Unknown IC on a computer power supply

[LZ1TWB]

Hi all, I have some old ATX PSs here that I would like to modify and use for other purposes but the problem is they don't come with the well known 494 chip but rather with something called "2003". I have found a similar schematic of the PS, but without the IC datasheet I could not do anything.

I have two identical chips here, named 2003 with big font, and on the other row there is "IFFNS00247E" and "BAQ11420423E" for the other one.

Can someone give me some hint where to search, as googling 2003 as obvious gives nothing for an IC. How in the world you could name an IC as a year's number? I have read some other people also asking the forums about this but with no result. I guess this should be not so big secret as PC PS are made with it.

Thanks, Todor

[bharbour]

It may or may not be useful, but there is/was a very common darlington driver chip that was numbered: ULN2003. I think it was 4 or so darlington transistors in a DIP pack. It might be used as a a gate driver or something similar.

BobH

[LZ1TWB]

I know, half the search results brought me to this driver. What I am searching is rather different - it is 16pin DIP which should be push-pull pwm controller with some feedback op-amps and overvoltage protection. It is not so complex, but when you don't know what's inside you cannot do much guessing.

I never thought searching for a pdf datasheet could be so hard.

Todor

[vger]

Todor,

Many OEM's have "House Numbers" put on their chips by the chip maker. For instance, lets say ZYX Power supply company orders 100,000 chips from Ztek. They tell Ztek they need the standard ZT59365 chip, but they want them with the number 2003 printed on them. This often frustrates technicians that try to work on things that are not really intended to be worked on. Believe me I know, having been a technician now for over 35 years.

What is it you want to do with the supplies? Alter the output voltage? Make them adjustable?

I often stop by a computer recycler and see hundreds and hundreds of power supplies going directly to scrap. Nothing wrong with them at all, just not worth the time trying to re-sell or re-use. I can understand wanting re-purpose something you already have, I like to do the same thing. I often have to hold myself in check and say "will it be worth my time and effort?". If I have a 19V power supply and need 15V, do I try to modify the supply or just throw an LM317 after it.

Good luck on your project.

Steve

[LZ1TWB]

I understand, so I put away this board and modified one with the 494. Changed a lot of components, its working good, I will load it heavily these days. I am making a electronic load for that purpose.

Years ago I managed to get ~280W from a 230W PS, with rather small transformer. I think I should get at least 350-400 with this one, which will be some 25-29Amps at 13.8V.

Some OT - no offence, but I get many replies on the forum as why I tend to to this when its on sale already. The answer is pretty simple - when you live in a country where the average salary is $200-$300 you tend to figure out a way to make things yourself, and not buy them. After all that's why this forum is here I think.

Greetings, Todor