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Discussion Starter · #1 ·
I'm new to the forum and have seen some info on my particular tv. It seems I have a convergence problem like so many others. I just opened up my tv and did some snooping around; it took a some time before I located the suspect IC's. I have 1 each of STK392-110 and -150. I looked at the resistors around the IC's and didn't notice any of them burnt. I also ohmed them, but I didn't have reference sheet to go by. My chassis is a DP23. I don't know if the resistors are the same as on a chassis DP25. Any help in that area would be appreciated. Also, I was going to remove the board with IC's, but i couldn't figure out how to remove the 3 thick gray/black wires going into the power supply/transformer. I didn't want to pull on them without know the right way first. Thanks for replies.
 

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The service manual is the reference for the values. There are several sources for manuals in the sticky in the DIY Repairs forum, as well as in the vendor listings.

You should not need to remove the 3 thick gray/black wires to complete the repair.
 

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Discussion Starter · #3 ·
lcaillo - thanks for the info. About the 3 wires & transformer they hook into. I removed the mounting screws that secures the transformer to the board, but it wouldn't budge. Is it supposed to come off or does it have connections soldered to board? The reason why I ask is that the board has to come out of the TV to replace the components, but if I can't get the transformer out of the way...:huh: Thanks again.
 

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It is NOT necessary to remove the transformer nor the wires that go into it. The transformer is soldered to the board. If you cannot figure out how to manage the dissassembly to change the parts, I suggest that you do not try to DIY.

As noted in the sticky in the DIY Repair area, it is beyond the scope of this forum to give step by step instructions for repairs. There is an enourmous amount of information here and resources to find more. If that is not sufficient, you are not a good candidate for a successful DIY repair.
 

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Discussion Starter · #5 ·
While I appreciate the advice, I am proficent at soldering and component replacement on circuit boards. I only asked because I don't work on TV's for a living and needed a little guidance from a more experienced technician. Secondly, I wanted to get the board out as far as possible for the best working environment as I'm doing this repair where the TV sits and not in a workshop. If I can remove the board completely, I could take it to work and repair it there. Thanks again for the info on the manuals and parts.
 

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The Hitachi anode leads (which are presumably what you were describing) generally require a push and turn of about 90 degrees. Experienced techs know that it is better not to remove them if possible for a number of reasons. A connection with voltages at 30kV has to be made well to prevent arcing, dangerous conditions, and severe damage. It is very easy to damage the connectors if you are not familiar with them. My recommendation, once again, is to not remove them.

If you are familiar with electronics repair you should appreciate the unintended consequences possible that can make a repair very complicated when you are outside your area of expertise. This is why we only deal with common routine repairs and give limited advice on how to keep it simple.
 

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Discussion Starter · #7 ·
Is there a kit that'll work for chassis #DP-23? Will any of those listed in you DIY Repair Forum work? I called a couple of the companies listed and they can't tell me if there is one for my TV. If I have to, I'll order them individually.

Thanks
 

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If it is not listed, then there is not one. All of the kits are listed. The only difference in the kits are the resistors. Since Hitachi does not have a kit for it, it may be safer just to use the STK392-150.
 

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Discussion Starter · #9 ·
Thanks for the info. Also, have you had much experience with UED parts? I was about to order 2 IC's from them, but I want make sure their parts are ok.
 

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Assuming you mean Union Electronics Dist., they are very reputable. Many reputable vendors have been burned by bad chips over the years, however, so I stick with B&D, Acme, and Electronica (not electronics).
 

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Discussion Starter · #11 ·
Ok, Thanks again. Hopefully after I replace those IC's and do the adjustments (I downloaded the service manual), I'll be back up and running. Later.
 

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Discussion Starter · #12 ·
I'm working on my TV right now. I desoldered one of the stk's and removed the 2 screws holding it to the heat sink, but the thing won't budge. I scraped away the excess heat sink compound and slathered some alcohol around the edges with the hopes of getting behind it and loosening it. I tried prying it a little, but I don't want to pry too much and break something. Any ideas on an easy way to pop the thing off? Thanks!
 

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Hammer and chisel work nicely...
 

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Discussion Starter · #15 ·
lcaillo - I know I mentioned removing the 3 wires from the transformer before, but I really think I need to remove them now. I have some board repair to do, i.e replace eyeletsand some short run repair. I must have overheated the contacts when soldering in one of the new stks. I didn't realize they were so sensitive. I didn't apply the heat for an excessive amount of time, or so I thought. I need to remove the board from the TV so I can work it under a microscope. I just had a micro-miniature soldering class a couple of months ago so I know what I have to do. I just can't do it on the floor of my bonus room. You said usually it's a push and a 90-degree turn. Which way do I turn them? They have a rubber boot over the connection. Do I turn them there? I know I'm taking a big risk unpluging something that I shouldn't have had to do in the first place, but I don't see another option. I'm definitely not lugging the whole thing downstairs to be taken to a shop to get repaired. Please let me know any ideas you have. Thanks!!
 

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Slide the rubber boot back, then push down and turn the wire 90 degrees either way. It should release. If not, try the other direction. If it does not release change the amount that you are twisting, but make sure you are pushing down as you twist, not pulling until it comes freely. If you apply pressure to pull it out, you will open the metal bits that catch on the plastic retainers and you will have no choice but to force it out and you may break the connector or damage the inside of the FBT.

Personally, I would fix it in place. Remaking a couple of traces is just not that big of a deal with boards with traces this size. You can overlay a fairly large wire on the location of the damaged trace and solder it down and have a stronger connection than the original one.

You need to resolve your soldering technique before doing anything, however. If you lifted traces on this board you are likely applying heat for far too long. This is often due to using an iron that is not large enough or hot enough to complete he job quickly, or having contamination or a tip that is oxidized. These are not fragile boards. If you botrched it you need to rethink what you are doing.
 

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Discussion Starter · #17 ·
I finally got the repairs done. I looked at the adjustment section of the service manual and it said to do the adjustments in order. Is that really necessary since I don't want to tweak things that don't need to be and probably shouldn't be? Can I just do the convergence part? I was able to look at the grid pattern and the blue is pretty much the same as it was before. Thanks
 

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You do what needs to be done. I you jus need touch up you do that. If you have to do a full alinment from scratch it is very important to do it in the order provided.
 

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Discussion Starter · #19 ·
First off, thanks for all the valuable insight and information you have provided here; I wouldn't have attempted this repair without it. I finally completed the portion of the adjustment my set needed...or so I think. The picture is back; it looks like it did before the convergence issue. The only thing is that I have a narrow, yellow, horizontal line through the middle of the raster. During some TV programs you don't notice it, but during others you see it very well. I must say the service manual must've been written by an engineer expecting only engineers to use it. Some of the flow charts and procedures are a little hard to follow; needless to say I didn't attempt them if I didn't understand them. Any ideas what may have caused the yellow line? Thanks again for all the help.
 

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Collapsed image causing a very intense illumination of a line likely burned the blue phoshor. You may have an open (or intermittent) connection in the blue vertical deflection circuit. Sometimes, repeated use of the set with a convergence problem can cause burned phosphors if the distortion in the image creates a very intense compressed area.
 
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