I found a couple pics of the "D" and "G" boards on the net that are helpful.
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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.
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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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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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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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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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.
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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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
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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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
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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