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Toshiba 50HM67 Brightness Level Suddenly Changing   Goto page 1, 2  Next  
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Dr_Zoidberg56



Joined: 17 Dec 2008
Posts: 7

PostPosted: Wed Dec 17, 2008 1:59 pm    Post subject: Toshiba 50HM67 Brightness Level Suddenly Changing Reply with quote

Toshiba 50" Projection HD TV
Model 50HM67
Purchased 6/01/2007

About three days ago, I noticed that after the set has been turned on for about 20-30 minutes, the brightness level began to change. As I operate the set with the lamp in the low power mode, what was happening is different than the normal dimming that occurs just after the set is turned on. What would happen is that the picture would dim just a bit then brighten. It would do this several times, stabilize at the set brightness level for about 10-15 minutes and then repeat the process all over. Changing the preset brightness levels had no effect on this phenomenon. Yesterday, I began noticing that when the TV started this process, it appear to be noticeably darker than it had been the previous day and when it stabilized it was also noticeably darker.

I suspect that it may be time to purchase a new lamp, but what is happening doesn't fit the description of lamp failure in the owners manual. I called Toshiba and they said the same thing, suggested I take it to an authorized service center. Naturally, I don't have an extended warranty, so I really hate to pay for a service/diagnostic charge to find out it's something, namely replacing the lamp, that I can fix on my own. The problem has reached the level of annoyance that waiting to see if the lamp fails completely is not a pleasant option, given the Holiday period.

Is this just an atypical sign of impending lamp failure or something that merits a trip to the service center? Any assistance or direction would be greatly appreciated.
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Jesse Mack



Joined: 22 May 2008
Posts: 600
Location: The Last Frontier

PostPosted: Wed Dec 17, 2008 7:50 pm    Post subject: Reply with quote

"If" it has been 2 ~ 3 years or longer you probably have a least 4,000~6,000 hours on the set and your lamp has reached the end of its lifespan and needs to be changed anyway.

A Dimming/Dark picture IS a typical sign of lamp failure.

Hope this helps

Jesse
Dr_Zoidberg56



Joined: 17 Dec 2008
Posts: 7

PostPosted: Wed Dec 17, 2008 8:22 pm    Post subject: Reply with quote

Thank you Jesse for your quick response. While it has only been 1 1/2 years since we purchased the set, it does get a lot of use. My concern is that the changing brightness levels might be indicative of another problem, but a local repair shop told me that it is more likely a sign of impending lamp failure.

Again thanks for the advice.

Gerry
Dr_Zoidberg56



Joined: 17 Dec 2008
Posts: 7

PostPosted: Sun Dec 28, 2008 2:05 pm    Post subject: More Help/Advice Needed With Toshiba 50HM67 Reply with quote

I am now totally baffled! I ordered a new lamp from Advanced Lamps and naturally it arrived late in the afternoon on the 24th and I'm in California, so it was too late to call anyone if there were problems until Monday the 29th. I followed the removal instructions and found a considerable amount of dust around the lamp compartment and cooling fan. I used a computer vacuum attachment to gently clean out the dust (rather than blow it all around) and installed the new lamp without problems.

I turned the set on, and viola, a nice bright picture without any changes in brightness levels. However, the following morning when I turn the set on, I got no picture and the LED error code that the cooling fan was not operating. I followed the instructions in the manual, unplugged the set, waited a minute and plugged it back it. This time, I heard the fans come on. However, the picture would not come on. The yellow LED kept blinking and the set kept cycling on and off. I again unplugged it, waited about a minute and then plugged it back in. This time, the set powered up normally and the picture came on normally. After some time, I shut it off, turned it back on and it powered up as it is supposed to in the power saver mode, with the picture coming back on after several minutes.

The following day, when my daughter turned the set on, back to the red LEDs. I unplugged the set, opened the lamp door, removed and reseated the new lamp. After closing the door back up, the set worked just fine. This time I thought I would try the fast power mode and changed the setting.

This morning, the same thing all over again. This time, I removed the new lamp, reinstalled the old one, changed back to the power saver mode and the set is functioning just fine. The picture was maintaining a nice bright steady level through several prolonged off then on cycles but began the varying brightness levels problem again after several hours of use.

Given that the set is operating as it should with the old original lamp installed (despite possibly going through prolonged throes of failing), I have to assume there is some problem with the new one that is causing the start up failure. Before I call Advanced Lamps for a refund or replacement, has anyone experienced something like this or can offer an explanation? The other question is why the old lamp worked fine for several hours before exhibiting problems again or is it just taking its sweet time to fail completely?

I apologize for the convoluted story but do appreciate any advice as to how to proceed from this point.

Gerry
Jesse Mack



Joined: 22 May 2008
Posts: 600
Location: The Last Frontier

PostPosted: Mon Dec 29, 2008 6:09 pm    Post subject: Reply with quote

I looked on the Toshiba website and there are no issues like this listed.

That being said, I would do a visual on the power supply for expanded capacitors (domed tops). Unfortunately, the ballast is not available separately on this unit and is only available with the light engine.

A power supply that has bad capacitors can cause a multitude of symptomatic problems. (Low B+)

Hope this helps

Jesse
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Dr_Zoidberg56



Joined: 17 Dec 2008
Posts: 7

PostPosted: Mon Dec 29, 2008 8:08 pm    Post subject: Reply with quote

Jesse;

Appreciate the fast reply but what you said is way above my level of expertise. Other than the brightness issue, the set works just fine with the old lamp, in both the power saving and fast modes. Would it be logical to surmise that the new lamp has some sort of defect? If so, is it worth returning it for a replacement and try again. Or given my lack of electronic technical knowledge, just return the lamp for a refund and take the set into a repair shop?

Here I thought this was just going to be a simple lamp change. Thank you for your advice and help.

Gerry
Jesse Mack



Joined: 22 May 2008
Posts: 600
Location: The Last Frontier

PostPosted: Tue Dec 30, 2008 11:24 am    Post subject: Reply with quote

Since I do not know if the replacement lamp is indeed an exact replacement or not, your question of "defective new" cannot be answered with information available.

As to using the original lamp, Obviously your problem will return or you would not have ordered the new lamp in the first place. Usually brightness fluctuations are a power supply,ballast or lamp issue.

Hope this helps

Jesse
Dr_Zoidberg56



Joined: 17 Dec 2008
Posts: 7

PostPosted: Tue Dec 30, 2008 12:20 pm    Post subject: Reply with quote

Jesse;

The lamp & housing unit, while not Toshiba, are the correct part number/model replacement as listed for this unit (Y67-LMP).

From your response, it sounds as if I will have to take the set to a repair shop and arrange to return the lamp.

Thank you for all your advice on this problem.

Gerry
Jesse Mack



Joined: 22 May 2008
Posts: 600
Location: The Last Frontier

PostPosted: Tue Dec 30, 2008 12:55 pm    Post subject: Reply with quote

Actually, what I was trying to say is that I am not familier with your supplier and just because Model~Replacement identifications are correct it is necessary to say that unless you know for sure what the supplier is using as a replacement you cannot be sure that it is not a knock-off.

I am not trying to badmouth the supplier, I am just saying that there are generic lamps that may or may not perform as advertized.

Jesse
Dr_Zoidberg56



Joined: 17 Dec 2008
Posts: 7

PostPosted: Tue Dec 30, 2008 1:39 pm    Post subject: Reply with quote

Jesse,

Thanks. I considered that the replacement may not be as it should. As I used PayPal (who guarentee items sold through their services) for the purchase, I should not have a problem with the return.

Along these lines, could you recommend a reliable supplier that offers reasonable prices?

Again, I appreciate your help.

Gerry
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