I was taking apart the tv I'm getting parts from for my plasma speaker, and I found what i think is the MOSFET that drives the fly-back.
I was trying to find the specs for it and after about half n hour of searching i couldn't find the datasheet, just tags of it in other sheets that said nothing about it.

Its labeled D1556, I attached a pic.
Anyone know where I could find the specs for this?

 

Hello,

I think it is a NPN planar transistor.
See datasheet for more info.

Bertus

 

Thanks Bertus, thats it
I think its powerful enough for my needs too

 

High power horizontal output with integral damper diode. Beats the 1555 by a mile.

 

Hi all,

Yes, this is almost certainly a 2SD1556. This is a Japanese (actually, far east in general) numbering system for semiconductors unlike the US JEDEC Standard Part Numbering for Diodes & Transistors (1NXXXX, 2NXXXX).

The Japanese started the 2SAXXXX, 2SBXXXX, 2SCXXXX, & 2SDXXXX numbering system back in the 60's I think and most far-east products use these to this day. Note that it doesn't include ICs. The markings are almost always the part number with the 2SY left out, where the Y is the first letter after the initial characters 2S.

Of course, there are always exceptions. For example, a house-marked transistor. This is where a company like ON-Semi will mark the part with any number you want, other than a standard part number. I don't know if that goes for Far-East transistors and Diodes or not. Anyway, since the far east parts leave out the 2S, the rest is probably fair game. This is often done for two reasons. First, to throw off competitors trying to reverse engineer a design and the other reason is that a firm may have a special part numbering system and they prefer to have all their semi's marked with their own part numbers, at least wherever possible.

Regards,
Kamran Kazem
kkazem

 

So, will this not work unless the collector-emitter voltage is at least 1400V?

 

Hello,

The transistor will work fine on lower voltages for Vce.
The 1400 Volts is a test condition.
The Hfe is tested at a Vce of only 5 Volts.

Bertus

 

1400v is the max voltage C/E it can handle.

 

Hmm, then I'm confused.
Why wouldn't the following circuit work?

 

I am asuming there is a common conection betwean B1 & B2 negative?

 

I am asuming there is a common conection betwean B1 & B2 negative?

Nooooo....

I'm guessing I should do that...

 

Revise your schematic to indicate a true 2SD1556 and it needs some current to drive but not much Vbe.

All around one of the best horizontal output transistors made for that frequency but heat sink it with a thick mica washer & plenty of thermal grease or it'll try to arc back. They are not bulletproof. Find an old TV schematic where one was used.

 

All around one of the best horizontal output transistors made for that frequency but heat sink it with a thick mica washer & plenty of thermal grease or it'll try to arc back. They are not bulletproof. Find an old TV schematic where one was used.

arc back?

 

Since there is a huge amount of different Horz O/P transistors the chance of finding a TV circuit with a 2SD1556 transistor init is going to be remote especialy if it was in a monitor. But most Flyback? Horz O/P circuits are basicly the same. I will post several TV Flyback circuits.

 

An a couple more.