Re: Benq BL3200PT with a cooked PSU.
What was interesting with my monitor was that there was a tiny inspection hole cut in the metal plate covering the circuit boards. The hole let you see whether R616 had burnt out. This resistor was between the transformer and pin 16 of the IC. I'm guessing it was there to let the technician know that the IC had failed without having to further disassemble the monitor. Maybe they don't bother when they see that. I'm just curious to know if your monitor has a similar design?
the.norbulus
Member
Last Activity: 03-07-2023, 08:59 AM
Joined: 04-07-2019
Location: Melbourne
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Re: Benq BL3200PT with a cooked PSU.
Well done finding that! I assume your monitor is back up and running? I was only able to find the failed IC on my PSU because it had affected other components around it. Also I never would have got anywhere without help from people on this forum. I hope this thread helps other people out of similar problems.Leave a comment:
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Re: Benq BL3200PT with a cooked PSU.
Thanks R_J. I saw a similar problem in another thread (but vertical) and the suggestion was the LVDS. I'll have a look.Leave a comment:
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Re: Benq BL3200PT with a cooked PSU.
Well I thought I was done! After reassembly I got intermittent vertical lines on the whole screen when I powered it on with no source connected. They went away though so I tried not to think about them. When connected to a PC everything was fine for about 30 minutes and then they came back and now they won't go away. If these look familiar to anyone I'd appreciate any advice.
I will try re-seating the connectors and maybe cleaning the logic board with flux remover but beyond that I'm stumped.
The lines are:
- vertical,...Leave a comment:
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Re: Benq BL3200PT with a cooked PSU.
She rides! I've just tested the board after replacing the TEA1751T and the resistor didn't burn up. The output voltage is 11.98V and nothing else went on fire
Next stage will be replacing the remaining caps and reassembly.
Thanks again for your help R_J. You were right about the IC....Leave a comment:
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Re: Benq BL3200PT with a cooked PSU.
This is just a quick update if anyone's interested. I've decided to go ahead with replacing the IC as I'm not sure what else I can do. I neglected to follow R_J's sensible advice for removing the old IC and things didn't go quite as planned. I didn't know they glue the the chips down! I wicked of the solder as much as possible and then used a heat gun to soften what remained. One side must have been hotter as it came off cleanly then the glue must have broken and then the other side came up with the tracks. I think the damage can be fixed though....Leave a comment:
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Re: Benq BL3200PT with a cooked PSU.
Ok, results time. I have tested the following components and replaced some of the caps. After that I replaced the burnt resistor with a 10k 1/4 watt metal film and powered the board up. The resistor instantly started smoking and I cut the power. I guess at least I haven't created any new problems?
R623 & R651 tested OK
Q601 tested OK
C615 & C625 tested OK (replaced with Rubycon YXF)
Pin 16 to hot ground - no continuity
R_J, when you said test the other mosfet you mentioned Q601 which...Leave a comment:
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Re: Acer B326HUL power supply dead
Thanks for the reply You're back up and running now which is the main thing. I hope it didn't cost you too much.
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Re: Acer B326HUL power supply dead
Hi fred41, you and I seem to be in a similar fix. I have a Benq 32" with a dead psu and the board is similar to yours. Also the fault on mine seems to be in the same general area as yours (around the TEA1751)
Could you please tell me the value of the resistor on your board between pin 16 on the TEA1751 and the transformer? Mine has burnt out.
Have you had any luck getting yours going?
Here's my thread: [url]https://www.badcaps.net/forum/showthread.php?p=890830#post890830[/url]Re: Acer B326HUL power supply dead...Last edited by the.norbulus; 04-15-2019, 10:00 AM.Leave a comment:
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Re: Benq BL3200PT with a cooked PSU.
Hi R_J, thanks for your help, I really appreciate it. I went googling for the IC but what I was reading off it was 'A17511' which is only partial and also wrong! Knowing what the chip is demystifies things and makes the problem seem almost solvable. Not looking forward to de-soldering the little bugger though if I have to. I see from the datasheet that pin 16 controls high-voltage start-up which I guess makes sense.
I will get busy testing the components you've mentioned and post my findings.
Thanks again
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Benq BL3200PT with a cooked PSU.
Well from what I can see I seem to be the first person who's 32 inch BL3200PT has lost power. A couple of months ago it went completely blank (including lights) and I could smell some hot smokey electronics.
The first problem I came up against is that they aren't a very common monitor so there's no useful information about them online. I haven't been able to find a service manual (on electrotanya) and once I got it open I couldn't find any reference to the power supply model online either!
The caps look fine visually. There's a guy fixing benq psus on youtube who says they are the... -
Re: New Members - please post your introductions here
Hi everyone, nice to be here
I've replaced the odd bad cap in my time. Mostly Samsung monitors and PVRs. Every time there's been some awesome person who has done the hard work of diagnosing the problem and teaching everyone else. Well, now I'm in uncharted territory with a Benq monitor. If I can crack this one (hopefully with a little help), I'll post the result and be able to give something back.Leave a comment:
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