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Discussion Starter #1 (Edited)
Updated: Hitachi 51WX20B Convergence questions :) new chips installed

Our TV Hitachi 51WX20B has gone wacky today. The 51Wx20B has a DP27 / 27D chassis. Unfortunately we cannot afford a new TV, just not there now with all the other things going on.

I've read tonight until my eyes are blurry, being 62 it doesn't take much as I can't see small print like I could at 18. That said, the issue is a convergence one where the GREEN lines bows to the right at the left and right hand sides but is centered with red and blue in the middle to make white. After seeing all the convergence issues in threads it is probably worth a try fixing it. The techs in this town are not the best in attitude. So perhaps I shall make a go of it myself I think. The problem is that many links in the early threads no longer work and some of the companies listed that sell the chips are showing substitutes. I also do not know which resistors are needed - it will be hard enough to read the colors when that time comes but I remember the rhyme :)

The board has in the following parts on it according to the schematic as best I can tell - please note that the values are from the manual not colors on the resistors:

Chips:
IK05 = STK 392-110
IK04 = STK 392-110

Resistors in the circuit from the schematic: (this post has been edited to show values read with an ohm meter and verified with color code on resistor as that is supposed to be value. All 1 watt tested at color code value, gold band.)

RK43 = 220 RS2J Metal Ox 220 Ohm 2W
RK42 3.9 1W Metal Ox 3.9 Ohm 1W actual 3.9 ohm
RK47 150 RS2J Metal Ox 150 Ohm 2W
RK46 1.8 1W Metal Ox 1.8 Ohm 1 W actual 2.2 ohm
RK59 220 RS2J Metal Ox 220 Ohm 2W
RK58 4.7 1W Metal Ox 4.7 Ohm 1W actual 4.7 ohm
RK63 150 RS2J Metal Ox 150 Ohm 2W
RK62 2.2 1W Metal Ox 2.2 Ohm 1W actual 2.7 ohm
RK51 220 RS2J Metal Ox 220 Ohm 2W
RK50 3.3 1W Metal Ox 2.7 Ohm 1W *listed as 3.3 ohm on schematic and 2.7 ohm on parts list for part number actual 3.3
RK55 150 RS2J Metal Ox 150 Ohm 2W
RK54 1.8 1W Metal Ox 1.8 Ohm 1W actual 2.2 ohm

RK38 = 47K (res-carbon flm 1/16w 47K-JB)
RK36 = 47K "
RK35 = 47K "
RK39 = 47K "
RK37 = 47K "
RK34 = 47K "

RK03 = 2.7K (res-carbon flm 1/16w 2.7K-JB)
RK02 = 2.7K "
RK01 = 2.7K "
RK04 = 2.7K "
RK06 = 2.7K "
RK05 = 2.7K "

RK40 3.3K (res-carbon flm 1/16w 3.3K-JB)
RK44 3.3K "
RK56 3.3K "
RK60 3.3K "
RK48 3.3K "
RK52 3.3K "

There are also numerous diodes in the circuit

Can anyone, (Leonard perhaps), point me to who has a kit for this Hitachi or point me to the best place to get the individual parts at this time. I also need to know which of these resistors to order and do the values need to be changed for the newer chips? None are discolored on the board but that does not mean they have not changed value with age or are possibly open. I will confirm the values with colors once I know which ones are the normal culprits to look at.

I'd yell help but it is 2:15 AM and already this weekend I have been unable to keep up with things that my other half has been breaking around here. Anyone who can help please feel free to chime right in. And if you know a really good tech in the Sacramento / Citrus Heights area 95610 I am open to that too [BarJo TV did not do house calls last time I checked and the TV is too big to haul around]. I have the tools but lack the time to do this properly which is to also check all the voltages and do a full manual convergence afterwards. I also understand the fluid sometimes needs to be changed (what is that about?) and I don't want to mess anything up that is salvageable. But if buying the parts is easier than finding a good tech we can try that first and maybe fix it soon.

I did locate a firm named Video Tech Service in Sacramento who did some work on it in '06. Unfortunately they have many complaints online since about fall of 2010 so I am a little spooked to call them for service if no one here gets back to me.

Thanks - Steve
 

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Your post has been moved to a more appropriate location to make information easier to find and to make it more likely that others who are interested will find your post.
 

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If you say that you lack the time to do the job properly, you are starting with a perspective that makes it much more likely that you will make the common mistakes that cause people to fail in similar repairs. Do it right, make the checks suggested, and align the set properly so that you don't waste your own time and money and that of people who might help you.

If you find links that are no longer current please let us know specifically what those are so that we can correct them.

You are lucky because these sets are among the easiest to repair for this problem and generally do not take a great deal of alignment. I have not seen issues with contaminated coolant in these models, but I also have not been doing such repairs for a couple of years. Don't assume problems until you check properly, and if the coolant is clear leave it alone.

You will need to check the resistors to verify the values. Do not rely on reading the color codes to determine replacement values. Typically the low ohm resistors (under 100 ohms) are the only ones that fail in these sets.

Do not rely on the companies that sell kits unless they are one of the suggested vendors, such as B&D. Even the best vendors may have run out of original chips and may need to source replacements. The recommended parts suppliers have good relations with their customers and track who the best suppliers are as well as try to get OEM parts when available. Before you buy, post the info about the vendor and what they are trying to sell you and we will check it out.

Since your problem is only in the green you can be pretty sure that your power supplies to the chips are intact. Just follow the sticky, replace the chips and any damaged or open resistors, then re-align the convergence. This should be as easy as these repairs get. Just don't run the set until it fails further. You will then have more troubleshooting and repair to do.
 

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Discussion Starter #4
Thank You Leonard. You indicate that typically those under 100 ohms are most vulnerable. I take this to mean that the six 1W resistors are the ones more commonly damaged. With an upgrade to the STK 392-150, do the values and wattage remain the same as to what the circuit was designed with originally?

Since I don't have a Hitachi kit number or access to Hitachi parts lists we will buy the parts individually as I could not locate a kit at B&D for the 51SWX20B. The manual lists the 57SWX20B, 65SWX20B also as a DP27 chassis and the 57TWX20B and 65TWX20B as DP27D models covered by the same manual and drawings in case your wisdom has any kits listed for those models. Thank you again.
 

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I do not believe that there was ever a kit for that chassis from Hitachi. The STK392-150 is an exact replacement for the -110 and requires no changes to resistors. Some of the kits for other chassis had mods to the resistor values and upgrades to the 394-160 IC in some cases.

There should be a version of the manual for your set which lists any differences from the base manual. I do not recall any differences in the convergence circuit in these models.
 

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Discussion Starter #7 (Edited)
Q. I am familiar with the older process way back aligning older TV's with a color dot bar generator. I usually use Magic Focus on this TV and let it align itself. I have used the manual convergence in the Magic Focus menu but generally it is no better than Magic Focus on this TV. In case a manual convergence process is needed on this TV I have the step by step manual and can follow it, however the first step in the process is "Receive a NTSC Signal." I thought analog NTSC signals went away in 2009. Lacking a NTSC color dot bar generator and not wanting to buy one, will a R-G-B component signal from a HD set top receiver substitute acceptably for the first step. The second step if launch magic focus.
 

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Discussion Starter #8
Q. I am familiar with the older process way back aligning older TV's with a color dot bar generator. I usually use Magic Focus on this TV and let it align itself. I have used the manual convergence in the Magic Focus menu but generally it is no better than Magic Focus on this TV. In case a manual convergence process is needed on this TV I have the step by step manual and can follow it, however the first step in the process is "Receive a NTSC Signal." I thought analog NTSC signals went away in 2009. Lacking a NTSC color dot bar generator and not wanting to buy one, will a R-G-B component signal from a HD set top receiver substitute acceptably for the first step. The second step is launch magic focus.

anyone? Leonard?
 

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The set generates the crosshatch pattern internally but you need s signal for it to sync to for each format to be stored in the convergence memory. Usually this is 480i and 1080i in CRT based sets bu some had additional native resolutions.

Magic focus type circuits are really just aligning to the last stored service level convergence data. That data may or may not be correct for the new parts after moving boards and wires around.
 

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Discussion Starter #10
so any source that has the different signals would work - say one for 480, one for 1080i one for 720P etc or am I just better off finding a used color dot bar generator with a NTSC signal on it?
 

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Any source. Just need one for each native resolution for the set to set up for each memory.
 

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Discussion Starter #12 (Edited)
Updated: Hitachi 51WX20B Convergence questions :) new chips installed

Thanks to Leonard it works again!!!!!!!!!!!

Those convergence chips sure get hot. In 10 minutes on they are too hot to touch for more than a few seconds. An infared gun showed 120F on the one closest to the back and 125F on the one closest to the front. But - the lines are back together and the color looks good. Interesting, one of the chips that came out was a STK392-150 and the other a STK392-110. This TV came new in a Hitachi box and all the wrappings from Hitachi. Some of the 1 watt resistors varied from the schematic values however all 1 watt and 2 watt tested at the color code on them individually, none had drifted and the board looked like none had ever been replaced. I updated the list at the beginning of this thread with actual values. Q: I looked up the Sanyo spec sheet and it shows the maximum stable temp on the stk392-1xx series as 125C, which is 257F. WOW! Would a computer fan help or is the 125F normal?

Also one fellow posted in another thread he could not figure how to get the high voltage leads out. I have the manual and it worked like the manual says - turn 90 degrees to unlock and remove, reverse going in. There are little fingers on the end that slide down in slots and then lock by turning 90 degrees. You can tell which way the cable wants to turn when you put them back. The red lead comes straight up.

I used a soldering iron and wick to remove the solder and a small tip iron to solder the pins then inspected each with a magnifying glass as my eyes aren't as good at 62 as they were at 22.

Cleaned the case and components with compressed air, cleaned the mirror and screen with sprayway and just a damp towel on the lenses until they were clean and compressed air. Did my best to do a general adjustment on it for gray scale and focus as well as width and height. Looks quite nice. Temps on the chip seem stable at about 120F - 125F with the cover off. All back together again - thank you again Leonard. Sent a small donation today to this forum. It really helped. Still curious about if the temps are normal.

I think fan holders like these may work to give extra cooling to those heat sinks. They are available from several sources including Skyline and E-bay - part. NEW Gateway E-2610N Air Duct for nBTX Case 8016335R (7825). Dell makes some too. Try your local computer 2nd hand store for ones like them.
 

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125 F is actually on the low side of typical for these chips. Extra cooling can't hurt, but careful alignment, including centering and minimal d.c. offset and minimizing the edge correction, along with proper heat installation results in a reliable repair IME. I rarely had a repeat service on these sets. Other brands and models that run hotter (150F is not uncommon, particularly in Samsung and Philips sets) might benefit more from fans but I never added them.

My philosophy was just to fix it right and I got good results.
 

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125 F is actually on the low side of typical for these chips. Extra cooling can't hurt, but careful alignment, including centering and minimal d.c. offset and minimizing the edge correction, along with proper heat installation results in a reliable repair IME. I rarely had a repeat service on these sets. Other brands and models that run hotter (150F is not uncommon, particularly in Samsung and Philips sets) might benefit more from fans but I never added them.

My philosophy was just to fix it right and I got good results.
 
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