Sony SDM-S81R Service Manual

[lcdman]

Hello All,

Does anyone here have a "FREE" service manual for a Sony SDM-S81R monitor?
Someone has already been inside this unit. And by the the looks of it,didn't know there ass from a hole in the ground. I'm including a stock photo of the board (identical to mine without being butchered). Any help or direction would be great!

Thanks,
lcdman

[jetadm123]

Re: Sony SDM-S81R Service Manual

That looks like the same LG power supply used in a dell 1800fp.

[budm]

Re: Sony SDM-S81R Service Manual

Sure does, check the VCC pin and Ground pin of that SMPS 8-PIN IC (P/N as printed on the IC?) to see if it has low resistance reading.

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello,

Thanks for the information. I looked up a Dell 1800fp. And yes they look very similar aside from the AC outlet connection. There is a zener-diode ZD902 on my PCB. Whomever hacked into this monitor before jerry-rigged this diode. They cut the leads of the original part and soldered a replacement on the component side of the board. So the Dell board part values don't co-inside. Thats kind of why I need service manual/schematic for this board. Its a LG board. With a p/n : 6870T599D10

Thanks So Far,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

The later version of the DELL has Zener Diode (I think it is 18V Zener) to clamp down the VCC pin when the monitor first plug into the outlet to stop it from blowing out the IC. What is the IC number?

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello budm,

The number on the ic is:

ICE 2AS01

(i symbol) 0335LP

VC320290K05

If you could get the value of the needed zener diode from this info would be awesome.

Have A Great Day,
lcdman

[selldoor]

Re: Sony SDM-S81R Service Manual

IC data sheet

[budm]

Re: Sony SDM-S81R Service Manual

Same IC used in the DELL.
20V 1W Zener between VCC PIN and Ground pin. You should check and se if it has low resistance reading between VCC and Ground pin first.
You should download the spec sheet of this IC as provided by selldoor.

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello Budm,Selldoor,

Thanks to both of you for the help and info thus far. I tested the IC and got 14.25k ohms with my Fluke. Does that mean I have to replace the IC along with the 20v 1w zener diode? Where should I source the IC?

Thanks Again,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

14K Ohms is very high, when these IC shorted out, the resistance is less than 200 Ohms. Do you get any voltage at the VCC pin when you apply the power? You should see the meter jumps up. It can be the start up cap, there should be a small 22~47uF connected to this VCC pin. If you look at the app notes of this IC, you will see how it is used, your board will have very similar connection.

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello Budm,

I don't get any DC voltage between VCC and ground pins of the IC when the monitor is attached to an AC outlet. That might be from the two small uf caps that the person before me replaced? There is a Mallory 47uf@50v and a XICON 33uf@25v. I don't know anything about Mallory but XICON is the kind of crap that Radio Shack sells. And they're not low esr caps! So from that, does that mean the IC needs to be replaced? And where would I source it through? I don't want to wait a month to get it from the orient. DigiKey's site says call no stock. As well as Jameco,Mouser.

Take Care,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

I got mine from EBAY. You need to see if you see any pulse shows up at VCC when first plug in, that will tell us if the MOSFET did turn on for second to produce the start up voltage or not. You also have the MOSFET that get the Gate drive signal from the IC. By the way, do you have about 165~170VDC on that large cap (laying on its side) in the primary side?

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello Budm,

I found .004VDC on that large cap on its side. Not good! So which MOSFET is the one you're referring to? Q902,D906,D903,IC905? I can't read all the part numbers without removing them. What about the Mallory and the XICON caps, could they be part of the problem?

Talk To You Tomorrow,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

I did not ask from the beginning if you have already check the main fuse, right now it sounds like the bridge rectifier is not getting the AC, or the output of the rectifier does not reach the cap.
We need GOOD FOCUSED PICTURES of both sides of the board to be able to trace out the connections.

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello Budm,

To honest with you I forgot to check the fuse as well. And its bad now that I checked it. I'm going to get a new one today, and try that. I'm gonna upload better pictures of my board as well.

Take Care,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

Check to see if the bridge is shorted, the MOSFET on that heat sink by the two blue caps.

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello Budm,

I'm going to try to give some info on the bridge rectifier. Let me know if you can make it out all right.

Thanks,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

OK, there is no dead shorts on the bridge. Now put the meter at the two solder pads on the board where the two outer pins of the bridge are connected to and see what resistance you are getting.

[lcdman]

Re: Sony SDM-S81R Service Manual

Hello Budm,

I read 4.765M ohms on those two solder pads. Can I ask why test just those two empty solder pads? One a side note I only get a reading on one side of that mosfet that you mentioned before. Does that mean that it needs to be replaced as well? Its part number is 11n60c2.

Take Care,
lcdman

[budm]

Re: Sony SDM-S81R Service Manual

Those twp pads are the positive and negative terminals that the large cap is connected to and also the load (the MOSFET Source and Drain pin in series with primary winding of the transformer), if the MOSFET is shorted, the resistance reading will be really low less than 50 Ohms enough to take out the fuse.
If you measure the resistance between the negative leg of the cap, it should be connected to one of the two pad, same for the positive leg of the cap, it should be connected to the other pad.
The MOSFET has 3 legs, if you label it from left to right as 1, 2, and 3. Then you will measure the resistance between
1 & 2
1 & 3
2 & 3
See what you get.