Thursday, October 27, 2011

Samsung 50-Inch 1080p DLP HDTV Review

!±8± Samsung 50-Inch 1080p DLP HDTV Review

Are you thinking of buying a Samsung 50-inch 1080p DLP HDTV?

This is a popular DLP HDTV model, and is a bestseller in many different shops. It has been around for just over half-a-year, and the customer base and comments has grown enough that we can now get a good feel for its pros and cons. I've consolidated a number of customer reviews from around the net. Overall opinion is that HDTV model is good and cheap, but not perfect.

Here is a useful rule of thumb: If you want to buy a HDTV, find out the watching distance in feet and multiply that with 5. That's the size of the screen you need. For example, if your watching distance is 10 feet, 10 times 5 is 50. So choose a 50-inch TV.

Good Points

Even when Samsung 50-inch 1080p DLP HDTV first came into the market, it was one of the cheaper 50-inch HDTVs. Now that the model is half-a-year old, it is even cheaper if you buy it from online retailers like Amazon. You are likely to see about 0 of savings off the list price. You also save on certain taxes and shipping costs. Additionally, if you find that the price has dropped between the time you bought the TV and the time you received it, you can ask the retailer to refund the difference. Reputable companies like Amazon actually honor such requests.

Although electronics tend to become obsolete quickly, this HDTV was leading edge when it came out. It already had 1080p resolution - many broadcasters are still catching up to this latest standard. Even now, its technology is quite advanced, and will likely remain so for the next few years.

Samsung 50-inch 1080p DLP HDTV uses an advanced technology called LED light engine. What it means for you is that the pictures are clear and detailed, and the colors look natural and true. Movement and action is much better rendered compared to normal LCD technology, and you won't see blurring or loss of detail. This HDTV also does well in bright rooms with considerable daylight penetration.

The built-in 2-speaker surround sound is of good quality. Do make sure the surround sound mode is turned on. HD broadcasts received over a simple, cheap, indoor antenna look great. Other content (Regular DVDs, SD/HD broadcasts, Nintendo Wii, DVD, Xbox 360, etc.) also look fantastic.

You probably already know its dimensions: 45.2"(W) x 31.8"(H) x 13.4"(D) 61.3 Lbs. This 50-inch DLP HDTV is thinner than many of its competitors, and is light enough for 2 persons to move around.

There are abundant connection inputs for HDMI, S-video, RGB component, digital, optical and analog sound, and RCA jacks, and they are located on the right side of the set for convenient access - this makes it easy to hook up. Unfortunately, this can be an issue if you place your TV in a cabinet.

Samsung 50-inch DLP HDTV is pretty user-friendly. The user manual is good and extensive (although not written for novices). The remote is intuitive and the menu system is straightforward. Note that it may not have as many functions as more expensive systems.

Its pretty quiet, since it uses LED light sources instead of the more normal bulb and color wheel of most other DLPs. Since the LED engine is cooler and more energy-efficient than the bulb and color wheel, Samsung 50-inch DLP HDTV also doesn't need a powerful cooling fan. Overall, you get good energy savings - it is Energy Star rated. Another good point is that the LED lasts longer than the bulb of normal DLPs (which need to be changed every 2 or 3 years).

Some of you might be nervous about getting faulty goods by buying from online retailers. The big and reputable companies like Amazon usually have a 30-day guarantee period. When any problems crop up, they have a good reputation of honoring their commitments to replace or refund the TV. If you are not certain about your online retailer, you can check their reputation with the Better Business Bureau.

Problems Encountered By Customers

Buying this DLP HDTV is not perfect, though. Customers have reported 3 main kinds of problems.

1) Delivery & Service Problems:

a) Some customers complain about not receiving their TVs. This is more likely to happen with online retailers with their more complex supply chain and delivery procedures - either their orders were not received by the vendor supplying the TV to the online retailer, or the delivery agent did not receive the correct delivery from the vendor, etc. There are precautions you can take to minimize problems (see the section below).

b) Sometimes you get an incompetent or lazy deliveryman. He may not be able to find the place you live. Or he may not want to deliver to your doorstep. Or he may just drop your TV off at your doorstep and refuse to carry it in for you. On the other hand, there are also stories of deliverymen who go beyond the call of duty - they help you to move your old TV to its new location, then they bring your new Samsung 50-inch 1080p DLP HDTV in and install it for you. Then the even take away the packing crate for you. Sometimes they do it for free, sometimes you have to pay them a few bucks extra.

c) There are also some complaints of poor customer service from Samsung. It is typical of any large company's service - when you get a good Customer Representative, you get good service. It helps if you get their name ahead of time before you start telling them about your problems or asking them questions. If you get a jerk, you get lousy service. Don't get mad, get their name, and escalate to their boss. If that doesn't work, get a refund or replacement from your retailer.

2) Quality Control Problems affecting some individual TVs:

a) The dreaded "blue-halo" effect, which basically is a blue-ish area of light that becomes visible in dark areas of high-contrast scenes, around the lower center of the screen. This seems to be caused by a ring around the lens of the projector that should be black, but is reflective silver in some TVs.

b) There is a "hot" or bright spot in the middle of the screen and the center is a little brighter than the edges.

c) When the entire screen is one color, sometimes the four corners of the TV fade in brightness.

d) The image is skewed (left side lower than the right), there is a noticeable green tint that is not correctable via any of the user settings.

e) Picture shuts off for minutes or hours at a time - which can be a motherboard problem.

f) Spots on the screen - which can be an unfixable LED light engine problem.

If the problem crops up well within the online retailer's guarantee period (typically 1 month), then call Samsung customer service and they will send a technician in about 2 working days to fix the problem. Otherwise, make good use of your retailer's guarantee period to get a replacement. Reputable online retailers like Amazon are pretty good about honoring their guarantees without hassling their customers.

3) Problems with the model or DLP HDTV technology which affect all TVs:

a) SD images via digital cable (connected via HDMI) are sometimes a little pixellated.

b) Small amount of curvature on horizontal lines right at the top of the set (which is a common artifact with this type of set) - not generally noticeable.

c) Minor incompatibility with 480p resolution settings and DirecTV (call your DirecTV customer service to get some satellite technicians to figure this out)

d) Echo if you have both TV speakers & surround sound speakers on and the volume is high. Just mute the TV, or use 5.1 or 7.1 surround sound.

e) When viewing non-HD programming in 4:3 mode there are a set of double lines at the edge of the image. This may be too distracting for some people.

f) When playing a letterbox or widescreen DVD the 16:9 or Zoom settings are a little off. The center of the image at the top is nearly 3/4 inches lower than at the ends creating a slight "U" shape or concave appearance. This can also be very distracting for some people.

g) Slight geometry problems (noticeable bowing towards the top center portion of the screen)

h) On non-stretch mode with SD (where you have a black bar down each side of the picture), the sides of the image are bowed in a little bit.

i) Viewing angle is limited, which sucks if you have a large number of people gathered around it. Just make sure that you're in the center and can see the screen. The viewing angle is good to about 140 degrees, although it is best up to 90 degrees. Still, this is supposed to be the normal level of performance for DLPs. Basically, the best seat is the sofa in front of the TV, although anyone on the love seat has just as good a picture.

Precautions To Take

1) If you buy from an online retailer like Amazon, make sure the TV is sold directly by Amazon. Amazon sometimes acts like a storefront for other companies. This means that you are the other company's customer, not Amazon's. How can you tell? Look for this sentence on the 1st page after Amazon lists the "Price" of the TV - "Availability: In Stock. Ships from and sold by Amazon.com." Other online retailers should have something similar.

2) Print the receipt. Although this is common sense, sometimes we forget. Or something else happens, for example, your printer breaks down. If this happens, just take a screen capture and save the picture to Microsoft Word.

3) Remember: You are probably buying online to take advantage of lower costs and free shipping. Don't expect 5-star service. Take the initiative to find out the contact of the actual supplier and delivery agent so that you can keep track of your order and delivery. Call the online retailer's customer support if you have any doubts.

4) If you think there is a problem with your Samsung 50-inch 1080p DLP HDTV, take advantage of the 30-day guarantee period to get a replacement or refund. Don't suffer problems for 3 months before complaining. By this time, it is too late.


Samsung 50-Inch 1080p DLP HDTV Review

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Monday, October 24, 2011

Testing Flyback Transformer - How to Test and When to Replace It

!±8± Testing Flyback Transformer - How to Test and When to Replace It

Nowadays, more and more monitor comes in with flyback transformers problems. Testing flyback transformers are not difficult if you carefully follow the instruction. In many cases, the flyback transformer can become short circuit after using not more than 2 years. This is partly due to bad design and low quality materials used during manufactures flyback transformer. The question is what kind of problems can be found in a flyback transformer and how to test and when to replace it. Here is an explanation that will help you to identify many flyback transformer problems.

There are nine common problems can be found in a flyback transformer:

a) A shorted turned in the primary winding.

b) An open or shorted internal capacitor in secondary section.

c) Flyback Transformer becomes bulged or cracked.

d) External arcing to ground.

e) Internal arcing between windings.

f) Shorted internal high voltage diode in secondary winding.

g) Breakdown in focus / screen voltage divider causing blur display.

h) Flyback Transformer breakdown at full operating voltage (breakdown when under load).

i) Short circuit between primary and secondary winding.

Testing flyback transformer will be base on (a) and (b) since problem (c) is visible while problem (d) and (e) can be detected by hearing the arcing sound generated by the flyback transformer. Problem (f) can be checked with multimeter set to the highest range measured from anode to ABL pin while (g) can be solved by adding a new monitor blur buster (For 14' & 15' monitor only.) Problem (h) can only be tested by substituting a known good similar Flyback Transformer. Different monitor have different type of flyback transformer design. Problem (i) can be checked using an ohm meter measuring between primary and secondary winding. A shorted turned or open in secondary winding is very uncommon.

What type of symptoms will appear if there is a shorted turned in primary winding?

a) No display (No high voltage).

b) Power blink.

c) B+ voltage drop.

d) Horizontal output transistor will get very hot and later become shorted.

e) Along B+ line components will spoilt. Example:- secondary diode UF5404 and B+ FET IRF630.

f) Sometimes it will cause the power section to blow.

What type of symptoms will appear if a capacitor is open or shorted in a flyback transformer?

Capacitor shorted

a. No display (No high voltage).

b. B+ voltage drop.

c. Secondary diode (UF5404) will burned or shorted.

d. Horizontal output transistor will get shorted.

e. Power blink.

f. Sometimes power section will blow, for example: Raffles 15 inch monitor.

g. Power section shut down for example: Compaq V55, Samtron 4bi monitor.

h. Sometimes the automatic brightness limiter (ABL) circuitry components will get burned.

This circuit is usually located beside the flyback transformer. For example: LG520si

Capacitor open

a. High voltage shut down.

b. Monitor will have 'tic - tic' sound. Sometimes the capacitor may measure O.K. but break down when under full operating voltage.

c. Horizontal output transistor will blow in a few hours or days after you have replaced it.

d. Sometimes it will cause intermittent "no display".

e. Distorted display i.e., the display will go in and out.

f. It will cause horizontal output transistor to become shorted and blow the power section.

How to check if a primary winding is good or bad in a Flyback Transformer?

a) By using a flyback/LOPT tester, this instrument identifies faults in primary winding by doing a 'ring' test.

b) It can test the winding even with only one shorted turned.

c) This meter is handy and easy to use.

d) Just simply connect the probe to primary winding.

e) The readout is a clear 'bar graph' display which show you if the flyback transformer primary winding is good or shorted.

f) The LOPT Tester also can be used to check the CRT YOKE coil, B+ coil and switch mode power transformer winding.

NOTE: Measuring the resistance winding of a flyback transformer, yoke coil, B+ coil and SMPS winding using a multimeter can MISLEAD a technician into believing that a shorted winding is good. This can waste his precious time and time is money.

How to diagnose if the internal capacitor is open or shorted? By using a normal analog multimeter and a digital capacitance meter. A good capacitor have the range from 1.5 nanofarad to 3 nanofarad.*

1) First set your multimeter to X10K range.

2) Place your probe to anode and cold ground.

3) You must remove the anode cap in order to get a precise reading.

4) Cold ground means the monitor chassis ground.

5) If the needle of the multimeter shows a low ohms reading, this mean the internal capacitor is shorted.

6) If the needle does not move at all, this doesn't mean that the capacitor is O.K.

7) You have to confirm this by using a digital capacitance meter which you can easily get one from local distributor.

8) If the reading from the digital capacitance meter shows 2.7nf, this mean the capacitor is within range (O.K.).

9) And if the reading showed 0.3nf, this mean the capacitor is open.

10) You have three options if the capacitor is open or shorted.

- Install a new flyback transformer or

- Send the flyback transformer for refurbishing or

- Send the monitor back to customers after spending many hours and much effort on it.

* However certain monitors may have the value of 4.5nf, 6nf and 7.2nf. Note: Sometimes the internal capacitor pin is connected to circuits (feedback) instead of ground.

Tv rca flyback transformer circuits usually do not have a internal capacitor in it.

If you have a flyback diagram and circuits which you can get it from the net, that would be an advantage to easily understand how to check them.


Testing Flyback Transformer - How to Test and When to Replace It

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