Re: LF501EM5F No Power, Chirping/Beeping Transformer
Have never had 3.3vdc. Doesn't matter if the ribbon cable is plugged into the board or not. 3.3 is not present. As far as the chirping that only happens when the ribbon cable is plugged in. I have not tried to plug the ribbon cable in with the resistor soldered in place.
Have never had 3.3vdc. Doesn't matter if the ribbon cable is plugged into the board or not. 3.3 is not present. As far as the chirping that only happens when the ribbon cable is plugged in. I have not tried to plug the ribbon cable in with the resistor soldered in place.
OK, then we need to look at the ALL+3.3V standby power supply section first then, we know we do have the main DC 160V to run the standby power supply section, we will be working on the power supply board without any other board connected to it at this point and try to get the 3.3V working first.
I will have to look at the diagrams. BTW, did you do any testing of the Diodes on that power supply board?
Re: LF501EM5F No Power, Chirping/Beeping Transformer
OK, we need to find out what dcv you have on the SMD SMPS IC601 (FA5640N please verify that is the P/N as printed on top of the IC) in the primary side, we need the DCV readings of all the pin with ref to the GND pin pin 4 (or use the negative leg of the main filter cap as the GND ref point).
Be real careful not to touch anything since you are working in the primary side of the circuit.
Re: LF501EM5F No Power, Chirping/Beeping Transformer
Measure all pin outs on the PSU, post pin name with voltages measured. TV on and TV off, so we have a start point. I went back, but that isn't your thread. Use GND pins 9-14 as your GND reference.
Re: LF501EM5F No Power, Chirping/Beeping Transformer
The Main board is disconnected and there is a resistor soldered from the All+3.3volts to the p-on. Budm was stating that 3.3vdc isn't present so we were trying to figure out why that was. He had me start with ic601 and there voltages.
slk001 I'm assuming you are talking about the surface mounted caps on the back side?
Sorry, I meant D605, D606 and D607. These are your booster diodes, which should boost your voltage to ~300VDC.
The Vcc pin on IC601 (PIN 6) is right at cut-off voltage (11V). This means that your driver IC is probably going in and out of shutdown. The voltage on PIN 6 should be in the 20V range.
Re: LF501EM5F No Power, Chirping/Beeping Transformer
Lifted one leg of D605, D606, and D607 and they were all in good shape. Since it was so damn fun I did every diode on the board. All diodes tested good. As far as the voltage on pin 6 of IC601 it is the same as it was the last time. Still 11.33 volts as is D614. D614 is hooked directly to pin 6 of IC601. D614 also checked good. And as long as I was checking I check as many of the surface mount diodes I could find and they all measured fine.
Re: LF501EM5F No Power, Chirping/Beeping Transformer
c611 is measuring 17 ohms with esr meter. Seems high but I'm not at all familiar with ceramic caps. I'm going to try and find a parts board from a different TV and try find one with the same value and change them out.
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