Logik l32digb20

[sordids999]

Backlight constantly flashing on and off,voltages fluctuating until i disable the invertor board then all voltages stable again

possible screen failure ?

thanks

[tom66]

Re: Logik l32digb20

BL ON steady? Check voltage across large 450V capacitor(s) on PSU.

[sordids999]

Re: Logik l32digb20

370 volt on the 3 big caps im trying to locate the bl on at present any ideas

[tom66]

Re: Logik l32digb20

Green or brown wires going to inverter. One is BLON and the other is DIM.
370V is a little low; does it drop when flickering?

[sordids999]

Re: Logik l32digb20

370 v constant and the BLON is reading 5.18v

[tom66]

Re: Logik l32digb20

24V to inverters OK? Also is that green or brown wire you checked? Note: green-to-chassis and brown-to-chassis.

[sordids999]

Re: Logik l32digb20

The brown is reading 5.18 volts the green is reading 1.33 volts but the 24 volt invertors are jumping from all over the place

[tom66]

Re: Logik l32digb20

It can be hard to tell if it is PSU or inverter. In my opinion it's a lot more likely to be PSU, but this isn't always the case.

What I would suggest is attaching two car headlamps, in series, to the 24V output. If you're short of them, Poundland sell them in packs of two (they're probably rubbish, but they're OK for a 65W load.) This will provide approx 65W load to the PSU, around 1/2 what the inverter draws. If that flickers, the PSU has an issue. You can also try adding a second set providing 130W if it does not flicker. 130W is about right for a fully functioning 32" inverter.

[sordids999]

Re: Logik l32digb20

I had a spare invertor tried that still the same so possible psu fault

[tom66]

Re: Logik l32digb20

The 370V PFC sounds low to me, if I were to focus on any particular area. Does that rise with the inverter disconnected?

[flocko]

Re: Logik l32digb20

Hi i have just repaired one of these this week the BLon comes out of the bottom of the Av board to the inverter. This set would not turn the backlight on and would not turn off to standby with side buttons or remote it was the 3.3 v regulator on the Av board in the bottom left corner second one up easy fix

[sordids999]

Re: Logik l32digb20

@tom no inverter disconnected still 370 volts
@ flocko mines different the side buttons and remote work fine on mine

Thanks

[flocko]

Re: Logik l32digb20

still check this regulator, i was told this one had flashing backlight then it failed to come on one day?

[sordids999]

Re: Logik l32digb20

do you mean this in the picture ive added and whats the best way to test it

[sordids999]

Re: Logik l32digb20

opps sorry forgot to add the picture

[flocko]

Re: Logik l32digb20

No not that one the one above marked 1117 33 you need to check for 3.3v on the center leg or the tab (north)i would check all the regulators as they seem to feed each other,all the rest are adjustable regulators so take a reading of all three legs 1/2/3 with the tab (north)up,reading 1/2/3 from left to right a good reg will read 1.25v higher on leg 2 then leg 1,so if leg 1 reads 1.5v leg 2 should be 2.75v, there are lots on here on how to test regulators just do a search.

[tom66]

Re: Logik l32digb20

Narrow the problem down. If you have steady BLON and DIM, then the main board shouldn't cause the flickering. Note: I forgot to mention to check PSON. It'd be a good idea to check that too.

[sordids999]

Re: Logik l32digb20

ok measurements in picture attached this tv is really intermittent now the backlight stays on but i can turn the tv On via remote or side button,but when i try to turn it off via remote or side button i have to switch it of via the mains switch

[tom66]

Re: Logik l32digb20

Middle most regulator, was pin #1 jumping around? That reading is odd, comparing to pin #2.

[sordids999]

Re: Logik l32digb20

now i cant give you that answer because i have just turned the tv back on and im now back to a flashing backlight and all regulator pins are now fluctuating