Fix for Benq FP737s 17" (Q7T3)

[imalearner]

Re: Fix for Benq FP737s 17" (Q7T3)

Yours are almost too small to be helpful.

First step, I have marked up the usual suspects for this monitor. Check the transistors I have circled to see if any are shorted. I've also circled what I believe is a picofuse; the identifier is too small to read. Verify that is intact.

PlainBill

Thanks PlainBIll for getting back. I'll be testing away as soon as I get back to my workshop/shed. Thinking that the upload failed last time because the images were too big....I just resized them. It may also have been just a poor wirelesss signal from my shed too! So, I'm putting this one back up just to see if that is more helpful....for future enquiries perhaps. This is max size for my camera. Hopefully part identifiers should be more legible. Fingers crossed.

Cheers,

Imalearner

[PlainBill]

Re: Fix for Benq FP737s 17" (Q7T3)

So here they are...I hope!

I believe the site has a limit of 2000 pixels on a side. My camera takes pictures at a resolution of 2278 x 1712; too big to upload. I've found that reducing the pictures to 1024 x 720 gives a large, usable picture. Yours are almost too small to be helpful.

First step, I have marked up the usual suspects for this monitor. Check the transistors I have circled to see if any are shorted. I've also circled what I believe is a picofuse; the identifier is too small to read. Verify that is intact.

PlainBill

[imalearner]

Re: Fix for Benq FP737s 17" (Q7T3)

xx pics upload failed twice xx Will try again later!

So here they are...I hope!

[imalearner]

Re: Fix for Benq FP737s 17" (Q7T3)

Oh, pictures help. See the FAQ on inserting pictures.

PlainBill

Thanks PlainBill for that. My eyes see much less now than my camera can, so I'll post these anyway. I don't have a history for this monitor/board, but it looks overall, like the whole board solder connections are in some state of corrosion, or overheating perhaps....I dunno. Might be better to reconsider replacement of the whole board rather than repair?

Any comments gratefully accepted.

imalearner..

xx pics upload failed twice xx Will try again later!

[PlainBill]

Re: Fix for Benq FP737s 17" (Q7T3)

Greetings to all on this very informative forum. I'm cutting my teeth as a hobbyist in this field of work and I have stumbled upon your website. It's so jammed packed full of info on this particular monitor, that I am about to blow a fuse myself!!! Some of the mods may be outside of my skill level at present but hey, we all start somewhere right? Not sure exactly where I should start but if anyone could kindly point me in the simplest of terms, I would be very grateful. Thanks in advance.

My symptoms....monitor turns on momentarily, enough to see a flash of the Benq Logo, then it shuts off ......and the green power light goes out too. Now I hope this is enough for a simple solution........but since this monitor seems to have a whole history of poor design...maybe I shouldn't hold my breath.

All replies welcome.

It's teh same problem as found on any number of these monitors. Starting at the beginning of the thread may have given you this information.

After replacement 4x2SC5707 2xFU9024 and the fuse 3A all was well again. I resolder joints on the inverter transformers.

In your case,check the 2SC5707's. If any are shorted, replace the lot; likewise for the FU9024. Because you are getting the flash, the fuse is good. Also, resolder the transformers; that was the original cause.

NOW it may be that the transistors are fine. Then check the output voltage of the power supply; if good, see if the monitor comes on when you push the power button.

Oh, pictures help. See the FAQ on inserting pictures.

PlainBill

[imalearner]

Re: Fix for Benq FP737s 17" (Q7T3)

My 2SC5707s arrived. Soldered them in, and my Benq FP731 works!

I did resolder the connections to transformers.

Greetings,
Steven

Greetings to all on this very informative forum. I'm cutting my teeth as a hobbyist in this field of work and I have stumbled upon your website. It's so jammed packed full of info on this particular monitor, that I am about to blow a fuse myself!!! Some of the mods may be outside of my skill level at present but hey, we all start somewhere right? Not sure exactly where I should start but if anyone could kindly point me in the simplest of terms, I would be very grateful. Thanks in advance.

My symptoms....monitor turns on momentarily, enough to see a flash of the Benq Logo, then it shuts off ......and the green power light goes out too. Now I hope this is enough for a simple solution........but since this monitor seems to have a whole history of poor design...maybe I shouldn't hold my breath.

All replies welcome.

[steven.va]

Re: Fix for Benq FP737s 17" (Q7T3)

My 2SC5707s arrived. Soldered them in, and my Benq FP731 works!

I did resolder the connections to transformers.

Greetings,
Steven

[Bobdee]

Re: Fix for Benq FP737s 17" (Q7T3)

Yes in one
You need to go 4 of same type
Easy and quick to get 2SC5707s on ebay

[steven.va]

Re: Fix for Benq FP737s 17" (Q7T3)

You need to go with 4 of the 2SC5707s or 4 of others, but the TIPs are known to run hot (not recomended)

Could that explain the shutting down of the inverter after 4-5 seconds?

Greetings,
S.

[Bobdee]

Re: Fix for Benq FP737s 17" (Q7T3)

You need to go with 4 of the 2SC5707s or 4 of others, but the TIPs are known to run hot (not recomended)

[steven.va]

Re: Fix for Benq FP737s 17" (Q7T3)

Hi All,

I got a Benq 17" Q7T3 TFT like you all.
It had it's two 2SC5707 shorted, FU 9024n shorted, 3A fuse open.

So far I have replaced the fet with an IRF9540, wich according to
my suppier is a good replacement.

I replaced the two broken 2SC5707's with TIP132. I know this is not good, however it was the only thing I could get my hands on...
Resoldered the transformers, resoldered other suspicious joints too.

Powering the TFT up:
Well: it did not go up in smoke

Backlight works, and it shows the "Benq" logo. Went out after 4 seconds.
I Tried that again:
So I connected a PC and it showed the window desktop just fine, but again, the monitor shutted itself down after a few seconds (faster every time)

Things tried with data cable disconnected:
- Connected CCFL lamps to inverter 1 (the good one)
---> Screen is lit, shuts down after a few seconds
- Connected CCFL lamps to inverter 2 (the repaired one)
---> Screen is lit, shuts down after a few seconds
- Connected CCFL lamps to inverter 1 & 2
---> Screen is lit, shuts down after a few seconds

However: when feeling at the TIP 132 transistors they get HOT.
I can barley touch them with my hands.

....while the two remaining 2SC5707 are actually cool running.
Is the TFT shutting down because of the improper transistors used, or is there another fault I can check that overheats the TIP 132's

Should I swap the two remaining good 2SC5707 with TIP132 too just to see that they overheat too or not?

Greetings and thank you in advance!
S.

[PlainBill]

Re: Fix for Benq FP737s 17" (Q7T3)

Check them, how? they're brand new...from the 7 piece kit on eBay. Would they fry instantly? Solder looks good.

Use an ohmmeter.

Yes, they can short instantly if the problem that caused them to short is still present.

PlainBill

[fety]

Re: Fix for Benq FP737s 17" (Q7T3)

That ticking sound is a symptom of the power supply shutting down and restarting. Have you checked the transistors you installed?

PlainBill

Check them, how? they're brand new...from the 7 piece kit on eBay. Would they fry instantly? Solder looks good.

[PlainBill]

Re: Fix for Benq FP737s 17" (Q7T3)

Well CRAP!! It didn't work! I got the kit on ebay and replaced all 7 parts and resoldered the transformers as well as resoldered a few other suspiciously lame looking solder joints. Nothing shows up on the screen now, just the power LED blinks about every 1.5 seconds AND I can hear a faint tick sound. Like what HelpQuick experienced... What is this a symptom of? what can I try next? replace all/most of the caps? Btw, I'm not an electrical guru, I just have a A. W. Sperry AMM to work with so don't ask me to test this or that if I'm not capable of doing so. Thanks

HEEEEELLLLLLLLP!!!!!!!!

That ticking sound is a symptom of the power supply shutting down and restarting. Have you checked the transistors you installed?

PlainBill

[fety]

Re: Fix for Benq FP737s 17" (Q7T3)

Well CRAP!! It didn't work! I got the kit on ebay and replaced all 7 parts and resoldered the transformers as well as resoldered a few other suspiciously lame looking solder joints. Nothing shows up on the screen now, just the power LED blinks about every 1.5 seconds AND I can hear a faint tick sound. Like what HelpQuick experienced... What is this a symptom of? what can I try next? replace all/most of the caps? Btw, I'm not an electrical guru, I just have a A. W. Sperry AMM to work with so don't ask me to test this or that if I'm not capable of doing so. Thanks

HEEEEELLLLLLLLP!!!!!!!!

[fety]

Re: Fix for Benq FP737s 17" (Q7T3)

LOOK people! 9 times out of 10, Cold solder joints DO exist on the board. Looky what I found on mine! BE SURE TO REMELT OR (better yet) RESOLDER THE TRANSFORMERS!!!

btw, this is from a Dell E172FP / E172FPb

[EGuevarae]

Re: Fix for Benq FP737s 17" (Q7T3)

Hi all,

Go the parts from ebay (Actually bought 2 sets), replaced all 7 parts.
Before it was completely dead, now with the new parts, it actually shows benq logo, or destop image, but just for 2 seconds and then nothing. Any idea?

I kind of gave up, so if anybody from Australia is interested in buying the parts, or the screen for further part such as casing etc...I suppose the screen is still good...
Anyways let me know.

Resolder the transformers and other common solder points (see all the thread). You'll be fine.

[Caloute]

Re: Fix for Benq FP737s 17" (Q7T3)

Hi all,

Go the parts from ebay (Actually bought 2 sets), replaced all 7 parts.
Before it was completely dead, now with the new parts, it actually shows benq logo, or destop image, but just for 2 seconds and then nothing. Any idea?

I kind of gave up, so if anybody from Australia is interested in buying the parts, or the screen for further part such as casing etc...I suppose the screen is still good...
Anyways let me know.

[enterthehatrix]

Re: Fix for Benq FP737s 17" (Q7T3)

Hey guys.

Got all my monitors working except one, which virtually burst into flames.

The good news is that the LCD and the little VGA board still work.

Has anyone else tried to manually power this up? I intend to use the screen as a light weight portable screen backlit by LEDs and powered by batteries (if possible)

Could someone try this and if it works, could they do a diagram of the VGA board and point out which pins require what voltages, etc?

On the schematic, it has BLT_ON and BOLT_ADJ which I assume is the backlight, PW_DOWN (no idea), Volume On/off and volume (not used), GND, P12V, P3.3v, +3.3v, and +5v

What's the difference between P3.3v and +3.3v?

[EGuevarae]

Re: Fix for Benq FP737s 17" (Q7T3)

Hi Everybody,

Thanks all of you for the useful postings which help me to repair a BenQ FP731.
It does not have any display with the green LED stays on.

Things done
-------------
1. Replaced fuse (BEL MS 3A), PF751 is open-circuit. I used a 2A pico fuse because I do not have a 3A fuse on hand.

2. Solder inverter transistors (2SC5707), Q739, Q740, Q759 and Q760. The solder cracked when I moved these 4 transistors.

3. Solder power MOSFETs (FU9024N), Q743 and Q751. The solder cracked when I moved these 2 MOSFETs.

4. Solder transformers, T751, T752, T753 and T754. No solder cracked, just re-solder to prevent dry joints.

5. After power on, left half of the monitor displays information correctly but right half has pink background with a continuous black line in the centre of the screen.

6. Remove the two flex-cables and clean the contacts (dirt found) with alcohol.

7. Power on and the monitor is in working condition.

Once again, thanks all you for the important information.

Have a nice weekend...Yong Seng

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