TECHWOOD 32940HD DEAD

[kennyc]

Hi guys ,TV has a 17pw25-4 power supply with the 2 lines of 3 diodes . Has a 17MB62.2.6 AV board . Is dead and has no stand by light . If I disconnect the AV board the 5v stand by voltage comes up but when connected it seems to be tripping. Thought AV board was faulty but had old one that sound goes off after 3 hours . Put that in and still not working . So dont know if its the chicken or the egg . Have changed caps on power supply . Any way of checking if its power supply or AV board ,thanks if you can help