Benq Power Supply DS-1107A

[Jimisnotabot]

Howdy all, I recently had my Benq FP767-12 stop working on me. After some investigating, i'm sure it's the power supply. I've checked the caps visually and the fuse inside the monitor and all seem fine. I decided i'd first try to re-solder the components before I'd start replacing caps and FET's.

This is where I slipped up. During the course of the resoldering I think I may have soldered a few components together that should not have been. I blame my shoddy vision.

Anyhow, would anyone out there have an electrical schematic for the power supply board DS-1107A or a high resolution picture of the back of the PCB so I can check the components to make sure I havent stuffed up?

Any help would be appreciated.

[mekktom]

Re: Benq Power Supply DS-1107A

Hello,
I had a problem with the same monitor. After hours of search I found a russian website where you can download schematics for this panel. (and for much more models...) Fortunately the documents are in english.

link

You did not tell about the failure of the monitor, but if it is the backlight inverter, usually the Q739, Q740, Q759, Q760 transistors (type 5707) are dead. Check PF751 fuse as well.

Hope this helps.

[EGuevarae]

Re: Benq Power Supply DS-1107A

You did not tell about the failure of the monitor, but if it is the backlight inverter, usually the Q739, Q740, Q759, Q760 transistors (type 5707) are dead. Check PF751 fuse as well.

Hope this helps.

I agree with mekktom on that one. That are the common failure among that model. You should replace them and resolder the transformer contacts.
And welcome both to Badcaps.Net

[nico]

Re: Benq Power Supply DS-1107A

Hello,

I have the same problem with benq board, ds1107a, 48.L1A02.A31, but I don't find the transistor Q739,740,759 and 760.
I don't find the fuse too.

thank for help me !!

[Bobdee]

Re: Benq Power Supply DS-1107A

Hello,

I have the same problem with benq board, ds1107a, 48.L1A02.A31, but I don't find the transistor Q739,740,759 and 760.
I don't find the fuse too.

thank for help me !!

hello
Go to this link
https://www.badcaps.net/forum/attach...chmentid=11049
#
The fuse is on the right hand bottom corner of the white rectangle heatsink left side of the board three quarters up
The transistors are
Two in the middle of the 4 transformers on the bottom of picture one on top of the grey box capacitor another at bottom
the other 2 are to the left of the 4 transformers
Dont forget to resolder the 4 transformers after you done repairs or the new parts will go again probably

[nico]

Re: Benq Power Supply DS-1107A

I have replaced all the transistors, but I have 2 that become very hot, the 2 are at the left of the transformers, the self(solenoid?) above the transistors was very hot too.
No output at all !!

[Bobdee]

Re: Benq Power Supply DS-1107A

I have replaced all the transistors, but I have 2 that become very hot, the 2 are at the left of the transformers, the self(solenoid?) above the transistors was very hot too.
No output at all !!

That capacitor (solenoid) C801 will need replacing
and best to replace C802 as well on the inverter, If your P/Supply was at fault then chances are both sides of inverter would be hot
So your problem sounds like its the Inverter or CCFLs
Did you resolder the 4 transformers???
You have not told us anything about the problem
Are the backlights working fully, briefly, or not at all???
bob
When you replaced transistors,did you replace with same type???

[nico]

Re: Benq Power Supply DS-1107A

My monitor run for a few second before coming black, so backlight working briefly. but since I changed the 4 transistors, it didn't run and became very hot like I describe in my last post.

I resolded the 4 transformers. I didn't use the same transistors because i can't find, I used mosfet, this one:
https://cdn.badcaps-static.com/pdfs/...c0868d5c4f.pdf
I think they are good.
I try to change the capacitor and I give you result after.

thanks for help !!!

[Bobdee]

Re: Benq Power Supply DS-1107A

My monitor run for a few second before coming black, so backlight working briefly. but since I changed the 4 transistors, it didn't run and became very hot like I describe in my last post.

I resolded the 4 transformers. I didn't use the same transistors because i can't find, I used mosfet, this one:
https://cdn.badcaps-static.com/pdfs/...c0868d5c4f.pdf
I think they are good.
I try to change the capacitor and I give you result after.

thanks for help !!!

If the old transistors were C5707s or 6s then they are readily available on EBAY just search 2SC5707 or 2SC5706
It may be that the fault is in the side thats not heating up and the other pair are getting hot because they are not the correct ones, as I have read in other threads that diffrent transistors get very hot but you have said you put mosfets in this, that could be risky as the are a diffrent component

[nico]

Re: Benq Power Supply DS-1107A

If the old transistors were C5707s or 6s then they are readily available on EBAY just search 2SC5707 or 2SC5706
It may be that the fault is in the side thats not heating up and the other pair are getting hot because they are not the correct ones, as I have read in other threads that diffrent transistors get very hot but you have said you put mosfets in this, that could be risky as the are a diffrent component

OK, the old transistor were C5707s, i found them in farnell, i'll command them, normaly I 'll receive them on thursday ...
I'll give you some new
many thanks

[nico]

Re: Benq Power Supply DS-1107A

hello,

I received my components today, very fast farnell !!!
so I have change the 4 transistors and it's ok now !!!

many thank for your help !!!

[mecklan]

Re: Benq Power Supply DS-1107A

i have an FP767-12 / Q7C3. 4x 2SC5707, 2x MosFets and fuse were replaced. Thereafter, the monitor can only be manually switched on/off with the power button, so no more about the connection cable or the PC. What could still be broken?

[EGuevarae]

Re: Benq Power Supply DS-1107A

i have an FP767-12 / Q7C3. 4x 2SC5707, 2x MosFets and fuse were replaced. Thereafter, the monitor can only be manually switched on/off with the power button, so no more about the connection cable or the PC. What could still be broken?

Short in the BL_ON line/signal. May be a recently soldered components. Double check your soldering on the MOSFETS and Transistors.

[Phlashman]

Re: Benq Power Supply DS-1107A

This board is completely different from the DS-1107A I'm testing??? Although the numbers do correspond with the parts.