21 Jan
2017
21 Jan
'17
11:31 p.m.
On Sat, Jan 21, 2017 at 11:33 PM, Adrian Graham
<witchy at binarydinosaurs.co.uk> wrote:
On 21/01/2017 21:59, "Tony Duell"
<ard.p850ug1 at gmail.com> wrote:
What do you mean by 'second output'? How many pins are used on this
'transformer'? If only 2 it is just a simple inductor, again possibly part of
a swtiching regulator.
On Sat, Jan 21, 2017 at 8:43 PM, Adrian Graham
<witchy at binarydinosaurs.co.uk> wrote:
Its second output goes via an IN4148 to the -24V regulator: Hi folks,
Does anyone know what this is? It's obviously a transformer coil(s) but
image search and googling those markings produces nothing:
http://www.binarydinosaurs.co.uk/la4543.jpg
I think the LA number is the number for the ferrite 'pot core' not the
complete transformer.
It looks to be part of a switching regulator circuit. Possibly to generate
other voltages from the 5V line. Can you post a picture of more of the PCB
around it. 
http://www.binarydinosaurs.co.uk/STCExecutelPowerRegulation.jpg
The top black wire is from the PSU and goes left-right (in pairs) GND, +5,
+12, -12. I'd do an underside pic too but the board's covered in analyser
wires at the mo.
The -24V regulator can be seen just above the 4 blue caps, The regulator
that can be seen under the black wire is a 7812. The LF351N has -12V present
at its bias outputs, the opamp to its right has no markings helpfully.
What about that IRF523? That is a power MOSFET transistor and might well
be the chopper in the switching regulator circuit.
Why do you assume the other 8 pin IC is an op-amp?
-tony
