Switching Power Supply Regulator

[Jabber]

Hi i am looking for a datasheet for a Switching Power Supply Regulator.
It is a 8 pin IC on the top is a National Semicoductors symbol.
The number of it is:
M57AL
AMS42577

Hope you can help me.

Thanks

Dennis

[ante]

Hi Dennis,

It’s not easy to find this regulator with what you give us to go on. Is it working or broken, can you from its position find out which pins are connected to what and so on? Maybe it’s possible to find a schematic for the “apparatus” where it is located? Pictures ?

I like to help you if I can! ;D

[Jabber]

Hi Ante,

Sorry for the missing info, i was a little fustrated when i wrote this topic.

The regulator is for a Amstrad  SRX2001 Satelite receiver, I can't find a schematic for it.

The Powersuply is sending a pulsing 0 to 60 V ot on a 24 V pin, i have tried to replace almost everything else but the regulator.

So I see this as my last chance to succseed.

Thanks for your interrest in my little problem.

[ante]

Hi Dennis.

The only Amstrad schematic I got is for the SRX-360, with some luck they might have similarities! I’ll keep my fingers crossed!

Amstrad_SRX360.pdf

[ante]

This is the IC600 on the schematic if I am correct:

UC-3842.pdf