Forum > LCD TV forum
17pw20 overvoltage
jimca007:
although i understand what your saying regarding the inverter coming up ok on a bench test the symptom in a real world normal situ of a brief flash from the tubes and a dark picture would almost always be a bad inverter. could be a dodgy mosfet on the inverter on ideal voltage will pass ok but on the slight over voltage locks up with these symptoms i would be looking at the inverter before the psu its the wee flash that gives it away,
Turnip:
Good thought Jim,
What's the inverter Vic ? Quuq folks might have some - Chris
PS - Thought about tips - Council folks are now trying to save 'their' cash putting recycling to private firms eager to make a survival pound with very few 'Health and Safety' Local Council well pensioned clipboard farts still on the payroll, so pehaps some real recycling can start. Not yet thinking of burning my PCB panels for metal on the local beach - but surely real green recycling is good - just a thought.
vic_curtis:
Hi Guys, owing to rain stopping my efforts outdoors today, spent a bit more time looking at this and think I've
found the primary problem...R876 (30K 1%) had gone high to 33.5K. Replaced with a 30K and 24v rail is now sitting happily at 24.5v. Now to put the bits back together and see if I have a working set.
Incidentally, R876 could hardly be any more inaccessible! right underneath the edge of the heatsink. Must
admit after wiggling the original out I resorted to fitting the replacement on the reverse side of the board!
Vic.
jimca007:
Chris with being friends for quite some time with all the guys at my local refuse site ( tip ) I was fairly stunned to hear one of them tell me that all white and brown goods that now come into the yard are no longer sent for scrap but actually sold to a contractor who can either stip and sell parts or refurbish for resale not that it mattered to the guys who are still quite happy to give you what you what for a small gratuity it certainly explains all the clip board bean counters who seem to have sprung up in the last wee while .
Vic... well done indeed if that resistor fixes your prob wouldnt have thought it'd be an easy find !
vic_curtis:
Result!.... TV now fully working (just need to fit the full complement of fixing screws).
Was initially phased by getting nothing but a "No Signal" indication for both Analog and Digital. Then after
some reflection realised the previously tuned analog channels were showing no signal 'cause the transmitter has now completed its DSO so there is no analog signal. The lack of digital signal I eventually twigged was because the TV had come to me from another area and all the previously tuned channels were different in my area.
Must have taken me about another hour to get to grips with just how you get this beast to re-tune all the
digital channels, including realising I needed to put new batteries in the remote "Doh!". Now all seems to be working a treat.
More than pleased; what was threatening to be a scrap job ended up being fixed by a 12p resistor... just don't ask about the time! Just as well I was doing this mostly as a favour to a friend for his 89 yr old mum.
Cheers all,
Vic
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