AD301M24-4N1 low secondary?

[confused_ant]

Hi
i have a 42" LCD tv that recently decided to display green and then started to give artefacts on the screen. I looked inside and found a blown cap on the power supply. tho the power output was good, but i replaced the cap and then decided to do all the secondary caps on the outputs, i tried the tv again but no change to the dodgy picture, i then changed the T-con board and again no issue and so assumed it was the main signal board, I tried the old heatgun over the signal board incase it was a dry joint but no use, and so went to order a new main board. However when i tried the old board one last time i didn't get any picture at all, i get the standby light and it flashes when i press power but nothing.

So i measured voltages - I have 5v where it says 5v out (this was 4.8ish before i changed the caps) but i have only 3.84 volts on the 12v rail, when i press the power button there is noise in response - a high frequency noise that makes me think there is activation of the transformer, but no change in voltage, there is a on off lead from psu to motherboard but this has about 0.1v on it in standby and then goes upto 0.4-0.5v when the tv is turned on. I am questioning if the capacitors i have used have caused the issue if they might not be low esr enough? but there is also a possiblity that the old cap blew because of a fault.

There is a repair kit listed on repair sites for this tv that mentions lots of resistors but having had a look with my mm they all seem to be fine to me.

Can anyone advise me where to go next with testing this?

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[tom66]

Re: AD301M24-4N1 low secondary?

Those look like NIC capacitors, and will probably not work.

[confused_ant]

Re: AD301M24-4N1 low secondary?

they are NIC - i that my mistake?
would they mess anything else up or just cause lack of action?

[confused_ant]

Re: AD301M24-4N1 low secondary?

right... replaced those with the original ones, and used a working one from off a junk board to replace the broken one, plugged it in and there was smoke... not a pop or a bang just a slow generation of smoke for about 20 seconds, and the 5v line has gone, the 12 and 24v work perfectly so my bad with the caps there! but no idea why the 5v has gone now
any idea what component trends to smoke slowly? it was from around the 5v transformer but didn't seem to come from a specifif component.... just pulled the 5v transformer and but not 100% what i;m checking... there are 4 pins going in 2 pairs i assume with 0 ohmes between each pair and one pair coming off with again o ohmes between them. theres infinite between primary and secondard sides.

[confused_ant]

Re: AD301M24-4N1 low secondary?

i think its my Schottky diode thats gone!
when i test it one way i get 34k ohmes - the other way the auto ranger on my meter just goes nuts between kilo/mega and never gives a reading which i guess is a no no?
and if i try continuity on it i get a negative both ways round,