Repair Journal | Toshiba 39L1350U

Toshiba 39L1350U

Symptoms

TV just went black!

Repair

Replace main board

Explanation

It may be a symptom with just this particular model, but sometimes when a TV goes black, you are able to find the correct voltages when testing the PSU. However, the MAIN PCB may not be returning the correct voltage, and the set will not power on any longer. Replacing the MAIN PCB or EEPROM can fix issues such as this.

EEPROM (Electrically Erasable Programmable Read-Only Memory) | TV Basics

Alright, time for a small technical article.

Many of you TV Repair Enthusiasts are probably all like "what is an EEPROM?" Then, you Google it, and come up with "Electrically Erasable Programmable Read-Only Memory." Right. Makes sense. Not.

I get it. Everyone has struggled through learning technical mumbo-jumbo. Herein I make an attempt to explain EEPROM (insofar as TV's are concerned) in layman's terms.

What is EEPROM?

Look at a motherboard (main PCB) from a television. You'll be able to locate an 8-pin IC somewhere on the board, usually smaller than your fingernail. Tiny! But yes, it's there. That little IC stores information such as operating frequencies, settings, etc. 

The cool thing about this whole shebang is that the EEPROM does not lose data when there is no power. This is why you can set all of your picture settings on your monitor or TV, power it down, unplug it and move it to a new location and still retain all of the settings when you power it up again. Neat! 

The IC on your motherboard was programmed with the factory settings when it was manufactured.

How do I know my EEPROM has been corrupted?

While it's kind of rare, sometimes EEPROM data becomes corrupted when static discharge or high voltage spikes occur. It can seem like your TV is completely dead because it won't power on. Perhaps you cannot change settings such as brightness, contrast, audio settings, etc. Or maybe you can change them, but they simply will not save. Another thing that can happen is your TV will run for a moment and shut down unexpectedly or run for awhile and then randomly turn itself off. These are all very puzzling symptoms, but can all be associated with corrupted EEPROM data.

What can be done?

Nothing can be done without a programmer, that is, assuming you do not wish to purchase a new IC. Often times, if this is a common problem with your television, sellers will have pre-programmed EEPROM's available. If this is the case, you can simply replace the EEPROM (assuming you are confident enough to solder SMD's*).

Otherwise, if you're tech savvy, you may wish to purchase an EEPROM programmer and try to find a source for the factory data. Either way, you can get your TV working good as new and for under $20.00 in most cases.

*Surface Mount Devices

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Thanks for reading, and if you have questions, you may post them in the comments as always!

-Craig

Repair Journal | LG 26LC7DC | Won't turn on!

LG 26LC7DC | 26" LCD

Symptoms:
TV had trouble turning on. Over the following weeks, it would take longer and longer to power up. Finally, it would not power up at all, and only the power LED would blink (green/red) when the power button was pushed.

Diagnosis:
Because this particular set had power issues that worsened over time, my first thought was capacitors. It's like when the batteries start to get low in your drill or what have you. Opening the set up showed that this was, indeed, the case.

Solution:
Replace the capacitors! This reminds me that I need to do a video tutorial on this (or at the very least, find a good one on YouTube).

Anyway, if you are comfortable with a soldering iron, this will be a quick job for you! In my case, the power supply had five (5) busted caps including the following: 1x 3300uF 10V, 1x 2200uF 10V, 3x 680uF 35V.

After carefully replacing each with a comparable part, The TV worked great! My parts list included: 1x 3300uF 16V, 1x 2200uF 16V, 3x 680uF 35V.

Good luck, and if you find that you have a query, please get a hold of me at crkalinowski@gmail.com.

Repair Journal | Samsung PN43D450A2FXZA (N102)

Samsung PN43D450A2FXZA (N102) | 43" PDP

Symptoms:
TV will not turn on. Relay clicks repeatedly on power-up attempts.

Diagnostics:
Test critical voltages.

Panel sticker rated voltages:
VS: 205V
VA: 58V
Vsc: -180V

With everything hooked up:
VS: 0.3V-0.5V
VA: 0V
Vsc: -- (not measured)

Remove power connector (X and Y-MAIN):
VS: 205V (spike and shutdown)
VA: 55V (spike and shutdown)
Vsc: -- (not measured)

-NOTE- 
The reason the voltage spikes and disappears quickly is because the circuit is not complete (i.e. the boards needed for operation are disconnected from the power circuit) and the TV goes into shutdown immediately. When you plug in the power cord with these boards disconnected, you can have your DMM probes on the VS and VA test points beforehand. This allows you to see if the PSU is operating correctly. Seeing the correct voltages at startup confirms that the short is elsewhere.

Continuity tests (power off, X and Y-MAIN disconnected)
Set your DMM to continuity mode and place one probe on the chassis and another at each of the following test points. If there is continuity (i.e. there is a tone that sounds when my DMM detects a complete circuit), you have a short at the tested point.

VS: OK
VA: OK
Vsc: OK
XS_E: SHORT
XS_C: SHORT
XG_E: SHORT
XG_C: SHORT

The short on the X-MAIN board indicates that this is the problem board.

Solution:
Replace the X-MAIN board. It is most certainly bad. While you're at it, get a hold of a LOGIC BOARD (the green one just south of the PSU) and replace it as well. Don't ask me why, but this vintage of 43" Samsung Plasma (the "D" in the model number "PNxxDxxx" indicates it was manufactured in 2011) seems to be a victim of this failure often. If you have a shorted X-MAIN, there is a 70-80% chance that the LOGIC is also shot.

Be sure that you immediately upgrade the firmware on this television after installing the new LOGIC and X-MAIN boards.

-PROTIP- Now, if you were working with a "PN51Dxxx" (the 51" plasma model from this year), it is more often the Y-MAIN and X-MAIN. You would get a short on the Vsc point during continuity testing if the Y-MAIN was bad. 

Pictures will be available soon!

Repair Journal | Toshiba 32SL400U

Toshiba 32SL400U | 32" LED LCD

SYMPTOMS: TV fully functional, with the exception of the speaker(s) making a "clicking" sound. Audio comes through periodically.

DIAGNOSTICS: Opened set for inspection. When powered on, clicking continued. When speakers were removed from their mount points, the clicking stopped. A simple "touch-test" (i.e. making contact between the speaker terminal and the panel assembly) showed that the source of the clicking was essentially a short between the aforementioned components.

SOLUTION: Bend speaker terminals up and away from panel slightly and use electrical tape to insulate area behind speakers.

Screw and speaker locations.

Instructions. You must remove all back cover screws (don't forget the one near the inputs) and base stand screws. Once you've accomplished this, carefully pry up the back cover, and thread the cord through the hole in the back. With the cover removed, inspect the speaker assemblies. If you wish, turn the set on with an input connected so you can test the audio. If you can fiddle with the speakers and recreate the clicking sounds, you've nailed your problem. Move the speaker assemblies out of the way and place a strip of electrical tape on the panel assembly (you can see the red tape through the slots in the picture) and bend the terminals (gently) in the direction away from the panel assembly before reinstalling. Carefully reassemble the set and enjoy! You've just fixed your audio for free.