Need help finding replacement part

[welchs101]

I have a transistor (picture ...drawn....see attachment). I cant seem to find a replacement for this transistor. Can someone help me?

Dave

 

[ScottyUK]

The casing is a fairly standard design, so what's special about the transistor? What's its function in the circuit, what voltage / current / frequency? The part number appears to be incomplete - not unusual on a surface mount device - so there just isn't enough to work on at the moment.


----------------------------------

If we learn from our mistakes I'm getting a great education!

 

[welchs101]

These parts are off a viewsonic VG150 inverter board. I dont really know any more about the parts than this.

Hoping someone can help.

 

[welchs101]

Correction......its a VG151 inverter board.

 

[IRstuff]

Why not ask Viewsonic?

TTFN

FAQ731-376

 

[welchs101]

I did contact Viewsonic. They were not much help at all. They wanted to sell me a "new inverter".....all i want to do is fix the one i have for a lot less money.

I tried contacting the manufaturer in china but they have not responded to my 3 emails.

 

[Comcokid]

The package appears to be a SOT-89 or TO-283AA

Some suppliers have documents listing package markings. I suggest you do a search.

 

[welchs101]

Thanks. I have looked at the web sites which refer to surface mount device codes but i can not determine anything definative from them. I guess the monitor is going in the trash unless i can figure it out.

 

[IRstuff]

How do you even know that's the bad part?

TTFN

FAQ731-376

 

[welchs101]

Using a multimeter i ohmed out most of the inverter board. I noticed one of the caps looked "different" so i started testing devices in that region. A cap is bad (easy to replace) and the two devices i mentioned are bad and one of the transformers is bad.

 

[MacGyverS2000]

I just looked at your pic... you do realize the tab and pin are supposed to be connected internally, right?

Dan - Owner

http://www.Hi-TecDesigns.com

 

[welchs101]

yes.....the tab and pin 2 are connected/shorted.

Basically since i dont know what the devices are I compared devices on one side of the board (that are exactly the same) to devices on the other side of the board. In doing so i foudn a few devices that were essentially shorted. These are the devices i am trying to replace.

I just cant believe i cant find a replacement. It really just frustrates me .

Thanks.

David

 

[MacGyverS2000]

I don't think you understand... those pins are supposed to be shorted. There's nothing wrong with them (at least due to the short you found).

Dan - Owner

http://www.Hi-TecDesigns.com

 

[welchs101]

Yes, on the "YB" device they are shorted. But these are not the shorted pins i am referring to.

But thanks for responding.

 

[ENEMYJAY]

I had a similar issue trying to find a part, all I did was contact either 247Components.com or digi-key.com and ask for assistance from one of their engineers. They tend to be pretty resourceful when they think there's a chance of a sale in it for them. Good luck

 

[MacGyverS2000]

Jay,

That would be true if this were more than a one-off replacement and something more costly than a $0.05/pc transistor.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[welchs101]

Just wanted to let you all know that i finally found the YB device. It was from a company KEC in Korea. I found the data sheet and then ordered a similar part from Digikey.

Put the part in and the LCD monitor worked!!!!!!!!!!

 

[zappedagain]

How did you find it? Any tricks for the rest of us?

Z

 

[welchs101]

persistance.........i got lucky and found a link which referenced the company. The part in the link was not the part i was looking for but i searched the company's site and there it was. Trust me i tried just about everything: Forums, calling major electronic distributors, everything........just by luck i found the link. I had almost given up but had 5min one day and started looking again and thats when i found the link. Guess its good to put it down for a while and come back to things.