20 Most Recent Hitachi 50SBX78B 50" Rear Projection Television Questions & Answers

hi you have faulty convergance ic also there may be some faulty resistor and capacitors that sit in front of the ic, thanks


Hitachi 50SBX78B... | Answered on Jun 27, 2017

Check for any air path obstructions and see if the fan is working, if not it needs replaced or checkd out. You can try and put a fan behind the unit to keep it cool this will sometimes work but the main reason is the set is getting to hot and it shuts itself down to protect itself from a failure.

Hitachi 50SBX78B... | Answered on Aug 14, 2011


See my tip at http://www.fixya.com/support/r4916941-diagnose_repair_projection_tv_high for help.

Thanks for using FixYa and for the great rating.


Hitachi 50SBX78B... | Answered on Jul 19, 2011

hi this is how are you going to do first try to unplug and then after a while plug it and power on the unit just to know what kind of error will be detected. now if you noticed when you turn on then it was a dead set or no power at all i may say it was power supply failure. another way is if their is a light indicator then is just an stand by no picture and no sound possible again is there are bad component at power supply as will as at the main board. now if you can do it with your own replace bad capacitor at power supply usually bulged to its casing which cause voltage drop. you can find parts replacement at www.digikey.com , replace with the same value then a panasonic brand capacitor much better. just give me response it still the problem not fix thanks for consulting us.

Hitachi 50SBX78B... | Answered on Jul 19, 2011

If only the standby light comes on, and the set does not turn on, it usually indicates a short in one of the protection circuits. To find out exactly what has gone bad, we are gonna have to perform component level testing. How good are your electronics/soldering skills?

Hitachi 50SBX78B... | Answered on Jan 30, 2011

This is a common problem on your model. You can get the repair parts and installation instructions from www.TvRepairKits.com - This one is a very easy DIY fix.

Hitachi 50SBX78B... | Answered on Jan 19, 2011

All projection TV sets have two very common problems. One is convergence ( 3D/Warped video) the other is CRT fluid ( Dull Video). Here are more details and solutions for both.

Common Problem #1) Convergence has gone out

Projection TV sets need to have all three colors - RED - BLUE - GREEN - lined up correctly on the screen in order for the video to look normal. When its out of alignment the video will look 3D, wavy, distorted, etc. Most of the time you just need to adjust your convergence in the TV menu. If you cannot adjust it in the menu - then your convergence is broken and needs to be repaired.

This is a very common failure on these projection sets and a fairly simple DIY fix. All projection sets including Samsung, RCA, Sony, Philip Magnavox, Panasonic, Pioneer, Akai, GE, JVC, Toshiba, and others at some point will have the same problem.

Common Symptoms include....

  • Screen looks 3D
  • Colors don't line up
  • One or more colors can't be adjusted when using the convergence menu.
  • Screen is bowed or warped.
  • TV shuts off after powering on. Power light will blink. TV may also make a chirping noise.
Here are some pics of convergence problems.



Common Problem #2) CRT Fluid is Cloudy

Projection TV tubes have a liquid coolant that is used to keep them from overheating. After many years the coolant in the blue and green tubes will become cloudy and cause the screen to look dull, red/orange, etc. You may even see halos around images.

Picture of a set that needs the fluid changed.

TV set after fluid change



You can see some more examples and find a fix using this link on Fixya http://www.fixya.com/support/r2861467-solution_video_looking_whiteish_dull

Hitachi 50SBX78B... | Answered on Jan 13, 2011

Unless the main board is checked the damage to the board cannot be accessed. so open out the set and check on for any failure of fuse or fusbile resistors that could have opened out with the water shorting.
If water is still found use a dryer to warm off the moisture.
It area of the water spill must be checked for the possible damage

Hitachi 50SBX78B... | Answered on Sep 15, 2010

Neither the fuse nor the cap are particularly special and can be purchased from any electronics supplier. I don't have the manual on this one, but the Cap value should be printed on the cap itself. Follow the link below to get to an authorized Hitachi parts supplier. Click on GUEST ACCOUNT and then US Dollars. At that point input the model number to get the listing of the available parts and part numbers. The parts will be listed by description.

The fuse is not specific to Hitachi either and the value should be stamped into the metal ends.

Hope this helps,


Link: http://www.encompassparts.com/shop_guest.asp

Hitachi 50SBX78B... | Answered on Apr 18, 2010

Ok, I know this set very well. There is one very common problem with it.

You need to locate 2 different parts---one is a fuse(does not look like a fuse---orange and almost dead center in the set---it will have a location number under it printed on the circuit board---location is E994 and it is a 2 amp pico fuse---you can check it just like any other fuse (it is soldered in).

With the set unplugged, if you check it and find it is open (bad) there is another part about 4 inches to the right of it you need to look at---

The problem this model has is a cap in the High voltage circuit goes bad---most of the time it will have a crack in its case or be burnt---Its location is to the right of the fuse and is C707-----it is near a transistor with location number Q777----there are a row of fairly large brown caps there with what looks like hot glue across the top of them--this cap is in front of the one closest to the front of the row of caps and it is so small you have a hard time seeing it---It is blue in color.

If you find the fuse open and or the cap damaged you need to replace both parts (less than 10 dollars)

If you find this is the case--let me know and I can give you part number/description for the cap---any 2 amp pico type fuse can be used to replace it.

You will have to unbolt the entire chassis and tilt it up so the bottom of the boards face the back of the set--each part only has 2 leads that need to be unsoldered and then resoldered when you replace the parts----if this is your problem--cheap fix and less than 20 minutes to do it. I have seen so many of these sets with this problem I carry the caps with me whenever I go on a house call.

Let me know what you find and if you need the part number description for the cap I can give it to you.

Regards, SD TECH

Hitachi 50SBX78B... | Answered on Feb 13, 2010


First try using Autofocus. If there is a convergence problem this won't fix the problem.

Try using the convergence alignment procedure from service manual.

Here the procedure that works on most Hitachi rear projection.

Here the grid with convergence problem


If the procedure does not work, then the two STK392-110 on convergence board must be replaced.

Before replacing the ICs you can test the pico fuses located on convergence boards. Simply read ohms to test if they have continuity.

Better also testing components on convergence board like resistors located at the base of STKs.

After removing the old STK, the new ones must be re-soldered using cooling paste.

Price for single IC can is about $8/$20. I think
STK392-110 on this model can be better replaced with STK392-150. I suggest contacting the seller on this.

The service manual is available here.

Hitachi 50SBX78B... | Answered on Jan 12, 2010

Yes, thats correct, when TV shows picture in separate colors or picture looks like 3D or double picture with different colors that means convergence section got failed and needs to be repaired.
Hope this info will help you.

Hitachi 50SBX78B... | Answered on Jan 12, 2010

Same problem. Replaced both convergence ICs about 5 months ago. Worked fince since then and just recently no sound, no video, blinking red on front panel and clicking sound. I suspect that the ICs went bad again and blew a resistor or two. I used cheap Chinese ICs instead of the Sanyo ones and thing this is why. I'll be looking at it again and post solution.

Hitachi 50SBX78B... | Answered on Jan 09, 2010

Ur power board is dead.need a new one.

Hitachi 50SBX78B... | Answered on Oct 31, 2009

may have several other fuses

Hitachi 50SBX78B... | Answered on Oct 11, 2009

E994= fuse, C707= .01uF/2kV.replace that fuse to fix the problem.this will help.
click the link directly and check out your model number in the list for more help.
replace C707 (blue cap) and the 2A pico fuse (E994). this will clkear the problem.

Please do rate the solution. Thank you for using fixya.keep updated. thanks.

Hitachi 50SBX78B... | Answered on Jul 17, 2009

the required blown parts are to be replaced and checked first.also check out the fuses are they near to end or got any burn marks on them. the parts are available at www,radioshack.com or at www.shopjimmy.com
thanks.please do rate.keep updated.

Hitachi 50SBX78B... | Answered on Jul 15, 2009

hi roby

the power supply is at fault in this matter. when you open the unit up
you will be able to spot a leaking or a molten "capacitor". once located, this capacitor is mounted on the power supply assembly. you may now have this assembly removed and replaced with a working PS.

this issue is considered the death diagnosis of most TVs.

hope this helps.



Hitachi 50SBX78B... | Answered on May 25, 2009

ok , on hitachi pro tv is very common with bad power supply u may want to replace the voltage regulator which is next to the fuse u already replace , also loose connection on all the power supply seccion , also u may want to check the resistor close by the convergence ic 2.2 ohn if this are smoke replace stk392-110

Hitachi 50SBX78B... | Answered on May 08, 2009

Your TV most likely has one or more possible problems.

Problem #1: Convergence Chip Failure ( common problem )

Here are some of the most common symptoms and example photos of a convergence problem
  • Screen looks 3D
  • Colors don't line up
  • One or more colors can't be adjusted when using the convergence menu.
  • Screen is bowed or warped.
Here is a quick test....

Using your original remote go-to the tv settings then goto the convergence section.

Try to adjust the red and then the blue convergence.

You should be able to move them up, down, left, and right.

If you can't move them in all directions your convergence chips are bad and should be replaced. This is a common problem.

2c07611.pngSolution #1

You need to replace the convergence chips and convergence resistors. Check the site www.TvRepairKits.com. They have put together a kits for most models. If you don't see a kit for your set send them a quick note and they will put one together for you. Their kits include a photo instruction guide, original OEM Sanyo STK chips, convergence resistors, pico fuses, etc.

Problem #2 CRT Fluid is Cloudy

Projection TV tubes have a liquid coolant that is used to keep them from overheating. After many years the coolant in the blue and green tubes will become cloudy and cause the screen to look dull, red/orange, etc. You may even see halos around images.

Picture of a set that needs the fluid changed.

TV set after fluid change


2c07611.pngSolution #2

What you will need to do is replace the coolant and clean the crt. You can get a repair kit from www.TvRepairKits.com that includes replacement coolant, photos. instructions, etc.

Hitachi 50SBX78B... | Answered on May 07, 2009

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