Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

Hi, thanks for quick reply
Latest checks, using hot - ground.
Q913, B = 0v. E = 0.45v, collector is connected direct to hot ground. (other side of r931 = 0.54v) so must be a small current flow there.

I rechecked c910 each side in relation to hot ground. 110v & 2.7v ( so 108v axross the cap.). I also replaced zd 909 with a 9v1 still reads 2.7 v across.

I wonder if c947 c948 could be a problem although there not shorted.

Also the suspect ic i removed...

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

I just noticed zd 912 & r965 are not fitted & the schematic notes them as NC ( no connectio I assume) What do you think is the alternative supply path to pin 1 on the ic905. there is only 1.5 v on it, not enough to start the ic. Pin 6 has 313v. Note there is 150v accross c910.

I have replacedcaps c943 & c946.

Would appreciate if you have further ideas

Thanks Frank

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

Thanks for that info, gives me plenty to work with in isolating the fault. Im just waiting on delivery of some components ( unfortunately no tech shop nearby) and hopfully get it sorted in the next few days. Will let you know how it goes

Frank

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages

Hello, My name is Frank living in Galway Ireland.
I have carried out the following checks on the powerboard removed from the tv & powered up on the bench. The hot side has 313v. But no 24, 12 or 5v on the low side.
Using - on c7 as ground, i have measured the following on ic 105, p6 = 313v, p1= 1.6v, p3 = 2.7v. I note the scheematic shows 395v on the hot side, however I only get 313v ??
I have already replaced ic 905. V across zd909 is 2.75v

Your help is much appreciated...

Re: LCD Philips 47PFL4606H/12 - power supply doesn't start, no voltages



Hi,
Just signed up to day, have being following this line as I have exactly the same issue, same power board, only live voltage is 330v. No 5v or 12 or 24 v. Did you find the problem on yours, it may help me also?

Frank...