Sanyo DP37647 no backlight

[Shane711]

Re: Sanyo DP37647 no backlight

From VCC Pin 7 to GND Pin 1 I get a steady voltage of 14.11 volts DC. Now the backlight flashes rapidly all the time, whatever I did caused a change somewhere. Pin 6 I am getting just over 2 volts and pin 2 I getting just over 3 volts. The rest of the pins nothing.

[Shane711]

Re: Sanyo DP37647 no backlight

So Budm, do you think that IC is bad or is it something else? $50 for a used PS but I rather fix the one I have. This is a tough one.

[budm]

Re: Sanyo DP37647 no backlight

Accorrding to the spec sheet of the PFC IC:
VCC (Power Supply)
The VCC pin is the positive supply of the IC and should
be connected to an external auxiliary supply. The
operating range is between 10V and 21V. The turn-on
threshold is at 11.2V and under voltage occurs at
10.2V. There is no internal clamp for a limitation of the
power supply.

So you do have enough DCV to run that PFC IC Controller ICE1PCS02, but you are not geeting te Boosted Voltage.
I have to locate the Diodes in the PFC section to see if they are bad, in the mean time you should inspect the board real close to see if you have any cold solder joints or not.

[budm]

Re: Sanyo DP37647 no backlight

Please check those two diodes I marked to see if they are OK.

[Shane711]

Re: Sanyo DP37647 no backlight

Sorry, got busy because I had to catch up on other stuff. So both of these diodes test out good. I am going to replace the Y Capacitor located where I circled on the board just to see if it make a difference, just because there was a arc there I suspect it may be bad.

[Shane711]

Re: Sanyo DP37647 no backlight

Well, changing that Y Capacitor did not make a difference. I guess my next step is all the polyester caps and see what happens.

[budm]

Re: Sanyo DP37647 no backlight

X (for L and N, and Primary to Secondary), or Y (for L and G, N and G) are not needed for the circuit to function. X and Y caps are for AC line noise filter , do not waste time dealing with X/Y caps. PFC circuit is the one you need to concentrate on.
Those two Diodes I marked, what resistance do you get when you test it using Ohm mode on the meter.