Hi,
I picked up a broken Sony 51WS520 television as my first big screen TV. It blinks 4 times on power-up. The manual states that this is a vertical deflection problem or +/-15V problem to the vertical deflection IC.
I set the multimeter on DC mode and measured the +/-15V going to IC5101 (LA78045) on the D board. The -15 volts rises to -8 volts before the TV turns off the power due to no vert. deflection. The +15 rises to 8 volts and then falls slowly back to 0 volts after the TV turns off.
I checked the +/-17V to the convergence ICs. The +17V rises to +10v and the -17v rises to -10v before the TV turns off due to code 4. The voltages stay at that level for a while after turn off.
I measured the -15V, +15V, +17V, -17V voltage wires/traces to ground. None of them have a direct short so I am guessing no capacitors are bad. I do not have an o'scope so I am going to try and replace IC5101 when it arrives in the mail.
Do those voltages sound correct for a 4 blink error. That is, they start to come up to the value stated in the spec but don't fully make it there due to the error causing the TV to turn off?
Thanks
Update: The LA78045 arrived and I should be able to install it today. Hopefully this fixes the 4 blink problem.
Installed the new LA78045 and the 4 blink problem still exists. Measured the power supply voltages and they seem low. Looks like a power supply problem causing the 4 blink error.
Update:
The +135V has a short. All voltage to GND measure high resistance except for +135V. The +135V line measures 5.5 ohms to ground. Measuring after the 2.2 ohm resistor on the 135V line it measures 3.5 ohms to ground. Upon further measurements it looks like the short is in the Horizontal deflection circuit. Probably another hour or so to find where the exact location of the short is.
Any typical components that short out in the horizontal deflection circuit on the 51WS520?
Why is +135V some times referred to as b+?
I traced the +135V back to a short in the 2SC5778 transistor. It had a short and read 1-2 ohms across it. It is the horizontal deflection trigger transistor. I removed the transistor and connected up the D board. The +15, -15, +135v, +17, -17 volts all read correctly now. The shorted 2SC5778 caused a B+ overcurrent and the manual states that both the B+ overcurrent and the vertical delfection error are simultaneous and reports what it sees first. In this case it was the B+ short causing the error and not the vert. deflection error which it was reporting.
With the 2SC5778 shorted none of the voltages would read correctly.
Should have the new 2SC5778 in next week.
I installed the new 2SC5778. The TV powers up fine and works properly now. Overall, it was a cheap fix.
Hi tvjunk,
I have the same problem with 4 blinks times on power-up,Could you please tell me where is 2SC5778 locate in G board?.
thanks
See complete fix here:
http://www.techlore.com/forum/thread/24561/Please-Help...Sony-WS520-conv...