Sony SDM-S81R Service Manual

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello Budm,

Sorry for the delay in getting back to the forum. Heres the results of your question from the last post.

1-2=0.L
2-3=3.158M ohms
1-3=0.L

The part number is 11N60C2. Should I replace it along with the IC and the cobbled together zener diode?

Thanks Again,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

The MOSFET is not shorted. Try new fuse at this point and see if you will get 165VDC on that large cap.

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello Budm,

What about the IC, does that need to be replaced? I wasn't able to get a fuse yesterday. Hopefully this week I will get a new one.

Thanks Again,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

Lets try the new fuse first and see what happen. You can change the IC and the MOSFET at the same time.

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello Budm,

Well I replaced the cobbled together diode with the correct value you or one of the other members told me should be there. All new Panasonic FC,FM.FR were used to replace all but the big cap. And now I get 170VDC at the big cap. So am I correct in thinking that the IC needs to be replaced now to get it up and running? If so, let me know and i'll order one ASAP.

Thanks Again,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

OK, it did not blow the fuse but still no output voltage on the secondary side, allcaps are replaced (not the big one). I would say you are safe to go ahead and try replacing the IC, you may as well order the MOSEFT to make it worth the shipping charge.

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello Budm,

I ordered the IC off Ebay. But I haven't found an exact replacement for my mosfet. Digi-Key has a close one but not sure if it will work?

http://www.digikey.com/product-detai...593178?cur=USD

Do you think this part will work? Let me know today if possible.

Thanks,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

The one from Digikey matches/better spec than the original, so you are OK. Just make sure that when you install the new one, make sure that the insulator sheet between the transistor tab is in place, you need to use an Ohm meter to verify that the Tab of the transistor does not have electrical contact with the heat sink. You may want to get more than one. also

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello Budm,

Thanks for the info and all of your assistance thus far. When the parts come and I install them hopefully the monitor leaps back to life, I'll let you and the rest of the forum know.

Much Thanks,
lcdman

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello Again Budm,All,

Well I installed the new "ice" IC and the new mosfet that I received and all I get is the back-light now when plugged in and a very faint buzz noise when first plugged in? I can't turn the back-light on/off with the monitor's power switch only by unplugging from AC. The fuse is still good and I still get 160-165VDC at the large cap. So does that mean that the fault isn't now the power board or the separate inverter board but maybe the logic/video board? My camera's batteries are charging so I can't take a picture of the logic/video board until tomorrow. I can upload one then if needed. Any other things you fellas can think of to check,please feel free to let
me know.

Thanks,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

The backlights on-off control signal is from the main board. The power supply is always on the minute it is plugged into the wall, so the processor on the main board is always running , it sends the signal to turn on/off the backlighs inverter circuits and the T-CON board when power switch is activate. So it looks like you are having problem with the main board also.

[jetadm123]

Re: Sony SDM-S81R Service Manual

Photo of the main board would be helpful.

[kc8adu]

Re: Sony SDM-S81R Service Manual

replace ALL the caps on that psu.
and do a real good job resoldering the rectifiers.the joints crack and kill the ice chip.
the caps dont bulge but the esr is very high on them.

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello All,

I have already replaced all but the big cap on the psu. And re-soldered the rectifiers and replaced the main mosfet and the "ice" IC. So the caps on the main board should be replaced as well? I believe that the main board is now the issue. I'm including pics of the main board now that my camera's battery is charged up.

Thanks,
lcdman

[jetadm123]

Re: Sony SDM-S81R Service Manual

I suggest measuring the voltage at each pin of the voltage regultors U811 and U812 on the main board. Also, what's the part number for each regulator?

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello All,

U811= BA033
U812= D36XX

I'm including a picture with my voltages and where they were measured from. i didn't do the diode check only voltage. If you want a diode check I can do that next. Hopefully there readable after I reduced the picture size to upload to the forum.

If not U811 on its left side 05.08VDC, right side 3.336VDC
If not U812 on its left side 2.435VDC, right side 2.396VDC

Thanks,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

That U812 does not look right, what is the middle pin (tab) voltage?

[lcdman]

Re: Sony SDM-S81R Service Manual

That U812 does not look right, what is the middle pin (tab) voltage?

Hello Budm,

What do you mean by middle tab voltage? Do you mean from the tab on the back to the middle pin? Wouldn't that not work? The same as touching meter leads together in a continuity check. Could you please explain.

Thanks Again,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

The Voltage regulator has 3 pin and one big tab on top, usually the middle pin is tied internally to the Tab. Voltage regulator will have input pin, output pin, Adjustment pin (or ground pin if it is fixed voltage regulator).

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello Budm,

I went back and re-measured the voltage regulator U812. When I measure with the the negative meter lead on the middle leg and the positive meter lead on the outside right leg I get 2.163VDC. And when I measure with the positive meter lead on the middle leg and the negative meter lead on the outside left leg I get
2.438VDC. When the meter leads are reversed I got - readings. Does this new info help to figure this issue out?

Thanks As Always,
lcdman