Diodes in SEG LED TV

[Murphy Maniac]

       
Hello All,
Although I have been repairing/restoring/renovating vintage equipment for more years than I care to remember, I am very new to solid state work and fairly clueless!
My flat screen TV has been in for repair on a previous occasion and has failed again in the same manner, totally dead. Opening it up I find a clearly fried diode, and a previous botched looking repair to a couple of nearby diodes.
From the picyures provided, could anyone please enlighten me as to suitable replacement diodes for D11, D14 and D15 please? I will be at Golborne on Sunday if it would help to see the board 'in the flesh'.
Many Thanks and Best Wishes,
Geoff.

[ppppenguin]

I hope that this is under guarantee and you're not paying for this so called repair. I'm no expert but those look like ordinary 1N4007 diodes which seem a bit unlikely in a switchmode power supply.

First, how old is the set? Does it owe you anything?

[Murphy Maniac]

The large store I bought it from in the local Retail Park is no longer there and the 'engineer' who did the 'repair' for me is no longer in business, surprise, surprise! Call me Mr.Cynical, but I am now firmly of the opinion that if you want something doing properly, do it yourself; nobody ever seems to do a proper job anymore. I decided to cut my losses and attempt the repair myself, which looks to be easy enough if only I knew what the components should be. I have a fair stock, and probably suitable diodes, I just don't know which ones they should be. I replaced the set when it stopped working for the second time and it is now taking up space in my workshop. Once repaired, it can resume operation in my snug, useful as it has a built in DVD player which its replacement has not. Cost is no longer the issue, like most of us, space is the prime consideration.

[ppppenguin]

Again, I'm no expert, but the common failures in switchmode PSUs are electrolytics. Is it apparent that any have been replaced?

Because of the bodged diode it's not obvious what the original circuit was.

[Bush Radio]

Check the diodes,they may be hi speed diodes such as UF4007.

Dave

[Murphyv310]

Probably not a bridge, most likely using higher rated diodes than the original.
These sets are made to a price not for long term reliability, I'm actually surprised they last as long.

[Murphy Maniac]

Had a good look around for any other obvious signs of distress and the only contender is the diode illustrated (D11). Electrolytics all look to be OK, although I haven't checked them.

[Murphy Maniac]

Bush Radio, I have not taken any notice of the markings on the larger diodes as they could well be non-original owing to the intervention of the previous repairer. D11 is so damaged that the marking are no longer visible.

[Murphyv310]

My post above has been auto corrected by my phone. It's not Bridge but Bodge, sorry about any confusion.

[Murphy Maniac]

Thanks Trevor, no confusion caused.