Philips 37" LCD 37pfl7662d/05

[vinceroger69]

Re: Philips 37" LCD 37pfl7662d/05

Not conected to anything if you look at the picture theres no wires going to the pins hence Nc.

[michael dranfield]

Re: Philips 37" LCD 37pfl7662d/05

i

Okay, so I ordered the replacement transformer and removed the old one. Well it is very clearly failed; there is a black mark in one side of the secondary winding, which has also burned the PCB silkscreen. It's in the top right corner.

What causes these transformers to fail? I thought transformers were generally quite reliable.

I think you will find its the 90 degree bend round the sharp corner that causes the failure .

[ReeceyBurger123]

Re: Philips 37" LCD 37pfl7662d/05

i

I think you will find its the 90 degree bend round the sharp corner that causes the failure .

As well as heat and age

[michael dranfield]

Re: Philips 37" LCD 37pfl7662d/05

The inverter transformers on darforn boards are particularly troublesome by far the most common problem is a change in resistance of one of the secondary windings causing an inverter out of balance circuit to trigger.the secondary windings consist of 3 or 4 strands of fine wire twisted together and due to thermal expansion on the 90 degree bends round the sharp corners exiting the transformer a single strand can snap hence the change in resistance of the secondary winding .the faulty transformer will usually go high in resistance by one third of the value of all the other transformers.