Comments on: Electronic Repair Questions/Answers and Testimonials- Part 27 https://jestineyong.com/electronic-repair-questionsanswers-and-testimonials-part-27/ Semiconductors, Test Equipments, Circuit Board Troubleshooting, Electronic Repair Courses and Many More! Mon, 27 Jul 2015 08:29:57 +0000 hourly 1 https://wordpress.org/?v=5.4.25 By: Jestine Yong https://jestineyong.com/electronic-repair-questionsanswers-and-testimonials-part-27/comment-page-1/#comment-219596 Tue, 15 Jul 2014 03:06:34 +0000 https://www.jestineyong.com/?p=1708#comment-219596 In reply to Ruwan.

Hi Ruwan,

Check the front panel switched and if all ok it seems that the data in the MCU IC could have been corrupted.

Jestine

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]]> By: Ruwan https://jestineyong.com/electronic-repair-questionsanswers-and-testimonials-part-27/comment-page-1/#comment-219577 Mon, 14 Jul 2014 15:44:38 +0000 https://www.jestineyong.com/?p=1708#comment-219577 Hi,

I'm having problem with Acer LCD monitor (Model AL1717) with TSUM16AL-LF. The problem started few days ago, by restarting the monitor after few minutes the monitor turned on. Some times it worked few minutes without problem, and starting to blink led and turning on and off itself.
I checked the power supply, it seems ok. LCD panel and back lights are ok as I tested. I think the problem probably be with the chip or the chip mounted board components. Now I cannot turn on the monitor anyway. No any LED is turning on, and power button not work at all.

I checked the voltage comes to board, is 5V. I tried giving separate 5V supply to board, but it does not turning on anymore with power button. Can you please point me in right direction to solve this?

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]]> By: admin https://jestineyong.com/electronic-repair-questionsanswers-and-testimonials-part-27/comment-page-1/#comment-6754 Thu, 09 Sep 2010 16:53:14 +0000 https://www.jestineyong.com/?p=1708#comment-6754 Hi Jeetu,

I have not seen any negative voltages in lcd monitor motherboard before. Do you have any diagram as i need to see this- thanks. In mother board RAM yes they need negative voltage but not on LCD Monitor.

Jestine

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]]> By: Jeetu Das https://jestineyong.com/electronic-repair-questionsanswers-and-testimonials-part-27/comment-page-1/#comment-6747 Thu, 09 Sep 2010 03:17:36 +0000 https://www.jestineyong.com/?p=1708#comment-6747 Hi !

I discovered a new this about this defective monitor scaler circuit where tsum15al-lf is used, the lvds signal to the panel are all in +ve volts, where as all the voltages should be in -ve, why this is happening can you please let me know.

Thanks in advance.

Jeetu

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]]> By: Jeetu Das https://jestineyong.com/electronic-repair-questionsanswers-and-testimonials-part-27/comment-page-1/#comment-6680 Sat, 04 Sep 2010 05:34:23 +0000 https://www.jestineyong.com/?p=1708#comment-6680 hi!
I have i done that, i have given a 5 volt directly to the drive circuit. which gives 12volt to the tl494. In off condition the panel becomes white or fully bright. but when given the vga signal the panel becomes dark again?

I am planning to make a isp circuit, let me try flash this ic. Thanks for your help and support.

Jeetu

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]]> By: admin https://jestineyong.com/electronic-repair-questionsanswers-and-testimonials-part-27/comment-page-1/#comment-6677 Fri, 03 Sep 2010 20:21:41 +0000 https://www.jestineyong.com/?p=1708#comment-6677 HI Jeetu,

I have not done this but you can try to drive it directly by bypassing the start circuit. That means the supply voltage of 12 to 14 volt (depends on model) will be directly connected to the vcc supply pin of inverter ic. This will cause a problem of white screen display because the lcd panel will always on.

If you have other question please do email me again.

Jestine

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]]> By: Jeetu Das https://jestineyong.com/electronic-repair-questionsanswers-and-testimonials-part-27/comment-page-1/#comment-6668 Fri, 03 Sep 2010 03:39:02 +0000 https://www.jestineyong.com/?p=1708#comment-6668 Hi!

Jeetu here again, i am stuck to this lcd monitor, i want to ask you a very imp thing, in the tsum16al-al-1 MCU ic, pin 86 is a pwm output of 4.9v to pwm ic tl494 to on the cfl. I have checked the good and bad board but the on drive voltage is there in both. Is there any method to drive the cfl directly.

One very basic question ?

when we increase brightness and contrast control what happens? does in both cases the cfl bightness increases and decreases.

Thank for your help and support.

Jeetu

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]]> By: admin https://jestineyong.com/electronic-repair-questionsanswers-and-testimonials-part-27/comment-page-1/#comment-6651 Wed, 01 Sep 2010 11:48:32 +0000 https://www.jestineyong.com/?p=1708#comment-6651 Hi Jeetu,

Sorry i do not have this service code because only manufacturer or the authorized service center have the way to enter it. Service code only can work if the lcd monitor is functioning normal. You may need to try different way to press on the front panel button plus power on to turn on the service mode. Without the right information, it will be hard to locate such way.

Jestine

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]]> By: Jeetu Das https://jestineyong.com/electronic-repair-questionsanswers-and-testimonials-part-27/comment-page-1/#comment-6650 Wed, 01 Sep 2010 06:47:36 +0000 https://www.jestineyong.com/?p=1708#comment-6650 Hi!

Can you tell me about the service codes of lcd monitors, i want to open the service mode of this monitor using tsum16al-lf-1 ic. can you please help.

Jeetu

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]]> By: admin https://jestineyong.com/electronic-repair-questionsanswers-and-testimonials-part-27/comment-page-1/#comment-6641 Tue, 31 Aug 2010 16:40:12 +0000 https://www.jestineyong.com/?p=1708#comment-6641 HI Jeetu,

In your case then the mainbaord MCU can be at fault because if it did not send an On signal to the inverter board the display will become dim. Check that the MCU have sinewave and all voltages are present in the mainbaord. A bad MCU can cause many weird problem like OSD locked will appeared, OSD intermittent comes and go off and etc. You need a programmer to reprogram the MCU but the problem is the MCU programmer is quite expensive.

Jestine

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