's hard to see as it only appears with certain colors, but unfortunately one of the colors is flesh tone and it's in the middle of the screen so it is noticable when watching a close up facial shot.

I tried covering the lenses to see which gun it was coming from. Covering blue and green didn't seem to help, but covering red did but my wife said the picture was pretty dark when I covered it so that may be why it disappeared. I pulled the lens pack off the red and I wont say it's clean, but it's not terribly dirty either. There is some small specs visible but I didn't take the lens apart. Actually on a quick look I didn't see how - are they just held in by the rubber around the edges? I cleaned the upper and lower lenses and gave the CRT lens a spritz of compressed air to no effect. I even rotated the lens pack figuring if the debris was in the lens that would move it's position - it didn't so I'm thinking it's not in the red gun but rather red just illuminuates it well.

I hadn't cleaned the mirror as it looked good when shining a flash light across it and I'd read some had synthetic mirrors that were easily scratched. I gave it a quick shot of compressed air though but it didn't help either.

I pulled the screen again and cleaned the back of it again but again, no joy so while I had the front off I went ahead and cleaned the mirror - it was clean as I didn't get a thing on the cleaning cloth and I didn't scratch it up so it looks like it's got a glass rather than mylar mirror.

I'm thinking it's in the front screen stack so I probably need to pull the screen again and unstack and clean it. I was hoping I didn't have to do that since it's so well covered I was figuring dust couldn't get into it easily but I guess I'm wrong.

It seems to be a problem for all three guns, so that pretty much narrows it down to the mirror and front screen stack . . . sound like I'm on the right track?

TTYL,

Steve
 
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