Question about Sylvania Televison & Video

2 Answers

I have a Sylvania LC370SS9 that will not power up. The standby led is on and I have 168v going to the video board. but nothing happens when I depress the power button. Please steer me in the right direction so I know which board to replace. Thanks Shawn

Posted by on

  • 4 more comments 
  • loggs Jan 01, 2011

    I'm not sure which transistors your asking me to check.
    I did check the base on Q638 1.78v IC637 3.3v and Q601 16.38vac.
    All measurement were taking in standby mode. I didn't get 5v on any of the
    rails.
    Thanks Shawn.

  • loggs Jan 01, 2011

    I have no video, sound or a power light.
    The only led lit is the standby led. There is no change when I
    Press the power button. Which ic should I check for the 5v output?

  • loggs Jan 01, 2011

    I do not know which transistor is the video output transistor.
    I do not have voltage on a 5v rail or 8-9v rail.

  • loggs Jan 01, 2011

    Anything labeled 5volts is reading nothing. I do
    have 3.3 volts on one spot going to the power on button.
    All the 9 volt rails read 0 as well.

  • loggs Jan 05, 2011

    I have replaced the power supply board and still the tv will not turn on.

  • loggs Jan 07, 2011

    ok I placed the power supply board and the tv still does not turn on.
    A friend of mine said it sounds like the tcon board is bad so I replaced that
    board too. Now the tv turns on but the left side of the screen is reversed.
    Do you have any ideas?
    Thanks shawn

×

Ad

2 Answers

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Sylvania Master
  • 6,993 Answers

Hello,

Your unit being stuck in standby mode is an indication that its having a power problem. Remove its plug from the wall and fix it back into the wall, then turn it on again. If its still stuck in standby mode, then the power supply board in the unit is the cause of the problem.

The power supply board might be defective and maybe that's why the unit won't power up. Its receiving power but it cannot transfer the current to the necessary part of the unit because a capacitor, diode, etc may have been faulty. Until these bad components are replaced, the unit might not come on.

This problem may have occurred as a result of irregular power supply, or excess power supply or power surge.

I do not think the defective power board needs replacement, rather some defective capacitors are causing this issue.
Open unit up and take a look at the power supply board.You will probably see one or more electrolytic filter capacitors that are bulged up in the top-not perfectly flat like the others.

The value of these capacitors will be different, most likely they will be somewhere around-820 to 2200uF/25 V( or /10V sometimes)

You can replace them with same values but I would recommend the voltage rating to be higher(like 35V for an original 25V) for reliability purposes.

What happens is,these bulged top capacitors will cause a low and unfiltered DC voltage=main board will malfunction(the relay will keep clicking until the caps are holding enough charge to bring the voltage up over a threshold point).

You can buy these capacitors at any Fry's or Radioshack store or you can order them online at vendors like "mcmelectronics.com"(look for electrolytic capacitors).
After replacing these capacitor(capacitors) most likely the normal operation will be restored.

Note: There may be also some other causes for this symptom ,like a defective T con board ,or main board,but the bulged top capacitors are the most common cause for this issue.

If you don't know about TV repairers, take the TV to the nearest repairman to fix the fault for you. Also, note that TV stores a lot of current, so wait a while before opening the TV back cover.

I hope this helps.

Good luck.

Posted on Jan 01, 2011

Ad
  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Top Expert:

    An expert who has finished #1 on the weekly Top 10 Fixya Experts Leaderboard.

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

  • Sylvania Master
  • 74,251 Answers

Hello
Have you measured the voltage at the base point of video output transistors at the base card. If not just measure it. It must be between 1.8 --2.8; changes according to video information. Check the collector voltage of the the video output transisotrs, or at the Green, Red and Blue cachode pin connections at the base card. It must be lower than the main input [168VDC]. If it is not so, or equal to that of the supply voltage, and there is no base voltages for the video output transistors, chroma IC is damaged, or it doesn't get proper voltage to function. If these are the conditions said above; there will be no raster and a blank screen will be the result.
Check the +5VDC rail and the other low voltage regulated supply rails 9VDC or 8VDC. If there is no voltage, check the relattive regulator ICs. Do the above said, and check whether it helps you or not. If not inform me through Fixya. I'm ready to assist you. OK.

Posted on Jan 01, 2011

  • 1 more comment 
  • The Knight
    The Knight Jan 01, 2011

    Hello Shawan
    I'm asking you to take the voltages at the collector and base of the video output transistors, which usually can be located at the basecard. As far as you have no screen, as you reports, the voltages at these points have to be measured. Collectro voltages of these transitors must be less than to its supply voltage, ie 168VDC. If there is no base voltage to this transistors, means there is no video output signal from the chroma IC. 5VDC, I reffered is the main system control voltage. You just measure the voltage across any one of the load resistor connected to the collector of any video output transistor fitted on the base card.
    Do this and inform me. I'm here ready to asist you. As you are aware in electronics, it is easy for us to communicate with each other. OK.

  • The Knight
    The Knight Jan 01, 2011

    Hello
    As there is standby LED, %V rail os Ok. Have you measured the voltage at the video output transitor I mentioned a few minutes ago? Chek it please. If there is no voltage, go to the main board again, and there will be a 8vDC regualted power supply rail, which supplies the voltage to video IF and other sections. Check it. Inform me. There is no schematic of your set available now in net. So we have to do it by checking voltages and other parameters.
    Do these and inform me. OK.

  • The Knight
    The Knight Jan 01, 2011

    Hello
    Video output transitor is that gives Red, Green and Blue colour outputs to the respective picture tube guns, and can be located at the pixcture tube base card, fitted at the neck of the picutre tube. On some sets it may be composed of a single IC or three seperate ICs for individual colour outputs. You just chek the voltage at the three colour cahodes. The voltage at these cathodes must be less than the main supply voltage you here reffered as 168VDC. It will come around 120VDC or so with video and should be. If not, these transistors are not functioning, and you have to go to the chroma section of your tv circuit. It seems that your TVs LOT [Line Output Transformer] is not functioning. The video voltage rail [168V} you refer comes from the SMPS power supply section, and from it we can make sure that the Power regulator section [SMPS] of your Tv is working properly. Now I thinks that you have got an idea. OK

×

Ad

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

RXV 871 not switching On


unplug for 10 minutes and try again. If not depress power button to get into set up mode and ck settings , if all else fails reset to factory defaults. P.S. "ck batteries in remote first"

Apr 21, 2014 | Yamaha RX-V871 - 7.1 Home Theater Receiver

1 Answer

I have a Sylvania lc370ss9 hdtv. When I turn the power on the set remains black, the power indicator flashes green and the power button will not shut it off.


The set has failed to come from standby to on fully---could be the power board but if it will not power off usually it is elsewhere.

Time to have a qualified shop take a look a get a estimate.

Dec 04, 2012 | Sylvania LC370SS9 LCD TV

1 Answer

Sylvania lc370ss9. tv just quit. no power at all when plugged in.(no sandby.nothing seems dead)checked cord and fuse both good. have done alot of searching. power feeds 2 boards. tuner board(i believe it...


Check and replace damaged component/s at its main power regulator [SMPS] section circuit. Contact any service technician. If you wish to get some details; check the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
It will be best to replace the power supply regulator board as card basis rather than making "Surgery" to it; which usually will make loss for both money and time. Even though you can make it right, it will cost around an amount equal to the cost of a new board; including the cost of (spare parts + service charge) More to say, most of the spare parts to it will be difficult to get from open electronic spare part market. This is true to most of the flat panel TV power supply boards; irrespective of its brand and screen size.
Search the site by type in the "brand name" to your device; in the "Search box at the top right of the display window of the Homepage" to get gathered related posts. ..

Apr 25, 2017 | Sylvania LC370SS9 LCD TV

1 Answer

Will not stay on goes back on to standby mode have tried unplugging it for an hour also using another outlet


You may have power supply or short circuits in the backlight inverter board which will cause the TV to go into safety shutdown mode, those are the two places you need to look first.
If you are going to DIY and have proper tools, electronics knowledge, and know safety precaution then please read on:

Please see my basic troubleshooting guide here:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide

Failed TV and Monitors: http://s807.photobucket.com/home/budm/allalbums

http://en.wikipedia.org/wiki/Capacitor_plague

Parts: www.shopjimmy.com
Capacitors kit: http://lcdalternatives.auctivacommerce.com/Default.aspx he can make you a set of caps.

Sep 06, 2010 | Sylvania LC370SS9 LCD TV

1 Answer

Lc370ss9 lcd tv turns off immediately after turned on


It may have shorted or failed power supply circuits, or shorted out the backlight inverter board, you will have to open it up and inspect the inside. It goes into shutdown to protect itself right now from further damage. Look at the power supply and the backlight inverter.
If you are going to DIY and have proper tools, electronics knowledge, and know safety precaution then please read on:

Please see my basic troubleshooting guide here:
http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide

http://s807.photobucket.com/home/budm/allalbums

http://en.wikipedia.org/wiki/Capacitor_plague

Parts: www.shopjimmy.com

Please post back what you find

Jul 20, 2010 | Sylvania LC370SS9 LCD TV

1 Answer

Sylvania lc370ss9 remote problem, comcast


you have to turn off the power save setting

Mar 01, 2009 | RCA RCR450 Remote Control

1 Answer

P35 Neo2 fails to power up


try to clear cmos here is the way if u dont know:
get to the jumper next to the mainboard try to change its position for 3 seconds then put it back to its normal position.
start the computer , enter setup and save defaults.

May 26, 2008 | MSI Computers & Internet

Not finding what you are looking for?
Televison & Video Logo

Related Topics:

693 people viewed this question

Ask a Question

Usually answered in minutes!

Top Sylvania Televison & Video Experts

The Knight
The Knight

Level 3 Expert

74251 Answers

matt martin
matt martin

Level 3 Expert

1210 Answers

Computer Repairing
Computer Repairing

Level 3 Expert

14641 Answers

Are you a Sylvania Televison and Video Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...