Hi all,

 

My MX4000 acts strange. When connected to mainpower the standby led does not lit. It flashes shortly when the mainpower is disconnected. Arcondingly to the repair manual across Cp there should be 300 volts, I messure 318 volts. I assume that is ok. I have messured TR1 and C12, and both are not broke. When I messure across C52 (should be 8 VSB) I messure 5.2 volts and there is no ripple. Messuring across C53 i get some very bad negatibe spikes, and not anything near the 8.5 volts that the repairmanual says. Actually all the T2 secondary voltages are either spikes or not the values specified in the repairmanual. T2's ferrit is broken, and I have glued it together. How much will this effect the transformer??

Looking forward to hear if any has any clues

caio

I would think the line output stage is loaded. the line output transistor often goes short circuit with this symptom. I also recall a diode ( I think D32 or 34) goes short - rectifier for one of the secondary supplys...

Hi BEOKNOW,

 Thanks for the suggestion. It was right. D36 was broken. I messured 0 ohm from both directions. D34 which is the same type of diode messured right. I will try to find out where I can get this diode, and will return, either with more questions or with a happy face :-)

 Regards...

Follow up.

Thanks for the advice. I have now changed D36 (FESF8BT) to a BYW80-150 and the tv works fine. Thanks for being a genius and helping us all out.

 

Regards Morton.

Thanks for the update & conclusion. Always helpful & interesting.