Sony Kp51WS500 really stuck

Do you have power to the ICs? Check the fuses in the power supply? Why are you even bothering to look at it without a schematic?

Leonard

There is a bad picofuse on the power supply board. I previously mentioned this possibility in addition to the fuses under the heat sinks.

quote:

"There are some Sony models which get a bad picofuse on a separate power supply board when the convergence amps fail, in addition to the picofuses hiding under the STK's heat sinks"

Anyway, I looked at the schematic. The fuses are PS5001 and PS5002 on the G board which mounts vertically to the left of your convergence board. Little green 5A picofuses. Only one is usually bad. They are shown on page 76 of the service manual.

Mark Z.

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Mark:

I agree from my reading of extensive discussion at the TECHLORE.com site. Therer apparently are two (2) PICO Fuses on the G Board that you haver to check also.

Several indepth articles and discussions on the OSNY convergence problem, these STK you reference , etc. there. It's a plu, for sure, but only because it's the best info site on these issues I've found.

I'm repairing my SONY KP-61XBR38 convergence issues now. My set uses different boards and ICs so it's not as cookie cutter.

Also, the moderators from that site have their own REPAIR KIT website (tvrepairkits.com) where they bundle all the typical parts, paste, and INSTRUCTIONS into a kit for hobbyist use.

Hope this helps.

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You were very clear Mark but I missed that part of your reply. I saw the vertically mounted board on the left side. I never checked it thinking that all pertinent fuses would be on the deflection board. I remember thinking that there may be a fuse on that board. We'll give it another shot next week. BTW, what is the trick to removing the HV wires? Thanks, Lenny.

On Fri, 5 Jun 2009 14:42:41 -0700 (PDT), " snipped-for-privacy@yahoo.com" put finger to keyboard and composed:

I posted this in the previous thread ...

There is an 11 part service manual here:

- Franc Zabkar

I didn't notice that was the service manual for this model. Thanks very much Frank for that info. On another NG it was mentioned that I should not have run Auto focus. After replacing the chips that convergence should have been adjusted via service mode. Now by having run autofocus as I did after chip replacement did I get the set in such a way that now changing these fuses won't correct without some major re alignment procedure? Lenny

We have another guy in the field who brings me these boards. There is a tool he uses to get the high voltage leads out, but can use a drink straw in a pinch. The straw is slit so as to go around the red wire, pushed down into the FBT so as to get between the flanged cap on the wire and the surrounding inner part of the FBT. Pretty tricky though - I hate that kind of thing. On the rare occasion that I work on the whole TV in the shop, as I recall, I dismount the HV splitter which allows me more room to stretch the wires, and just do the soldering etc while sitting there on the floor.

I don't think you need to do this though. Just pull the power supply board, which does not include the FBT, and replace the picofuse(s).

Mark Z.

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The old drink straw trick. I remember that kind of tool. We used something like that to remove pins from Cannon connectors on the flight computer chassis on the C141A. It was made out of tough teflon as I recall. That was 40 years ago though so I don't remember much.....I can try the straw. Thanks. What do you think about the other part of my question though? Do you think I'm in trouble? Lenny..

I didn't notice that was the service manual for this model. Thanks very much Frank for that info. On another NG it was mentioned that I should not have run Auto focus. After replacing the chips that convergence should have been adjusted via service mode. Now by having run autofocus as I did after chip replacement did I get the set in such a way that now changing these fuses won't correct without some major re alignment procedure? Lenny

Running auto convergence makes no difference at this point.

Leonard

The old drink straw trick. I remember that kind of tool. We used something like that to remove pins from Cannon connectors on the flight computer chassis on the C141A. It was made out of tough teflon as I recall. That was 40 years ago though so I don't remember much.....I can try the straw. Thanks. What do you think about the other part of my question though? Do you think I'm in trouble? Lenny..

You don't even need to remove the anode lead. I do these all the time. Just rotate the board with everything disconnected except the anode and focus leads. Just be gentle and don't pull on them.

You should not need a tool for these if you never yank on them before trying to remove them properly. Just push the wire in, twist it about a quarter turn, and it should come out easily. If you pull on it first, you spread the clips and even the straw trick may not work.

What most people miss on these sets is that they almost always have excessive d.c. offset of 200-400 mV on the inputs to the ICs from the DCU, which results in about the same on the outputs. It is best to keep the offset lower. My rule of thumb has always been less than 100mV.

Leonard

I forgot about the twist trick!

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I went over to the job toay and found one open 5 amp fuse in the power supply board. I replaced it with a small 5A 32V glass fuse and even before I ran auto focus the picture looked good. Thanks to everyone for all the assistance. Lenny

I went over to the job toay and found one open 5 amp fuse in the power supply board. I replaced it with a small 5A 32V glass fuse and even before I ran auto focus the picture looked good. Thanks to everyone for all the assistance. Lenny

Lenny,

Power supply checks should be routine when servicing electronics, as should having the proper documentation. Some suggestions for sources for manuals and schematics are TechData and TechAssist. There are also places to find model specific tips such as Winstips and the two sites above. For a few hundred dollars a year a shop can have access to virtually any manual needed and hundreds of thousands of specific tips on repairs. There are also many free sites with less breadth in their databases, as well as lots of DIY sites that have useful information. Personally, as a professional, I would be embarrassed to have to ask for such information without having searched for it online first.

I don't mind helping other techs, or even consumers, but one should be able to do some basic research rather than having others do it.

Leonard Caillouet

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If my original question seems like I just jump in and it has offended you I appologize. I usually don't just ask. I generally try to do a search first but I also appreciate talking to fellow techs who have gone down the particular road I'm planning to travel as well. Its a little more reassuring that way. We're all just trying to pay the bills here and everyone's input is both valuable and most sincerely appreciated. Lenny.