Sanyo dp42848. No picture no sound?has anyone found the problem

[tom66]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

Note that they might not be 8A! But for a 42", that is about right.

F500mA/32V or F630mA/125V etc are all valid

[tomstr]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

Please don't type in all caps -- it's quite hard to read.

Anyway, I know some Delta power supplies of this generation used fuses on the output. I have seen a few of them. Both in Philips LCD TVs.

It would be very rare for a power supply to fail to produce 24V, but still be able to produce the 12V, etc.

Fuses will be marked like "F8A/32V" near them; can you see any?

Does the pink circuit look like a fuse?

[tomstr]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

Note that they might not be 8A! But for a 42", that is about right.

F500mA/32V or F630mA/125V etc are all valid

I don't understand your answer?is it the pink resistor with the fu84k stamped on it?

[tom66]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

I was just providing examples of what the fuses would likely have near them on or on them.
That component is likely not a fuse. It is a safety resistor.

[selldoor]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

The fuses may be under the heatsinks - not logical but possible

Can you post an in focus well lit (No Flash) picture of this half of the board.
Perhaps we can trace back from the 24v pin

[tomstr]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

Ok hold on

[tomstr]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

The fuses may be under the heatsinks - not logical but possible

Can you post an in focus well lit (No Flash) picture of this half of the board.
Perhaps we can trace back from the 24v pin

Try this

[tomstr]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

Or this

[budm]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

On my post 35 and his answer on post 36, I had him check the resistance from the Cathode of the 24v Rectifier Diode to the 24V connector, he had indicated basicaly 0 ohm reading, I was looking for open connection too, that is why I ask him to check, but did not see any from his measurement I asked him to verify. there are 3 reistors (R241A~C) in parallel that looks like thery are used as the fuse, they are OK from his reading.

[tomstr]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

Here are some heatshrink fuses?

[tom66]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

Those resistors could be the minimum load. I have seen them before on Delta PSUs. They seem fond of them.

[selldoor]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

The black tube is a fuse - mains fuse so should be ok but you can check.
I dont think the yellow component is a fuse.
The black box could be a fuse but I doubt it take the glue off and see what it says.
The board description I think is covering the possibility of the board being used at 250v or 120v

The fawn /grey/brown components are fusible resistors you can test them for continuity

[drpj23]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

Isn't there a transistor on smps that monitors the voltage if too high will release excess voltage to a dummy load and if too low will shut the rail off (or not let voltage pass through)? Don't know just talking :P

A precision shunt regulator I think

[budm]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

Those 3 resistor are in series and feed the out put connector, as you can see from the borttom side of the board, the Cathodes feed first inductor L241, output of L421 feeds inductor L240, output of L240 feed the 3 parallel resistors (R241A~B), the output of the resitors feed the 24V output connector. The bleeder resistors are R240A~F which are across the filter caps.

[selldoor]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

The picture I was asking for is the whole half of the board so I can see from the
24v pin which I think is on the row at the bottom up to the part that budm had you checking at the top.

[tomstr]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

Fawn gray and brown?

[tomstr]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

The picture I was asking for is the whole half of the board so I can see from the
24v pin which I think is on the row at the bottom up to the part that budm had you checking at the top.

Ok here

[budm]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

Here is the picture of how the output current flows through the board. There must be something missing from the measurement. I cannot tell without having the board in front of me at this point. There has to be voltage at the 24v pin. The 24v uses fullwave rectifier setup with center tap transformer, so at least one winding must be putting out at least.

[tomstr]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

Those 3 resistor are in series and feed the out put connector, as you can see from the borttom side of the board, the Cathodes feed first inductor L241, output of L421 feeds inductor L240, output of L240 feed the 3 parallel resistors (R241A~B), the output of the resitors feed the 24V output connector. The bleeder resistors are R240A~F which are across the filter caps.

So were does that leave us?

[budm]

Re: Sanyo dp42848. No picture no sound?has anyone found the problem

Do you have two small 12v lamps?