Re: Rapid flashing screen Vistron LCD TV - PSU or Inverter or?
Thanks to everyone for your help and advice with this - much appreciated.
I've now ordered a Rubycon cap to replace the Lelon.
David
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Re: Rapid flashing screen Vistron LCD TV - PSU or Inverter or?
Thanks budm and selldoor.
I hadn't read the dim bulb idea before I put the main capacitor back in place and soldered in a wire to jump the damaged trace.
Plugged in and switched on and the TV works again... (!!)
[B]Does the jumper wire need to be particularly large in diameter? At present, I've used wire comparible to the other existing wire jumpers as per my image on post #23[/B]
I also remembered to give the soldered areas a good clean off this time...
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Re: Rapid flashing screen Vistron LCD TV - PSU or Inverter or?
Hi all,
Thanks for the advice so far but now I'm at a loss as to what to do next?
I tested the other MOSFETs on the board and they all had similar readings. Do I just put it all back together, replace the 5A fuse in the plug and repair the PCB trace and hope for the best?
I still have the option of a replacement board if it all goes bang again!
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Re: Rapid flashing screen Vistron LCD TV - PSU or Inverter or?
Ok, have removed the cap and tested as best I can... connected to DMM at 2000k ohms setting and resistance rises. Then tested voltage across terminals after 30 seconds or so and it read 0.2V
Photo attached shows top of board where cap was located. No obvious signs of damage here.
Did notice a tell tale "sizzle" as I de-soldered suggesting I had left flux on the terminals....
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Re: Rapid flashing screen Vistron LCD TV - PSU or Inverter or?
Ok, that's a good point. I didn't use loads of flux but didn't clean up very thoroughly either.
So effectively, the board heats up as it is working and then liquifies the residual flux which then runs and causes a short?
Would that be enough to cause the scorching and blow a section of the PCB away?
Silly question but, is it safe to short across the main capacitor (now removed from the mains of course) to make sure I don't get a jolt?
budm - thanks for the input although...
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Re: Rapid flashing screen Vistron LCD TV - PSU or Inverter or?
Hmm... plug fuse (5A) has blown.
Removing the power board shows major problem... its cooked!!
I can't see how I have managed to mess this up so badly. I was certain I kept the polarities matching the old cap...?
All the heat damage is around the replaced cap so what did I do??
For amusement only, photos attached as requested. Cap pins indicated with arrows.
A replacement power board is only £30 but is it likely that the other boards will now...
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Re: Rapid flashing screen Vistron LCD TV - PSU or Inverter or?
Erm... would you believe, it just went bang!?
Worked fine for a good few hours yesterday but turned on today (which reminded me to post the fix here) and after 30 mins or so, literally went bang!
I'm sure I heard a piece of something explode at the same time too.
Taken cover off and power board heat sinks are hot.
Perhaps the Lelon cap from Ebay was not the best choice!? It did have the same rating at the Samxon and was very similar in size...
I might just...
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Re: Rapid flashing screen Vistron LCD TV - PSU or Inverter or?
Just a quick update to this thread.
Received the new capacitor and replaced the suspected faulty one on the power board.
TV is now working 100% again - great result and thanks to all who offered advice!
Happy soldering!
David
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Re: Rapid flashing screen Vistron LCD TV - PSU or Inverter or?
Hi guys,
Thanks all for your input. Country is UK so 240V 50Hz.
I've already ordered a replacement for the main 150uF 450V cap on the PSU and will swap and test when it arrives.
My DMM is a mucho-el-cheapo thing... I'd normally only measure across low voltages, otherwise non-live components.
tom66 - thanks, that ties in nicely with my findings
selldoor - have taken an addition photo close up although no sure if it is what you wanted!
...
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Rapid flashing screen Vistron LCD TV - PSU or Inverter or?
Hi all,
After successfully replacing inverter caps on my Acer monitor last year thanks to info found on this forum, I've now acquired a 'broken' Vistron 32" LCD TV.
When powered on, the screen "strobes" rapidly as if the back light is failing to stay on.
This time I suspect it might be the power board but then again, I'm a complete novice.
After inspecting the caps on all the boards, the only one with anything of note is the large 150uF 450V Samxon on the psu.
Does anyone have any other ideas??
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Re: Something is blowing my Intel Little Falls 2 D945GCLF2 mobo!?
I've just plugged one of the boards into a standard ATX PSU and left for a while - the regulator/transistor took about 30 seconds to get noticably hot.
The southbridge chip also began to warm up a little.
The voltage across the regulator (outer pins) was 1.80V.
Think I'll start the project from scratch!!
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Re: Something is blowing my Intel Little Falls 2 D945GCLF2 mobo!?
Thanks PCBONEZ!
So, even though there's no obvious signs of life apart from the LED on-board, this regulator might be working ok? - Shame because I was hoping it would be an easy-ish fix!
Is there a way of testing with a meter? (Sorry for my ignorance)
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Re: Something is blowing my Intel Little Falls 2 D945GCLF2 mobo!?
Hi guys,
Thanks for the responses so far.
I have to say I'm no electronics specialist.. the PSU is a custom 12v in, car ATX. It is less than 8 months old and only used for 30 mins per day on average.
Here's a pic -
Someone has suggested the car alternator but for the second board, the car was not running and ignition was at ACC position.
I have tried both boards bare and get the same result - the transistor gets very hot, very fast BUT no...
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Re: Something is blowing my Intel Little Falls 2 D945GCLF2 mobo!?
Hi PcBonez
Thanks for the replies.
The boards both show ATX power is connected but will not power up - no fan spin etc. All that happens is the circled transistor gets very hot.
These boards first appeared in 2008 although I can see Nichicon PET written on at least 2 caps. Also used is Samxon, N.P.N(?) and Rubycon.
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Something is blowing my Intel Little Falls 2 D945GCLF2 mobo!?
Guys,
Sorry to just barge on here and post but I need so advice...
I have built a car PC running with an Intel Little Falls 2 mobo (D945GCLF2).
It has been running great for months and then suddenly decided to 'die' the other day. The mobo was mounted in the dash but not particularly well protected so I decided something had shorted as the M2-ATX car PSU was apparently running fine and the green power indicator on the actual motherboard was lit but with no other signs of life.
I purchased a replacement board together with a mini ITX case...
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