Thank you  both for the reply
Sure, I must check all voltages first and also check if ESR of cappacitors =
is OK.
But now the difficulties come and questions like these arise:

How can I check that there is  CORRECT buss activity ?

How to check that BIOS chip is properly working?( M27W401 chip is  used as =
BIOS). I do not=20
think it is possible with oscilloscope only.

And is there any way how  to check that SDRAM ( there are 4pcs of SDRAM chi=
ps that=20
makes 256 MB RAM)is also good?

And how to check that CPU is running, in other words that RESET sequence wa=
s carried out =20
successfully?
Any idea?

=20
Fo my experience if

CPU  or
BIOS or
SDRAM or
PCB
is faulty or malfunctioning
=20
the device does NOT start

Thank you for your help


> Hi
> A basic approach would be to eyeball the board thoroughly for any obvious
> shorts, burns breaks, leaks smells, then check current draw at correct
> working voltage. If all seems happy, no hot spots/smoke, check for clock =
or
> buss activity with a scope. After that it gets tricky.
>=20
> On Fri, Feb 15, 2013 at 12:54 AM, cdb <colin@btech-online.co.uk> wrote:
>=20
> > On Thu, 14 Feb 2013 20:26:31 +0100, jana1972@centrum.cz wrote:
> > :: How( what pins )  to measure to know it is No.1 or No. 2. or No. 3?
> > :: Any suggestion?
> >
> > Check power supply capacitors, including the ones near any SM chip that
> > might be on the board, for bulging and if possible check their ESR. You=
r
> > meter might read correct voltages +/-, but the circuit might not be get=
ting
> > enough current to actually do anything.
> >
> > Next check the CPU HALT pin, see if it is asserted, check any other IC'=
s
> > for the state of their reset pins.
> >
> > If there is any external device attached, try disconnecting it and see =
if
> > there is any flicker of life.
> >
> > Colin
> > --
> > cdb, colin@btech-online.co.uk on 15/02/2013
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> >
> >
> >
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