Well, b4 giving up, I ordered T801, the switching transformer. It took ages to arrive (Samsungparts had it on back order) but I finally got hold of it today, I soldered it in place, et voil=E0!!!!!! IT WORKED! So it was T801 after all Thanks for all the advice on this problem. I feel a little bit older and my hair is a little more scarce (if possible) after all I ran in circles biting my tail with this set. You all have fun, if possible Jorge PS Actually it's a 32" set and I don't remember the model (I only brought the mainboard) but chassis is the K51A, identical to the model I posted ************************************************** On the 06/02/04 , Jorge Camboni, GY Electronics, Richardson, TX (MYSELF) wrote this desperate message in a bottle: " I am about to give up with this. It's a Samsung K51A chassis and the main power uspply is giving 10 volts to the HOT collector and the rest of the voltages are low by the same proportion.. It uses a 3S1265H as the switching regulator and I already tried 2 different new replacements with no luck (actually, the schematic shows a 3S1265R and I tried a R and a RF -it makes no difference, the RD is totally isolated, the R has a metallic tab-) I measured component by component, the diodes, caps, ICs and resistors are all ok, there is nothing overloading the secondary - cold side of the= power supply, I actually disconnected branch by branch and nothing changed. Besides the secondary voltages which are dramatically lowered to a mere 10%, the voltages at the IC are the following: pin 1) has the correct voltage,=20 sometimes reading higher because it is oscillating somehow. pin 3) -VCC- has between= =20 11 and 13 volts, never reaches 17V as the schematics shows; voltage goes up and down all=20 the time. pin 4) has nothing, schematic shows .9V, Pin 5 has nothing or a few mv,=20 though schematic says 8.2V that is the sync/feedback pin, it is connected to T801, maybe=20 here applies the less-than-10% rule, as with the other windings. Besides that, if place a 60 watt bulb as a load on the 130v (leaving the=20 HOT collector floating first), the voltage goes still lower, down to maybe 3 volts or so.=20 Conversely if you leave all the secondaries floating, the 130 volts raise to nearly 70, but goes=20 immediately down with any light load you place on it or on the other low voltage rectifiers. I'm about to give up. The only unchecked/unchanged component is T801, but=20 it CAN'T be... Any help will be greatly appreciated TIA Jorge" Jorge Camboni, GY Electronics, Richardson, TX =20 ----------------------------------------------------------------------------- Lost Password: http://www.tech-assist.org and select "Login Problems?". Email Archives: //www.freelists.org/archives/techassist/