20 Most Recent Toshiba 55H70 55" Rear Projection Television - Page 7 Questions & Answers

The deflection board in failing, eventually it will not come on at all, disconnecting power is only reseting the HV shutdown protection circuit which is the reason your set if failing. Have a technician replace the Horizonal Output Transistor and the flyback transformer.

Please comment if you need futher assitance.
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Your symptom sounds like a damaged convergence IC.

There are two and large IC’s that control the convergence in a big screen set. They are secured to a very large aluminum heat sink. They will have a part number stamped on them that will start with an STKXXX-XXX, like STK392-110, and they are located on the signal board (on the left as you look into the back of the set).

Along with the convergence IC’s there will also be some associated components that will need to be replaced as well. There are some resistors that are part of the convergence circuit that will be open and need to be replaced. Most likely these will appear charred in the center. If you have an Ohm Meter or a DVM, check all the resistors that are close to the IC’s and you should be looking for either ones that have opened or have changed values.
There are also two resistors on the front of the board located in the middle that are fusible link resistors, these should be checked for opens and replaced if they are found so.

I would suggest that you contact a service center in your area for a complete diagnosis and repair, as this type of repair can get a little tricky. But if you want to repair the set yourself, just remember to be careful. The capacitors and CRT’s can hold a charge and may shock you.


If one of the convergence IC’s are found to be bad, I would replace them both, if one has gone bad the other may go soon. I usually order my parts from Andrews Electronics in California, they will have the OEM components that you will need.
Their site is http://www.andrewselectronics.com/welcome.aspx
And their phone number is a 24-Hour Order Desk: (800) 274-4666
I recommend the phone order so you can talk to the person about the different types of IC’s that are available.

I would also advise that the convergence IC’s be OEM or better, just because they are cheap does not mean that they are a good deal. I have seen the cheap IC’s fail after a short time, even though they look exactly like the OEM IC’s. I think that the bottom line is that you will get what you pay for when it comes to the parts.

You can also try http://www.tvrepairkits.com/ , I have not tried them yet, but they do carry OEM or better parts.

I hope this information allows you to resolve this issue.

The lamp is probably burned out. They go after several years. You would most likely need to purchase and install another lamp(s)

It is possible that the bulb might be going out. if this is a DLP television the bulbs are usually oinly good for 2 to 3 years depending on how much teleivision you watch. You can buy them online or from the store you purchased the telivision from. They are loacted at the back of the tv and can be changed using a screwdriver. They usually cost between $130 to $200 dollars depending on bulb make and where you buy it.

Probable power supply failure but could be a failed lamp preventing the powering up of the set. If there seems to be a pattern to the blinking activity, record this so when in contact with the mfr. you can ask if this indicates a lamp failure or as below.

The supply is normally built on a separate board since these are often out-sourced by set manufacturers.

Unplug your set overnight to allow potentially hazardous voltages to discharge, remove the back panel of the set so you can see the guts.
Look for a smaller board with larger parts on it; some cylindrical (capacitors), others block-like and relatively large (chokes and transformers).
You should also see a relationship between the board and the incoming AC.
Check the board for a label or if not present, a stamped-on number.
Call the manufacturer's service center with your TV model number and the number found on that board and inquire about repair/replacement costs; if both are offered, they won't be that much different.
If you must buy a new board, don't dispose of the failed one as there are smaller companies that can repair it for less than the mfr. and then keep it as a spare as this problem will likely arise again.

try this program

combofix (google it)

This is one of the sets with bad HYPER boards. If it clears up after a while this is your trouble;I just checked a site in LA--the only way to get the board is to go to PTS electronics and send them the original board for repair--part alone is over 200 and is soldered in--a lot of these sets are having this problem.

I know I am not giving you good news but I am pretty sure this is what is wrong with your set--seen dozens of them.

if you think I helped you in some way--give me a vote here I do this for free. IF YOU HAVE QUESTIONS OR NEED MORE HELP contact me by responding to this post.

SD TECH (SAN DIEGO)

First thing to try on toshiba RPTV's is to disconnect the 3 connectors by the conv. IC's. If the ic's are shorted the tv will run with them disconnected but obviously without convergence. If it still doesnt run, i would start with the vertical section as this series has had some issues.

If this is a 55H70 it uses two STK-392-110 convergence IC's---both need to be replaced and the protection resistors (called feedback) need to be checked---they are checked with a meter just like a fuse----if one of them is open(bad) one of the two Convergence chips got it.

This repair can usually be done right in your home----some sets take more time and are harder to do then others but usually the whole job takes about a hour----I have done hundreds of these repairs in the last year.

You can buy the STK's on ebay for about 12 for a pair plus shipping----total parts cost should be under 20 dollars.

I do this here for free so if this has been helpful give me a vote here. if you have questions or need help:

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Replace Both of your STK ICs big black ICs will have P/N on them STK392-110 for parts to order call Mats 1-800-628-1118

Ballast is connect to other side of Lamp,Have you replaced lamp yet?

Check out the pico fuses. You cannot tell are bad by looking at them. Are you getting + and - supplies to the convergence ICs? Also check whether the 1.8ohm resistors are still OK. They are prone to getting burnt. Checking for dry solder joints will also help especially if tv set has been transported but this needs patience.

Most common failure is the convergence ICs, they are soldered in and would require a qualified technician installation, cost about $300-$400
if you want to attempt this repair some troubleshooting is needed first.
there are a few fuses that need to be checked, usually 5amp soldered in tiny black looking things. If one is open you can replace it and then unplug all three convergence yokes (wires come from the yoke around each CRT to the smaller plugs near the ICs) . If you get a picture that looks wavy and colored you will need to replace the convergence ICs (and the fuse you already installed). the (2) ICs are usually stk392-110
hope this helps
Eric I’m happy to help further over the phone at https://www.6ya.com/expert/eric_ab7c09ec01841771

call up the menu and look to see if words have red or 3d effect---if this is so, suspect you have a convergence problem; the set should also have a option for adjusting the convergence---some just give you a cross in the middle of the screen---if red or blue will not adjust either up/down--left/right you have a bad convergence IC----The Hitachi sets all use two IC's and Usually this repair can be done in your home----I do a lot of them here in the San Diego area where I live----have done over a hundred in the last year on all brands of sets. If you know someone who knows how to solder etc, you can (get me model number) buy both the convergence IC's on Ebay for under 15 dollars plus shipping; some internet places offer a kit with the IC and whatever other parts might be needed; usually this is a waste as most of the time only the IC's and maybe one or two resistors around them are gone.

If you need more direct help my email is: [email protected]

I do this here for free so if I have helped you give me a vote here.

it is hd ready you just need bluray player/hd cable box as long as its from a hd source or upconverting dvd player you will need component cable red blue green.let me know if you need more info.

projection sets on occation need to be re-alligned. check your owners manual if you have one and re-align your lamps to the test screen that is displayed when you press 'menu' from your remote or from the front of the tv. This should fix alot of it and you may find the color adjustments may need adjusting after re-aligning your lamps. hope this helps. I had one and that sounds like the 'ghost' images I had till I did this.

it means that tv having low supply voltage. check the secondary power supply along SMPS.

pls check all cables if installed properly

alright this would be due to the convergence board they have intergraded circuits that are built onto the board they are called STK IC's if those are replaced you then can line up your screen this is called skewing.

1. change the STK IC's
2. Check for any fuses blown on main power unit.

I hope this information find you success on you do it yourslef repair if you do not know what the above mentioned parts are then I would advise you to take it in or have someone come to you.

Thanks for using fixya.com
Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/edwy_1a56970cf1ea4620

It looks like you might have a defective ballast, you can identify it by the clicking sounds it's making, also since the ballast is the one in charge of providing energy to the lamp so it can light up the whole screen, if it's not working. there will be no image... there are cases like yours, where the audio is also involved.