Comments on: Repaired BenQ FP93V 19″ LCD Monitor

By: Mithun Kumar

Mithun Kumar — Thu, 24 Jun 2021 13:06:55 +0000

1200ap40 is not available please suggest me with other

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By: buddhika

buddhika — Sun, 06 Dec 2020 21:03:35 +0000

In reply to sapto (Indonesia).

Thank you. I have 2005 led monitor

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By: ahmad

ahmad — Thu, 15 Feb 2018 15:11:48 +0000

hi! Acer AC711 crt monitor that came dead to me i have checked it and found that one power mosfet p7nk80zfp, and tl3842 oscillator ic were shorted i replaced p7nk80zfp with k2645 and the oscillator with same part number i test it with series bulb. the bulb goes on and off. then i power it on for a few seconds the led glows with orange color. i thought all is well and i packed it again. after putting back the screws i tested it in series again the bulb glows bright without flicking i opened it again and found that this time only the k2645 was shorted again. plz guide me where is the problem

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By: Jestine Yong

Jestine Yong — Wed, 04 Feb 2015 08:44:54 +0000

In reply to Markuz Zericci.

HI Markuz,

Sorry I do not have the Monitor or schematic with me thus I do not have the reference. This this Monitor was repaired back 2008.

Jestine

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By: Markuz Zericci

Markuz Zericci — Tue, 03 Feb 2015 16:15:53 +0000

I have replaced these parts, but alas, the powerboard is still dead.

I was wondering if i could swap out the powerboard for another i have on hand, but i can't seem to find the pinouts for this board.

Do you happen to know what the pinouts are for the black connector that has 10 pins (connector from inverter to graphics driver board)

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By: admin

admin — Thu, 20 Nov 2014 06:09:31 +0000

In reply to Tarsem Bhardwaj.

The equivalent part number is at the 3rd photo

Jestine

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By: Tarsem Bhardwaj

Tarsem Bhardwaj — Wed, 19 Nov 2014 12:19:56 +0000

Power FET P7NK80ZFP is not available. Pl. suggest the alternate FET

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By: Jestine Yong

Jestine Yong — Mon, 17 Dec 2012 13:04:36 +0000

In reply to Simon.

Hi Simon,

The inverter ic tl1451 is very robust and you need a scope to check on the output. In your case you need a powerful torch light to shine on the display. Sometimes the display too dim and you really need a good backlight to shine on it. Check the hv transformer with your ohmmeter and both the transformers should show almost the same ohm in primary and secondary side. We can check the backlight using backlight tester or through comparison method (by using another good working backlight). If this model is using the c5707 and the P-channel fet then you should check all of it and check also for bad tuning capacitors located nearby the hv transformers.

Jestine

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By: Simon

Simon — Sat, 15 Dec 2012 12:43:24 +0000

Hello Jestine

First of all, Thank you Very much!
There are not a lot of people like you, helping other people to Repair something, to learn something!
So i am also doing a little repairs as my hobby. I like to learn more about Power supplys, etc.
Actually ive done a lot of repairs, but with this one i have problems!
I am out of ideas....
I Got a BenQ 48.L1G02.A00 Power Supply here, which is not working right. (Those benq`s.. oh la la)
The Monitor switches on, shows the picture, after 2-3 seconds it turns off again... Normaly, i think, this is backlight issue... What i dont understand, is, the monitors LED is still green, on, after the CCFL is off.
But if i Light with a Flashlight in to the TFT, i cannot see anything, all blank!
I tested all Voltages, ive Got 3.3V 5V and 18V. I testet with the oscilloscope, all stable and no Ripple, so also the condensers should be fine. If the Backlight turns on, on startup, the 18 Volts sink to about 15 to 16 Volt. I think this is normal, or isnt it? Then if got 2 Lines coming from the LVDS Controll panel, I think its two times +3.3 Volt, if the Power switch is pressed. This is ok, and stays on high / 3.3Volt, even after the picture is gone. For me this means, the Controll board is still saying lets go. I already resoldered the HV transformers, the 7505 Transistors and Fets. I also testet the 7505 for shorts, negative. I then replaced the 7505, because i think its possible that they fail, during the load cycle, negative. One of my questions: How to check the HV Transformers? How to Check the CCFL bulbs? On the Board there is a TI TL1451A, PWM controller wich controlls the background light. As i know they have a two chanel Feedbak cirquit, which lets the Controller know if the two Cirquits are working, otherwidse it switches of. How can i check if the 1451 is switching off my backlight? Actually i checked Pin 10 Out2 and pin7 Out 1 with the osciloscope. pin7 / Out1 Generates a nice and smoot square wave during 2-3 seconds till it stops. Pin 10 / Out 2 generates the same square wave for about 1/2 to 1 second, then it goes to continous high till it stops.... Is this the problem? Is the TL1451A Faulty?
Thanks so far, in advance

Grreetings Simon

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By: Jestine Yong

Jestine Yong — Tue, 11 Dec 2012 23:10:58 +0000

In reply to Khonyot.

HI Khonyot,

Then try sss7n90 but before that make sure no other bad components in the surrounding circuitry.

Jestine

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